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The Effects of Protein Supplements on Muscle Mass, Strength, and Aerobic and Anaerobic Power in Healthy Adults: A Systematic Review
Abstract
Background:
Protein supplements are frequently consumed by athletes and recreationally active adults to achieve greater gains in muscle mass and strength and improve physical performance.
Objective:
This review provides a systematic and comprehensive analysis of the literature that tested the hypothesis that protein supplements accelerate gains in muscle mass and strength resulting in improvements in aerobic and anaerobic power. Evidence statements were created based on an accepted strength of recommendation taxonomy.
Data sources:
English language articles were searched through PubMed and Google Scholar using protein and supplements together with performance, exercise, strength, and muscle, alone or in combination as keywords. Additional articles were retrieved from reference lists found in these papers.
Study selection:
Studies recruiting healthy adults between 18 and 50 years of age that evaluated the effects of protein supplements alone or in combination with carbohydrate on a performance metric (e.g., one repetition maximum or isometric or isokinetic muscle strength), metrics of body composition, or measures of aerobic or anaerobic power were included in this review. The literature search identified 32 articles which incorporated test metrics that dealt exclusively with changes in muscle mass and strength, 5 articles that implemented combined resistance and aerobic training or followed participants during their normal sport training programs, and 1 article that evaluated changes in muscle oxidative enzymes and maximal aerobic power.
Study appraisal and synthesis methods:
All papers were read in detail, and examined for experimental design confounders such as dietary monitoring, history of physical training (i.e., trained and untrained), and the number of participants studied. Studies were also evaluated based on the intensity, frequency, and duration of training, the type and timing of protein supplementation, and the sensitivity of the test metrics.
Results:
For untrained individuals, consuming supplemental protein likely has no impact on lean mass and muscle strength during the initial weeks of resistance training. However, as the duration, frequency, and volume of resistance training increase, protein supplementation may promote muscle hypertrophy and enhance gains in muscle strength in both untrained and trained individuals. Evidence also suggests that protein supplementation may accelerate gains in both aerobic and anaerobic power.
Limitations:
To demonstrate measureable gains in strength and performance with exercise training and protein supplementation, many of the studies reviewed recruited untrained participants. Since skeletal muscle responses to exercise and protein supplementation differ between trained and untrained individuals, findings are not easily generalized for all consumers who may be considering the use of protein supplements.
Conclusions:
This review suggests that protein supplementation may enhance muscle mass and performance when the training stimulus is adequate (e.g., frequency, volume, duration), and dietary intake is consistent with recommendations for physically active individuals.
... A key challenge is to reconcile the effects of dietary protein intake on health and longevity [18]. A highprotein diet (HPD) has received growing attention as a type of health-promoting diet that enriches muscle mass, lowers appetite and weight gain, and decreases blood pressure and serum lipid levels in humans, especially among the elderly [19,20]. Protein-fortified food items and supplements are widely popular in the markets of developed countries [21]. ...
... Previous studies showed that an HPD lowers appetite and weight gain in the elderly [20]. However, intake and BW were not different between the HPD-fed and ND-fed mice in our study. ...
The regulation of the circadian clock plays an important role in influencing physiological conditions. While it is reported that the timing and quantity of energy intake impact circadian regulation, the underlying mechanisms remain unclear. This study investigated the impact of dietary protein intake on peripheral clocks. Firstly, transcriptomic analysis was conducted to investigate molecular targets of low-protein intake. Secondly, mPer2::Luc knock-in mice, fed with either a low-protein, normal, or high-protein diet for 6 weeks, were analyzed for the oscillation of PER2 expression in peripheral tissues and for the expression profiles of circadian and metabolic genes. Lastly, the candidate pathway identified by the in vivo analysis was validated using AML12 cells. As a result, using transcriptomic analysis, we found that the low-protein diet hardly altered the circadian rhythm in the central clock. In animal experiments, expression levels and period lengths of PER2 were different in peripheral tissues depending on dietary protein intake; moreover, mRNA levels of clock-controlled genes and endoplasmic reticulum (ER) stress genes were affected by dietary protein intake. Induction of ER stress in AML12 cells caused an increased amplitude of Clock and Bmal1 and an advanced peak phase of Per2. This result shows that the intake of different dietary protein ratios causes an alteration of the circadian rhythm, especially in the peripheral clock of mice. Dietary protein intake modifies the oscillation of ER stress genes, which may play key roles in the regulation of the circadian clock.
... Nesse sentido, amplamente utilizado no contexto esportivo, o whey protein parece exercer um pequeno a médio efeito ergogênico na musculação. Entretanto, para tal feito, deve haver um estímulo adequado pelo treinamento, assim como uma ingestão alimentar adequada com as recomendações para indivíduos fisicamente ativos 19,20 . Acrescentando-se à suplementação de whey protein, os suplementos BCAA e creatina apresentaram consumo elevado pela amostra estudada, cuja utilização desses três principais suplementos, com prevalência do whey protein, foi predominante em diversos outros estudos com praticantes de musculação 14,[21][22][23] . ...
... Apesar de não ter sido observada associação significativa entre o consumo de suplementos e o tempo de prática de musculação (Tabela 3), a suplementação de proteína pode não ter grande impacto sobre a massa magra e a força muscular durante as semanas iniciais de treinamento de resistência. No entanto, à medida que a duração, a frequência e o volume do treinamento resistido aumentam, a suplementação proteica pode promover a hipertrofia muscular e aumentar os ganhos de força muscular nesses indivíduos 19 . Quanto à prescrição de suplementos alimentares, embora a maior parte dos indivíduos afirmar consumir suplementos alimentares sob orientação do profissional nutricionista, muitos ainda relataram autoprescrição ou outras indicações. ...
Objetivo: Este estudo objetivou avaliar os conhecimentos em nutrição para o esporte e o consumo de suplementos alimentares entre praticantes de musculação de uma rede de academias. Métodos: Trata-se de um estudo transversal, realizado com 168 praticantes de musculação em três unidades de uma rede de
academias de Fortaleza, Ceará, Brasil. Foram avaliados os conhecimentos em nutrição para o esporte e o consumo de suplementos através de um questionário estruturado, abordando os dados de identificação, informações sobre a prática de musculação e sobre a utilização de suplementos e questões objetivas acerca dos conhecimentos de nutrição para o esporte, sendo esses posteriormente classificados em baixo, moderado e alto, de acordo com pontuação obtida. A análise estatística foi realizada pela construção de frequências simples
e relativas, médias e desvio-padrão, assim como por medidas de correlação, com significância fixada em 5%. Resultados: Observou-se que quase metade dos praticantes referiu o consumo de suplementos alimentares. Dentre os suplementos mais consumidos, destacaram-se os proteicos, estando o consumo independente de gênero, tempo de prática de musculação e conhecimentos em nutrição (p
... [22] Some studies showed that untrained individuals consuming supplement protein have no impact on lean mass and muscle strength during initial weeks. [23] However as the duration, frequency and volume of resistance training increases, protein supplementation may promote muscle hypertrophy and strength in untrained and trained. [23] ...
... [23] However as the duration, frequency and volume of resistance training increases, protein supplementation may promote muscle hypertrophy and strength in untrained and trained. [23] ...
REVIEW ON BENEFITS OF PROTEIN SUPPLEMENTS FOR ATHLETES
Ishara M.D.P* and Wimalasiri Y.S.G.
ABSTRACT
As the competitiveness is increasing in the field of sports, the popularity of the protein Supplements has increased in the market. The role of Protein for Athletes are, helping to meet the threshold of their physical activity, increase muscle mass, reduce excessive fat level and improve performances. Thus the objective of this study was to review on benefits of protein supplements for athletes. The data were collected from review articles through Google scholar using dietary protein and protein supplements as key words and additional articles were retrieved from reference lists found in these papers. Dietary proteins which are natural and supply other minerals, water and fibers for athletes. In high protein diets, more undigested protein derived ends up in the large intestine and then more bacterial amino acid takes place in the colon. The colonic fermentation of these amino acids may result in end products having systemic negative and positive and metabolic effects. When athletes find it inconvenient to consume dietary protein sources then portable protein sources, particularly protein supplements, offer an alternative. Artificial sweeteners and sugar substances in these protein supplements may induce adverse effects during long term consumption and if protein supplements used without any appropriate guidance, would affect health. Considering the positive and negative effects of both dietary protein and protein supplements, acquiring protein requirements via dietary proteins would be more beneficial and using the protein supplements as an occasional resource under the supervision as an alternative when they are in an inconvenient moment to get dietary proteins, will be effective.
Keywords: Athletes, Dietary protein, Protein supplements.
... Daily protein consumption can be taken from various sources, such as animals, plants, and milk (Hartman et al., 2007;Hoffman et al., 2004). Protein is the most needed nutrient for people who exercise regularly or athletes (Kårlund et al., 2019;Pasiakos et al., 2015). Beyond normal dietary protein intake, the benefits of additional protein consumption for people of all ages participating in resistance training are to help the body be repaired after exercise, maintain muscle mass, and increase power and strength (Helms et al., 2014;Pasiakos et al., 2015). ...
... Protein is the most needed nutrient for people who exercise regularly or athletes (Kårlund et al., 2019;Pasiakos et al., 2015). Beyond normal dietary protein intake, the benefits of additional protein consumption for people of all ages participating in resistance training are to help the body be repaired after exercise, maintain muscle mass, and increase power and strength (Helms et al., 2014;Pasiakos et al., 2015). Because of the high demands for protein in athletes, assorted supplements such as snacks, drinks, powder, and tablets are valuable useful alternatives for those who cannot obtain adequate protein from daily diet (Kårlund et al., 2019). ...
This study aimed to examine the effect of high protein from chicken breast products during resistance exercise training on muscle mass and strength in healthy Thai male volunteers. In this study was double-blind randomized placebo-controlled study. This study assessed changes in muscle mass and strength of 60 healthy men aged 20-35 years with normal BMI (23.04±2.52 kg/m2). Participants were randomly divided into three groups receiving controlled placebo tablet (CG, n=18, lactose-based containing 12.0 g lactose/day), chicken tablet (CT27, n=18, 27.0 g protein/day), and chicken chip (CC36, n=19, 36.8 g protein/day) during 69-day period. In addition, all groups were instructed to perform the same resistance training program (4 times per week). Body composition (BIA), anthropometry (AMC, CMC), and muscle strength were measured. After 9 weeks of the study, CC36 group had a statistically significant increase (p<0.05) in the percentage of skeletal muscle from baseline when compared other two groups. Additionally, a significant increase (p<0.01) in arm muscle circumference, back-leg extension, and hand grip strength were observed in both groups receiving chicken protein products. The same result was also detected in the placebo group but at a much slower rate. Resistance training exercise along with intake of the chicken protein products could increase muscle mass and strength.
... Many studies have demonstrated that protein intake cannot improve muscle strength in athletes. Protein sources are not likely to have an impact on muscle strength (51,52), and some researchers found statistical significance between protein intake and lean mass and concluded that lean mass gain may not necessarily translate to strength improvements (51,53,54). Schoenfeld et al. concluded that protein timing had a small to moderate effect on muscle hypertrophy, with no significant effect on muscle strength (55). ...
Background
The impact of a protein-rich diet and protein supplements on athletic performance remains a topic of debate. Does protein intake offer benefits for athletes? If so, which specific aspects of athletic performance are most influenced by protein?
Methods
This study aimed to explore the relationship between protein intake and athletic performance. A systematic database search was conducted to identify randomized controlled trials (RCTs) examining the effects of protein intake on athletes’ performance. The databases searched included PubMed, Scopus, Web of Science, EBSCO, and Ovid. The meta-analysis included a total of 28 studies involving 373 athletes. The meta-analysis employed both the fixed-effects model and the random-effects model to investigate the impact of protein intake on sports performance. Subgroup analyses were conducted to provide solid evidence to explain the results of the meta-analysis. Sensitive analysis and funnel plots were used to assess the risk of bias and data robustness.
Results
Overall, protein intake did not show a statistically significant improvement in athletic performance (standardized mean difference [SMD] = 0.12, 95% confidence interval [CI]: −0.01 to 0.25). However, in subgroup analysis, the protein group demonstrated a statistically significant improvement in endurance performance, as indicated by the forest plot of final values (SMD = 0.17, 95% CI: 0.02 to 0.32). Additionally, the change value in the forest plot for endurance performance showed even greater statistical significance than the final value (SMD = 0.31, 95% CI: 0.15 to 0.46). In the subgroup analysis based on physiological indices, muscle glycogen showed a statistically significant improvement in the protein group (standardized mean difference [SMD] = 0.74, 95% confidence interval [CI]: 0.02 to 0.32). Furthermore, subgroup analyses based on protein supplementation strategies revealed that co-ingestion of protein and carbohydrates (CHO) demonstrated statistically significant improvements in endurance performance (SMD = 0.36, 95% CI: 0.11 to 0.61), whereas high protein intake alone did not.
Conclusion
Protein intake appears to provide modest benefits to athletes in improving their performance, particularly by enhancing endurance. Subgroup analysis suggests that protein intake improves muscle glycogen levels and that the co-ingestion of protein with CHO is more effective for endurance athletes than high protein intake alone.
Systematic review registration
https://www.crd.york.ac.uk/prospero/, Identifier CRD42024508021.
... The muscle health of long-distance runners could also be compromised due to the lower protein content, as proteins are important for muscular repair and skeletal muscle mass maintenance [13]. On this subject, low protein intake along with reduced skeletal muscle mass and muscular strength or endurance may hinder performance [14][15][16]. This higher protein content in non-sports persons, on the other hand, may suggest a similar trend of being influenced by high-protein diets associated with weight management [17]. ...
Background: Protein plays an essential role in muscle tissue’s repair, maintenance, and growth. Athletes, especially those involved in long-distance running, experience increased protein turnover because of the physical strain on their muscles, which requires a higher protein intake for effective recovery and adaptation. On the other hand, non-athletes have lower protein requirements due to their lesser physical activity and muscle demands. Analyzing the protein content between these two groups illustrates how physical activity affects protein metabolism, muscle health, and overall nutritional needs, providing valuable insights for customized dietary recommendations that can benefit both athletes and non-athletes.
Objective: To investigate the protein content among university-level long-distance runners and non-sports persons.
Study Design: This study utilized a cross-sectional design.
Material and Methods: Sixty (60) university-level students with long-distance runners (n = 30) and non-sports persons (n = 30) from Punjabi University Patiala were selected using a random sampling technique. To achieve the purpose of the study, the Body composition analyzer GS6.5B Body Building Weight Test System (Version 1.0) was used to measure the protein content of the subjects.
Results: The study found a significant difference in variable protein content between long-distance runners and non-sports persons. The t-value regarding protein content was 3.40 and the p-value was 0.001 and was found to be statistically significant at 0.05 level of significance p<0.05.
Conclusion: This study compared the protein content between university-level long-distance runners and non-sports persons. The protein content of long-distance runners was lower than that of non-sports persons
... When interpreting these findings, it is important to consider that exercising over an extended period is likely to yield better results. Also, additional interventions, such as an increase in daily protein intake during a strength training regimen, may further enhance gains in muscle mass [26]. Conversely, a systematic review and meta-analysis by Fazzini et al. showed that critical illness resulted in an average loss of 1.75% of rectus femoris MT per day during the initial week of illness [27]. ...
Background
The rectus femoris muscle plays an important role in maintaining lower limb stability and biomechanical control during basic physical activities. Both reduced quadriceps strength and decreased muscle thickness of the rectus femoris, as measured by ultrasound, are associated with an increased risk of falls in older adults. We estimated the relative and absolute intra-rater, inter-rater, and inter-day reliability of the procedure.
Methods
A female biologist and a male physical educator, both holding a master’s degree in human movement and rehabilitation, captured ultrasound images of the right rectus femoris muscle in 106 healthy participants (58 females and 48 males), aged 18 to 73 years. Each rater captured three images per participant during each visit, with two visits 7 to 10 days apart. A third person subsequently measured the muscle thickness. We calculated the Intraclass Correlation Coefficients (ICC) using a two-way random model and determined the 95% minimal detectable difference (MDD).
Results
The mean muscle thickness was 2.12 cm. The reliability based on single measurements was as follows: the intra-rater ICC for raters A and B was 0.998 at both visits (MDDs: 0.074–0.082 cm). The inter-rater ICC was 0.976 at visit 1 and 0.977 at visit 2 (MDDs: 0.269–0.270 cm). The inter-day ICC was 0.973 for rater A and 0.972 for rater B (MDDs: 0.286–0.291 cm). Sensitivity analyses accounting for age, sex, and the use of mean measurements produced similar results. The results were homoscedastic.
Conclusions
The rectus femoris muscle thickness was measured with good reliability using ultrasonography across all the settings.
... Studies show beneficial effects such as reduced muscle soreness and markers of muscle damage become more evident when supplemental protein is consumed after daily training sessions. A review stated that protein supplements are used during resistance training to enhance gains in muscle mass and strength and during an aerobic-or sport-based training program to enhance gains in aerobic and anaerobic power [1][2][3][4]. ...
Protein is an essential macronutrient for body function and to improve athletic performance by enhancing the right muscle mass in the athlete. Protein and amino acid supplements are popularly known for sports personalities and active individuals as muscle-boosting, performance-intensifying products, and high-protein, low-carbohydrate diets are traditionally applied for weight-loss purposes.
... Devries stated that Whey protein is one of the highest-quality proteins given its amino acid content (high essential, branched-chain, and leucine amino acid content) and rapid digestibility (Devries, 2015). Furthermore, protein is not just beneficial for the developmental portion, it also helps to promote muscle hypertrophy (Pasiakos et al., 2015). The stimulation of protein synthesis is at a higher rate for whey proteins in comparison to proteins such as soy and casein (Devries, 2015). ...
This book informs readers and athletes of fundamental nutritional guidelines to enhance sport performance, and to reduce the likelihood of malnutrition and vulnerability to nutritional myths and concerns. It contains collected works from Sport and Exercise Studies scholars. The authors thoroughly researched numerous nutrition-related topics and their impact on sport performance and wrote chapters for this book aimed at providing suggestions and improvement strategies for athletes, coaches, health-educators, and other health and movement professionals – as well as any reader interested in improving their dietary choices and physical fitness. Topics discussed in this text include but are not limited to: plant-based diets, hydration and cutting water bloat, eating disorders, intermittent fasting, fat loss diets, ketogenic diets, juice cleanse, supplementation, the impact of social media, and more.
Other than individuals simply wanting to better their diet and sport performance, those who will benefit from reading and applying this work include but are not limited to: (a) physical educators, (b) health educators, (c) coaches, (d) exercise instructors, (e) personal trainers, (f) physical and/or occupational therapists, and (g) nutritionists. This is a practical guide and overview of recommendations and suggestions written by practitioners for practitioners.
... Proteins are important macronutrients with a range of well-recognized health benefits. To start with, protein-rich diets stimulate the production of muscle mass and boost strength (1). Therefore, proteins are excessively consumed by athletes and individuals who are actively training. ...
Proteins are important macronutrients with several beneficial health effects. Today, protein-rich diets are gaining popularity, especially in the context of achieving or preserving a healthy weight. However, epidemiological studies associate long-term consumption of protein-rich diets with adverse health outcomes and increased mortality. These adverse effects, at least partially, are mediated by the activity of microbial products obtained by protein fermentation. Undigested food components reach the colon, where the gut microbiota transforms food residues into various metabolites. Given that side chain groups of amino acids are chemically heterogeneous, undigested proteins provide a mix of substrates for microbial fermentation. By using different amino acids, the gut microbiota can produce toxic, genotoxic, and carcinogenic compounds, but also metabolites that impair normal insulin signaling and cardiovascular function. Biological activity of microbial metabolites can contribute to the development of cardiovascular diseases and cancer, which are associated with high-protein diets. In principle, microbiota metabolic products are beneficial for humans and complementary to human metabolism. However, when diet composition is out of balance (e.g. when proteins are present in an excessive amount), microbiota activity shifts towards production of hazardous metabolites. Therefore, the gut microbiota and its activity must be taken into consideration when designing nutritional strategies to promote health.
... Branched-chain amino acids, particularly leucine, are the primary amino acids that activate protein synthesis in skeletal muscle by the rapamycin (mTOR) pathway. The mTOR pathway regulates muscle protein synthesis in response to elevated levels of essential amino acids [33,34]. ...
Nutrition is a variable risk factor that may be associated with aging. As individuals age, they may experience various nutritional deficiencies and health issues related to inadequate and excessive nutrition. These can include problems with the musculoskeletal system, diminished immune function, metabolic disorders, and cognitive decline. The World Health Organisation has developed a model of healthy aging that focuses on optimizing many aspects of individuals’ intrinsic ability, such as cognition, psychological well-being, sensory function, vitality, and movement. Milk and dairy foods have the potential to help prevent physical and cognitive decline. Milk and dairy foods play a crucial role in providing a variety of essential nutrients, especially during specific stages of life. Dairy products have a significant opportunity to play a vital role in reducing geriatric malnutrition and the loss of muscle mass, bone strength, and functionality. This review aims to comprehensively analyze the potential health benefits of milk and dairy foods. By examining the evidence of associations between these products and the reduction in the incidence of chronic diseases, this study highlights the potential for older adults to lead longer and healthier lives.
... Apart from timing and quality, daily total protein intake is important for performance and body composition gains. Protein supplements are frequently consumed by athletes and recreationally active adults to achieve greater gains in muscle mass and strength and to improve physical performance [19]. Despite the recognition that athletes need additional protein, some athletes are wellfed enough to meet it from their diets. ...
Ergogenic supplements are defined as substances that contribute to or support the doing or production of a job. These supplements are used for many purposes such as increasing the performance of athletes, accelerating recovery in athletes, improving capacity, and reducing and preventing muscle injuries and muscle fatigue. Ergogenic supplements, which are of great interest to athletes and trainers, are classified as nutritional aids, pharmacological aids, psychological aids, mechanical and biomechanical aids, and physiological aids. Among these supplements, they are the most actively used nutritional aids and attract attention in the market as muscle-building nutritional supplements, weight-reducing nutritional supplements, performance-enhancing nutritional supplements, and general health-promoting nutritional supplements. Protein and amino acids provide benefits in long-term or short-term explosive power activities. Fats are used as the main fuel in long-term aerobic exercises. In addition, caffeine, ginseng, antioxidants, and coenzyme Q10 also serve as ergogenic nutritional supplements. It has been reported in studies that minerals such as B, C and E vitamins, chromium, magnesium, iron, and zinc affect sports performance in a good way. In case of deficiency of the aforementioned vitamins and minerals in athletes, many negativities occur. In this study, the use of ergogenic nutritional supplements by athletes before, during, and after training was compiled using the current literature on the types of these supplements.
... A previous research study suggests the opposite, indicating that an extended training duration necessitates increased caloric intake to meet athletes' energy demands [51]. Moreover, a diet rich in protein sources such as fish, meat, eggs, legumes, and dairy is recommended for sports requiring long-duration training sessions [52], particularly in strength sports like powerlifting or weightlifting [53]. The literature is unequivocal regarding carbohydrate consumption: it is essential to meet the energy demands of athletic practice [54]. ...
This study investigated the intricate relationship between strength training and its effects on body image, psychological health, and nutritional habits. By examining 605 participants, divided into two groups based on training frequency, the research aimed to discern how varying intensities of training influenced different wellness facets. The investigation employed a comprehensive survey, gathering demographic data, training specifics, dietary patterns, and psychological characteristics, utilizing statistical tools for analysis. Results unveiled significant differences in dietary habits and psychological profiles between groups with higher and lower training frequencies. The group with more frequent training displayed less favourable health outcomes and suboptimal dietary habits, challenging the prevailing notion that increased training frequency leads to better health. The study emphasized the necessity of a balanced approach to physical training, highlighting the need for personalized strategies that encompass both physical and mental health considerations. The findings exposed the complexities of training regimens and their broader implications on individual health, suggesting that enhanced training frequency alone does not assure improved health outcomes. This research significantly contributed to the domain by providing insights into how the frequency of strength training could differentially affect health and well-being, offering valuable guidelines for fitness professionals and healthcare providers.
... Whey protein is the most prevalent dairy-derived protein, and research has demonstrated that it is the most commonly utilized protein supplement among athletes and fitness enthusiasts [13]. Furthermore, whey protein also confers certain immunoregulatory advantages [14]. ...
Purpose
The impact of dietary nutrients on body growth performance and the composition of gut microbes and metabolites is well-established. In this study, we aimed to determine whether dietary protein can regulate the physiological indexes and changes the intestinal tissue morphology in rats, and if dietary protein was a crucial regulatory factor for the composition, function, and metabolic pathways of the gut microbiota.
Method
A total of thirty male Sprague Dawley (SD) rats (inbred strain, weighted 110 ± 10 g) were randomly assigned to receive diets containing animal-based protein (whey protein, WP), plant-based protein (soybean protein, SP), or a blended protein (soybean-whey proteins, S-WP) for a duration of 8 weeks. To investigate the effects of various protein supplement sources on gut microbiota and metabolites, we performed a high throughput 16S rDNA sequencing association study and fecal metabolomics profiling on the SD rats. Additionally, we performed analyses of growth indexes, serum biochemical indexes, and intestinal morphology.
Results
The rats in S-WP and WP group exhibited a significantly higher body weight and digestibility of dietary protein compared to the SP group (P < 0.05). The serum total protein content of rats in the WP and S-WP groups was significantly higher (P < 0.05) than that in SP group, and the SP group exhibited significantly lower (P < 0.05) serum blood glucose levels compared to the other two groups. The morphological data showed the rats in the S-WP group exhibited significantly longer villus height and shallower crypt depth (P < 0.05) than the SP group. The gut microbial diversity of the SP and S-WP groups exhibited a higher level than that of the WP group, and the microbiomes of the WP and S-WP groups are more similar compared to those of the SP group. The Arachidonic acid metabolism pathway is the most significant KEGG pathway when comparing the WP group and the SP group, as well as when comparing the SP group and the S-WP group.
Conclusion
The type of dietary proteins exerted a significant impact on the physiological indices of SD rats. Intake of S-WP diet can enhance energy provision, improve the body’s digestion and absorption of nutrients, as well as promote intestinal tissue morphology. In addition, dietary protein plays a crucial role in modulating fecal metabolites by regulating the composition of the gut microbiota. Metabolomics analysis revealed that the changes in the levels of arachidonic acid metabolites and secondary bile acid metabolite induced by Clostridium_sensu_stricto_1 and [Eubacterium]_coprostanoligenes_group maybe the primarily causes of intestinal morphological differences.
... Regular assessments and adjustments to dietary strategies are crucial to meet the evolving needs of young athletes. [6][7][8][9][10][11][12][13]: ...
Introduction: The increasing participation of young individuals in sports necessitates a comprehensive understanding of the intricate relationship between nutrition and athletic performance during the critical adolescent years. This introduction sets the stage for an exploration of the dynamic nutritional needs of young athletes, emphasizing the pivotal role of nutrition in supporting growth, energy metabolism, and overall athletic achievement. Current State of Knowledge: The current state of knowledge encompasses an in-depth analysis of key nutritional considerations for young athletes. Examining energy and macronutrient requirements, micronutrient considerations, hydration strategies, and optimal timing of nutrition, this section synthesizes existing research to provide evidence-based guidelines. Furthermore, it addresses the unique challenges posed by different sports and the importance of tailored nutritional approaches for diverse athletic endeavors. The evolving landscape of sports nutrition is also explored, with a specific focus on the benefits and potential risks associated with protein and creatine supplementation. Summary: In summary, this article serves as a comprehensive resource for athletes, coaches, and parents seeking to navigate the intricate intersection of nutrition and young athletes. By elucidating evidence-based strategies and addressing the potential drawbacks and risks associated with certain supplements, the article aims to empower stakeholders with the knowledge needed to make informed decisions regarding the nutritional well-being of young athletes. It underscores the importance of individualized approaches, recognizing the diversity of young athletes and advocating for adaptable nutritional strategies that contribute to both immediate performance gains and sustained health and athletic success.
... A range of strategies has been implemented to mitigate the impact of muscle damage, including both passive and active recovery methods [17], interventions comprising cold water immersion techniques [18], protein consumption [19][20][21], and the use of herbal-based supplementation [22,23]. However, the adoption of herbal-based supplementation as a form of nutritional intervention has gained significant attention in recent years as a means to reduce or prevent muscle damage among athletes and the general population [23][24][25][26]. ...
... These nutritional recommendations often include greater energy and macronutrient intake, along with the implementation of nutrient timing strategies specific to protein and carbohydrates, with an emphasis on the periworkout window. Even supplementation with whey protein alone has been shown to confer favorable improvements on various measures of performance in trained individuals [35]. In the current study, the daily provision of supplemental protein and carbohydrates led to favorable improvements in key performance tasks, which may have been mediated by improvements in fuel availability throughout each day, along with adequate amino acids to support protein synthesis and overall recovery throughout their weekly training activities. ...
Background:
The purpose of this study was to assess the effects of protein and carbohydrate supplementation, with and without creatine, on occupational performance in firefighters.
Methods:
Using a randomized, double-blind approach, thirty male firefighters (age: 34.4 ± 8.4 yrs., height: 1.82 ± 0.07 m; weight: 88.6 ± 12.5 kg; BF%: 17.2 ± 5.8%) were randomized to receive either (A.) 25 g of whey protein isolate + 25 g of carbohydrate powder (ProCarb group); or (B.) ProCarb + 5 g of creatine (Creatine group) in a double-blind fashion over a period of 21-26 days (depending on shift rotations) to evaluate the impact of supplementation on occupation-specific performance. At baseline and following supplementation, firefighters completed a battery of tests. These tests included an aerobic speed test on an air-braked cycle ergometer followed by the hose carry, body drag, stair climb, and Keiser sled hammer for time.
Results:
No significant differences in measures of performance were observed at baseline (p > 0.05). There was a significant main effect for time observed for rescue, stair climb, total time to completion, and time trial performance (p < 0.05). There was a significant group × time (p < 0.05) interaction for rescue and forcible entry. Independent sample t-tests indicated that the Creatine group experienced a greater reduction (from baseline) in completion time for the rescue (1.78 ± 0.57 s, 95% CI: 0.61, 2.95 s, p = 0.004) and forcible entry (2.66 ± 0.97 s, 95% CI: 0.68, 4.65 s, p = 0.01) tests compared to the ProCarb group. No significant group × time interactions were observed for the hose line advance, stair climb, total time to completion, and time trial performance (p > 0.05).
Conclusions:
The addition of supplemental creatine to a protein and carbohydrate supplement to the diet of career firefighters throughout a three week period improves occupational performance in firefighters in specific areas of high-intensity, repetitive actions.
... Seafood offers a high-quality protein content characterized by a complete profile of essential amino acids, which are crucial for muscle protein synthesis but cannot be synthesized by the body [21]. Seafood proteins are rich in essential amino acids, such as leucine, which significantly affect muscle protein synthesis and anabolic signaling pathways [22]. Thus, owing to the high-quality protein content, complete amino acid profile, high bioavailability, and favorable fatty acid composition, there is an increasing demand and interest toward seafood as a highly nutritious protein source. ...
Muscle atrophy is a complex physiological condition caused by a variety of reasons, including muscle disuse, aging, malnutrition, chronic diseases, immobilization, and hormonal imbalance. Beyond its effect on physical appearance, this condition significantly reduces the quality of human life, thus warranting the development of preventive strategies. Although exercising is effective in managing this condition, it is applicable only for individuals who can engage in physical activities and are not bedridden. A combination of exercise and nutritional supplementation has emerged as a more advantageous approach. Here, we evaluated the effects of enzyme-assisted hydrolysates of Mytilus edulis prepared using Protamex (PMH), Alcalase (AMH), or Flavourzyme (FMH) in protecting against muscle atrophy in a dexamethasone (Dex)-induced muscular atrophy model in vitro and in vitro. Alcalase-assisted M. edulis hydrolysate (AMH) was the most efficient among the tested treatments and resulted in higher protein recovery (57.06 ± 0.42%) and abundant amino acid composition (43,158 mg/100 g; 43.16%). AMH treatment also escalated the proliferation of C2C12 cells while increasing the total number of nuclei, myotube coverage, and myotube diameter. These results were corroborated by a successful reduction in the levels of proteins responsible for muscle atrophy, including E3 ubiquitin ligases, and an increase in the expression of proteins associated with muscle hypertrophy, including myogenin and MyHC. These results were further solidified by the successful enhancement of locomotor ability and body weight in zebrafish following AMH treatment. Thus, these findings highlight the potential of AMH in recovery from muscle atrophy.
... Given the lack of change in strength and FFM in all groups, it is likely the training stimulus was inadequate, limiting the impact of protein supplementation. Protein supplementation has been consistently shown to be an effective strategy for increasing total daily protein intake and enhancing training adaptations in physically active populations, including elite sportspeople, military personnel and recreationally active individuals (9,11,40,41). Ingesting 20-40 g of protein has been proposed to maximise the muscle protein synthesis (MPS) response to exercise (42) and, when consumed prior to sleep, supports MPS throughout the night (43). Protein supplementation at this time of day may be practically advantageous for military recruits due to negligible protein intakes in the evening period (13). ...
Dietary protein is crucial for optimising physical training adaptations such as muscular strength and mass, which are key aims for athletic populations, including British Army recruits. New recruits fail to meet the recommended protein intake during basic training (BT), with negligible amounts consumed in the evening. This study assessed the influence of a daily bolus of protein prior to sleep on performance adaptations, body composition and recovery in British Army recruits. 99 men and 23 women [mean ± standard deviation (SD): age: 21.3 ± 3.5 years, height: 174.8 ± 8.4 cm, body mass 75.4 ± 12.2 kg] were randomised into a dietary control (CON), carbohydrate placebo (PLA), moderate (20 g) protein (MOD) or high (60 g) protein (HIGH) supplementation group. Supplements were isocaloric and were consumed on weekday evenings between 2000 and 2100 for 12 weeks during BT. Performance tests (mid-thigh pull, medicine ball throw, 2 km run time, maximal push-up, and maximal vertical jump) and body composition were assessed at the start and end of BT. Dietary intake, energy expenditure, salivary hormones, urinary nitrogen balance, perceived muscle soreness, rating of perceived exertion, mood, and fatigue were assessed at the start, middle and end of BT. Protein supplementation increased protein intake in HIGH (2.16 ± 0.50 g⸱kg⁻¹⸱day⁻¹) and MOD (1.71 ± 0.48 g⸱kg⁻¹⸱day⁻¹) compared to CON (1.17 ± 0.24 g⸱kg⁻¹⸱day⁻¹) and PLA (1.31 ± 0.29 g⸱kg⁻¹⸱day⁻¹; p < 0.001). Despite this, there was no impact of supplementation on mid-thigh pull performance (CON = 7 ± 19%, PLA = 7 ± 19%, MOD = 0 ± 16%, and HIGH = 4 ± 14%; p = 0.554) or any other performance measures (p > 0.05). Fat-free mass changes were also similar between groups (CON = 4 ± 3%, PLA = 4 ± 4%, MOD = 3 ± 3%, HIGH = 5 ± 4%, p = 0.959). There was no impact of protein supplementation on any other body composition or recovery measure. We conclude no benefits of pre-bed protein supplementation to improve performance, body composition and recovery during BT. It is possible the training stimulus was great enough, limiting the impact of protein supplementation. However, the high degree of inter-participant variability suggests an individualised use of protein supplementation should be explored, particularly in those who consume sub-optimal (<1.6 g⸱kg⁻¹⸱day⁻¹) habitual amounts of protein.
Clinical trial registration: The study was registered with ClinicalTrials.gov, U.S. national institutes (identifier: NCT05998590).
... The factors associated with protein timing and the quality of protein used are equally relevant to assessing the effects of dietary protein intake during long-lasting exercise participation [9]. Therefore, a large number of meta-analyses and experimental and observational studies without intervention have been conducted to summarize the effects of the consumption of protein supplements on the occurrence of changes in body composition, muscular power and strength or the levels of bodily adaptation to exercise [10][11][12][13][14][15][16][17][18][19][20]. ...
Athletes need to develop a relatively high muscle mass and low body adipose tissue for the sake of better athletic performance. A full range of nine essential amino acids and eleven non-essential amino acids have to attend in appropriate amounts for protein biosynthesis. The aim of the observational comparative cross-sectional study was to assess the association between the diet quality profile and training-induced muscle mass estimated by bioelectrical impedance among elite male athletes. The research sample comprised 18.1 ± 3.1 year-old Lithuanian professional male athletes (n = 234). The study participants were enrolled to complete 24-h dietary recalls of three non-consecutive days. The body composition was assessed using the bioelectrical impedance analysis (BIA) method. The present study showed a significant insufficiency of the mean carbohydrate intake of 5.7 g/kg/day in a group of aerobic male athletes. The lower muscle mass of aerobic male athletes was related to the lower-carbohydrate diet (adjusted odd ratio (ORadj) 0.3; 95% confidence interval (CI): 0.1–0.7). The mean protein intake of 1.8 g/kg/day was optimal for anabolism in the samples of both anaerobic and aerobic male athletes. The protein intake in appropriate doses was potentially associated with an increase in muscle mass only in anaerobic male athletes (ORadj 2.2; 95% CI: 1.3–3.7). The positive relationship was revealed between the possible muscle mass gain and the increased intakes of amino acids such as isoleucine and histidine among anaerobic athletes (ORadj 2.9; 95% CI: 1.1–4.7 and ORadj 2.9; 95% CI: 1.0–4.3, respectively). An inverse feasible association was indicated between a higher intake of valine and lower muscle mass quantities among anaerobic male athletes (ORadj 0.1; 95% CI: 0.1–0.5). The recommendations for sports nutritionists should emphasize the necessity of advising professional athletes on dietary strategies on how to manipulate dietary amino acid composition with respect to achieving long-term body composition goals.
... g/kg of dietary protein every 3-4 h following exercise to support recovery from and adaption to regular exercise training [8]. Among healthy adults, increasing dietary protein intake promotes numerous physiological benefits when paired with regular exercise, including improved recovery times, reduced muscular soreness, improvements in muscular strength and hypertrophy, and, when paired with a hypocaloric diet, greater reductions in fat mass and greater retention of lean mass [9][10][11][12][13][14]. Among people living with T1D, protein has also been shown to cause a dose-dependent elevation in blood glucose levels, peaking around 3 h after consumption and remaining elevated for at least 5 h and possibly as long as 12 h [15][16][17][18][19][20]. ...
Little is known about the role of post-exercise protein intake on post-exercise glycemia. Secondary analyses were conducted to evaluate the role of post-exercise protein intake on post-exercise glycemia using data from an exercise pilot study. Adults with T1D (n = 11), with an average age of 33.0 ± 11.4 years and BMI of 25.1 ± 3.4, participated in isoenergetic sessions of high-intensity interval training (HIIT) or moderate-intensity continuous training (MICT). Participants completed food records on the days of exercise and provided continuous glucose monitoring data throughout the study, from which time in range (TIR, 70–180 mg/dL), time above range (TAR, >180 mg/dL), and time below range (TBR, <70 mg/dL) were calculated from exercise cessation until the following morning. Mixed effects regression models, adjusted for carbohydrate intake, diabetes duration, and lean mass, assessed the relationship between post-exercise protein intake on TIR, TAR, and TBR following exercise. No association was observed between protein intake and TIR, TAR, or TBR (p-values ≥ 0.07); however, a borderline significant reduction of −1.9% (95% CI: −3.9%, 0.0%; p = 0.05) TBR per 20 g protein was observed following MICT in analyses stratified by exercise mode. Increasing post-exercise protein intake may be a promising strategy to mitigate the risk of hypoglycemia following MICT.
... In this regard, several lines of evidence support that whey protein, which contains a high content of L-leucine and essential amino acids, stimulates the highest increases in postexercise muscle protein synthesis. A seminal meta-analysis by Morton et al. [14] indicates that recreationally trained individuals obtain strength and muscle mass benefits from protein supplementation whereas novice trainees do not, and this is further supported by a prior meta-analysis by Pasiakos et al. [15]. These results may be associated with large and variable gains in fitness in novice trainees which may mask any small benefits of protein supplementation. ...
Purpose of review:
The purpose of this opinion paper is to provide current-day and evidence-based information regarding dietary supplements that support resistance training adaptations or acutely enhance strength-power or endurance performance.
Recent findings:
Several independent lines of evidence support that higher protein diets, which can be readily achieved through animal-based protein supplements, optimize muscle mass during periods of resistance training, and this likely facilitates strength increases. Creatine monohydrate supplementation and peri-exercise caffeine consumption also enhance strength and power through distinct mechanisms. Supplements that favorably affect aspects of endurance performance include peri-exercise caffeine, nitrate-containing supplements (e.g., beet root juice), and sodium bicarbonate consumption. Further, beta-alanine supplementation can enhance high-intensity endurance exercise efforts.
Summary:
Select dietary supplements can enhance strength and endurance outcomes, and take-home recommendations will be provided for athletes and practitioners aiming to adopt these strategies.
... A cafeína é um dos ingredientes mais comuns encontrados nos suplementos prétreino e tem sido amplamente estudada por seu potencial de aumentar a energia e melhorar o desempenho físico. A cafeína atua como um estimulante do sistema nervoso central, reduzindo a percepção de esforço e fadiga, além de aumentar a alerta mental e o estado de vigilância durante o treino (Pasiakos et al., 2015). ...
Este artigo abordou a utilização de suplementos por praticantes de musculação, destacando seu papel como complemento para melhorar o desempenho, a recuperação e os resultados estéticos. Os suplementos podem fornecer nutrientes específicos que beneficiam o desenvolvimento muscular, a redução da fadiga e a melhoria do desempenho atlético. No entanto, é importante ressaltar que eles não substituem uma alimentação equilibrada e um programa de treinamento adequado. A segurança, a eficácia e a qualidade dos suplementos devem ser consideradas, buscando orientação profissional e informações confiáveis. Cada indivíduo é único, e é essencial adaptar a utilização de suplementos às necessidades individuais. Uma abordagem equilibrada, priorizando uma alimentação saudável e o treinamento consistente, é fundamental para alcançar os resultados desejados. Os suplementos devem ser vistos como uma ferramenta adicional, utilizados de forma consciente e responsável, em conjunto com uma abordagem global de saúde e bem-estar.
... The results showed a significant increase in the FSR rate in rats treated with WP hydrolyzate compared to the amino acid mix and control groups. At the same and athletes, as it plays an important role in the metabolism of energy-providing carbohydrates during exercise and protein synthesis [34,35]. In a study by Wang et al. on post-exercise WP + carbohydrate supplementation in rats, they found that the mTOR signaling pathway was activated and increased insulin level and MPS in rats administered the active substance compared to the placebo group [36]. ...
This study aimed to examine the impact of varying doses of whey protein (WP) and amylopectin/chromium complex (ACr) supplementation on muscle protein synthesis (MPS), amino acid and insulin levels, and the rapamycin (mTOR) signaling pathways in exercised rats. A total of 72 rats were randomly divided into nine groups: (1) Exercise (Ex), (2) Ex + WPI to (5) Ex + WPIV with various oral doses of whey protein (0.465, 1.55, 2.33, and 3.1 g/kg) and (6) Ex + WPI + ACr to (9) Ex + WPIV + ACr with various doses of whey protein combined with 0.155 g/kg ACr. On the day of single-dose administration, the products were given by oral gavage after exercise. To measure the protein fractional synthesis rate (FSR), a bolus dose of deuterium-labeled phenylalanine was given, and its effects were evaluated 1 h after supplementation. Rats that received 3.1 g/kg of whey protein (WP) combined with ACr exhibited the most significant increase in muscle protein synthesis (MPS) compared to the Ex group (115.7%, p < 0.0001). In comparison to rats that received the same dose of WP alone, those given the combination of WP and ACr at the same dosage showed a 14.3% increase in MPS (p < 0.0001). Furthermore, the WP (3.1 g/kg) + ACr group exhibited the highest elevation in serum insulin levels when compared to the Ex group (111.9%, p < 0.0001). Among the different groups, the WP (2.33 g/kg) + ACr group demonstrated the greatest increase in mTOR levels (224.2%, p < 0.0001). Additionally, the combination of WP (2.33 g/kg) and ACr resulted in a 169.8% increase in 4E-BP1 levels (p < 0.0001), while S6K1 levels rose by 141.2% in the WP (2.33 g/kg) + ACr group (p < 0.0001). Overall, supplementation with various doses of WP combined with ACr increased MPS and enhanced the mTOR signaling pathway compared to WP alone and the Ex group.
... Verschiedene Publikationen haben gezeigt, dass ≥ 65-jährige Personen infolge einer höher liegenden Metabolisierungsschwelle deutlich mehr Protein pro Mahlzeit benötigen als jüngere Erwachsene, um die Muskelproteineigensynthese maximal zu stimulieren [8,9,10,11,12,13]. Seit mehreren Jahren wird daher empfohlen, den täg lichen Proteinbedarf auf die drei Hauptmahlzeiten gleichmässig zu verteilen und dabei zu gewährleisten, dass die jeweilige Proteinmenge von 25 g pro Hauptmahlzeit nicht unterschritten wird [14]. ...
The Impact of Nutrition on Muscle Health in Older Individuals Abstract: The age-related change in the importance of nutrition for muscle health starts at the age of 50. Considering its effects on the mobility and physical independence of older people, the aging of the musculoskeletal system represents one of the greatest public health challenges and tasks for a demographically aging Switzerland. In particular sarcopenia, a pathological decrease in muscle strength, muscle mass and muscle function beyond the physiological age-related changes, correlates with a significantly increased risk of falls as well as increasing morbidity and mortality. Common chronic diseases related to old age not only promote additional muscle loss but also frailty, leading to an additional decline of the quality of life. General practitioners play a crucial role in the initial assessment of changing life circumstances and activity profiles of older people. Thanks to their medical care over many years they are able to identify functional impairments of their aging patients at an early stage and address them in time. This is important because the combination of a high-protein diet and exercise may be extremely effective for improving muscle health and function. Eating more proteins (taking into account the newly revised and increased daily protein requirement for healthy seniors of 1,0-1,2g/kg body weight (bw)) can significantly slow down age-related muscle loss. Depending on age and comorbidities, the daily protein requirement might be even higher (1,5 to 2,0g/kg bw). According to current studies, a minimal protein amount of 25-35g per main dish is recommended for optimal muscle growth stimulation among older individiuals. Thanks to their highly potent boosting power on myofibrillar protein synthesis rates the amino acid L-leucine and L-leucine-rich foods play an important role in elderly people's diet.
... g/kg or an absolute dose of 20-40 g of protein following exercise, as well as the consumption of high protein meals every 3-4 h following exercise to support recovery from and adaptation to an exercise bout [20,21]. Furthermore, in active individuals, a higher protein diet (25-30% energy from protein) combined with regular exercise has been associated with improved muscular strength and reduced soreness, and a significant decrease in fat mass when paired with a caloric deficit [22][23][24]. It is possible that similar protein recommendations may also improve glycemia following exercise for those with T1D, although minimal data exist in this area. ...
Citation: Muntis, F.R.; Smith-Ryan, A.E.; Crandell, J.; Evenson, K.R.; Maahs, D.M.; Seid, M.; Shaikh, S.R.; Mayer-Davis, E.J. A High Protein Diet Is Associated with Improved Glycemic Control Following Exercise among Adolescents with Type 1 Diabetes. Nutrients 2023, 15, 1981. Abstract: Nutritional strategies are needed to aid people with type 1 diabetes (T1D) in managing glycemia following exercise. Secondary analyses were conducted from a randomized trial of an adap-tive behavioral intervention to assess the relationship between post-exercise and daily protein (g/kg) intake on glycemia following moderate-to-vigorous physical activity (MVPA) among adolescents with T1D. Adolescents (n = 112) with T1D, 14.5 (13.8, 15.7) years of age, and 36.6% overweight or obese, provided measures of glycemia using continuous glucose monitoring (percent time above range [TAR, >180 mg/dL], time-in-range [TIR, 70-180 mg/dL], time-below-range [TBR, <70 mg/dL]), self-reported physical activity (previous day physical activity recalls), and 24 h dietary recall data at baseline and 6 months post-intervention. Mixed effects regression models adjusted for design (ran-domization assignment, study site), demographic, clinical, anthropometric, dietary, physical activity, and timing covariates estimated the association between post-exercise and daily protein intake on TAR, TIR, and TBR from the cessation of MVPA bouts until the following morning. Daily protein intakes of ≥1.2 g/kg/day were associated with 6.9% (p = 0.03) greater TIR and −8.0% (p = 0.02) less TAR following exercise, however, no association was observed between post-exercise protein intake and post-exercise glycemia. Following current sports nutrition guidelines for daily protein intake may promote improved glycemia following exercise among adolescents with T1D.
... In addition, participants with previous RT experience and participants without training experience also provide different adaptations (Lopez et al., 2021). A review shows that when training stimuli are optimal (e.g., frequency, volume, duration), additional protein supplementation can improve muscle hypertrophy and performance (Pasiakos et al., 2015). According to the ACSM position stand study, the recommended frequency for training is 2-3 days per week (d.w-1) for beginner level, 3-4 d. w-1 for secondary education, and 4-5 d. w-1 for advanced training. ...
The overarching aim of this study was to investigate the combined effects of chocolate milk consumption (500 mL) with 8-week of resistance training on muscle hypertrophy, body composition, and maximal strength in untrained healthy men. A total of 22 Participants were randomly divided into two experimental groups: combined resistance training (3 sessions per week for 8 weeks) and chocolate milk consumptions (include 30 g protein) Resistance Training Chocolate Milk (RTCM) (Age: 20.9 ± 0.9 years old) and resistance training (RT) only (Age: 19.8 ± 0.7 years old). Muscle thickness (MT), using a portable ultrasound, body composition, body mass, maximal strength (one repetition maximum (1 RM), counter movement jump (CMJ) and peak power (PP) were determined at baseline and 8 weeks later. In the RTCM, finding showed a significant improvement in the outcomes compared to the RT group, besides the main effect of time (pre and post). The 1 RM total increased by 36.7% in RTCM group compared to 17.6% increased in the RT group (p < 0.001). Muscle thickness increased by 20.8% in the RTCM group and 9.1% in the RT group (p < 0.001). In the RTCM group, the PP increased by 37.8% compared to only 13.8% increase in the RT group (p = 0.001). The group*time interaction effect was significant for MT, 1RM, CMJ, and PP (p < 0.05), and it was observed that the RTCM and the 8-week resistance training protocol maximized performance. Body fat percentage (%) decreased more in the RTCM (18.9%) group than in the RT (6.7%) group (p = 0.002). In conclusion, chocolate milk (500 mL) with high protein content consumed in addition to resistance training provided superior gains in terms of MT, 1 RM, body composition, CMJ, and PP. The finding of the study demonstrated the positive effect of casein-based protein (chocolate milk) and resistance training on the muscle performance. Chocolate milk consumption has a more positive effect on muscle strength when combined with RT and should be considered as a suitable post-exercise nutritional supplement. Future research could be conducted with a larger number of participants of different ages and longer study durations.
... Due to higher energy expenditure, athletes consume supplements which allow them to sustain the training load [16]. According to our findings, the most used supplement was whey protein (n = 72; 64.28%), which is used primarily to increase adaptations mediated by resistance exercise, despite the different effects on the body [27]. However, some CFPs may attribute performance improvement to whey protein, despite being used after training sessions to improve muscle recovery [28,29]. ...
PurposeWe aimed to verify the prevalence of dietary supplements among CrossFit practitioners (CFPs), considering gender and training status. Still, we aimed to determine the type, reasons, and associated factors of dietary supplement utilization among CFPs.Methods
This is a cross-sectional, exploratory, and descriptive study with the snowball sampling method. Data were collected through online questionnaires using the Google Forms® tool. We included CFPs aged 18–64 years, from Aug 1, 2020, to Sept 31, 2020. The questionnaire contained questions to assess the prevalence, type, and reasons for supplement use; also, we assessed information about sociodemographic variables and the prevalence of the main chronic morbidities. To analyze aspects of eating behavior and sleep-related parameters, we applied the three-factor eating questionnaire (TFEQ)-R21 and the Pittsburgh Sleep Quality Index questionnaire (PSQI), respectively.ResultsWe assessed one hundred twelve (n = 112; 57 men; 55 women) CFPs (28.9 ± 7.64 years old; body mass index (BMI), 25.5 ± 4.83 kg/m2). Eighty-seven (50 men; 37 women; 28.2 ± 6.66 years old; BMI, 25.4 ± 4.55 kg/m2) reported using dietary supplements. Whey protein was the most used supplement (n = 70), followed by creatine (n = 54). Cognitive restraint (a dimension of eating behavior) score was higher in supplement users than in non-users (51.7 ± 18.6 vs. 42.6 ± 20.5; p = 0.040). Sleep-related parameters did not differ between supplement users and non-users. The most associated factors to supplement use were sex (being man; OR, 7.99; p = 0.007), sleep quality (poor; OR, 5.27; p = 0.045), CrossFit level (as prescribed (RX); OR, 4.51; p = 0.031), and cognitive restraint (OR, 1.03; p = 0.029).Conclusion
The CFPs, especially RX and Elite ones, showed a higher prevalence of supplement utilization. Anabolic-related supplements (i.e., whey protein and creatine) were the most used; moreover, several CFPs used supplements not supported by scientific evidence. Cognitive restraint score was higher in supplement users than in non-users. RX level, being men, and poor sleep quality were associated with supplement utilization. These data draw attention to the necessity of nutritional education for CrossFit coaches and athletes. Broader studies are necessary to confirm our findings.
... Po intensywnych ćwiczeniach ważne jest dostarczenie białka do pobudzenia syntezy białek mięśniowych (MPS), głównie dla sportowców ćwiczących siłowo. Sportowcy wytrzymałościowi spożywają żywność bogatą w białko po treningu w celu zapobiegania katabolizmowi mięśni [9,10]. Biegacze narciarscy znacznie częściej jedzą podczas ćwiczeń w porównaniu z osobami ćwiczącymi siłowo. ...
Streszczenie Przedmiot badań Przestrzeganie zasad prawidłowego żywienia jest ważne dla utrzymania zdrowia i jak najlepszej dyspozycji fizycznej sportowców. Cel badań Celem badań była analiza jakościowa sposobu żywienia i suplementacji wybranej grupy sportowców – biegaczy narciarskich oraz osób, które ćwiczą na siłowni. Materiał i metody Badaniem objęto 117 osób czynnie uprawiających sport. W badaniu wzięło udział 64. biegaczy narciarskich (32 kobiety i 32 mężczyzn) i 53 osoby, które regularnie ćwiczą na siłowni (33 kobiet i 20 mężczyzn). W celu przeprowadzenia oceny jakościowej sposobu żywienia sportowców przeprowadzono wywiad w formie autorskiej ankiety elektronicznej. Badania przeprowadzone zostały w sposób zdalny i były anonimowe. Ankieta zawierała 60 pytań jednokrotnego i wielokrotnego wyboru z możliwością dodania własnej odpowiedzi. Pytania zostały dostosowane do grupy, do której były kierowane i ich wybór był pokierowany znajomością specyfiki sportu. Wyniki Na podstawie przeprowadzonych badań, wykazano szereg nieprawidłowości w sposobie żywienia sportowców: zarówno w grupie biegaczy narciarskich, jak i osób ćwiczących siłowo. Wykazano nieprawidłowości w podaży płynów biegaczy narciarskich. Przyjmują oni zbyt małą ilość płynów w porównaniu do podejmowanego wysiłku fizycznego. Wykazano periodyzację w żywieniu biegaczy narciarskich spowodowaną przygotowaniami do sezonu startowego, co może mieć wpływ na wyniki badania. Wnioski Ze względu na liczne błędy żywieniowe występujące wśród sportowców biorących udział w badaniu, istnieje potrzeba prowadzenia badań w tym kierunku oraz szersza edukacja środowiska sportowego Abstract Introduction Complying with the rules of good nutrition is important to maintain the athletes’ good health and high sporting performance. Aim The aim of the present investigations was to perform a qualitative analysis of nutrition and food supplementation in a selected group of athletes – ski runners and individuals doing physical activity in the gym. Methods The study included 117 persons regularly doing sport: 64 ski runners (32 women and 32 men) as well as 53 persons regularly doing physical activity in the gym. In order to perform a quantitative assessment of the way of nutrition of the examined athletes, a survey was performed in the form of the researchers’ own electronic questionnaire. The studies were performed on-line and were anonymous. The questionnaire contained 60 single-choice and multiple-choice test questions with the possibility of adding the respondents’ own answers. The questions were adjusted to the group at which they were targeted and they were chosen basing on the knowledge of specific character of the sport. Results On the basis of the performed studies a number of nutritional abnormalities were found both in the group of ski runners and the persons doing physical activity in the gym. In the group of ski runners nutritional mistakes included inadequate hydration, that is too low supply of fluids in relation to the undertaken physical effort. Nutrition periodization was detected in ski runners, related to their preparation for the starting season, which may affect the results of the study. Conclusions Because of multiple nutritional mistakes made by the athletes who took part in the study, it is necessary to perform further investigations in this field and also to better educate the sport environment.
... Strong evidence supports the effectiveness of protein supplementation to increase muscle mass, strength, and performance in healthy subjects, particularly when combined with exercise training [1][2][3]. Although extensive research has studied the effects of protein supplementation in resistance-trained individuals [1,4], endurance athletes might also benefit from this nutritional intervention, especially during periods of high energy demands (e.g. ...
Background: The effects of pre-sleep protein supplementation on endurance athletes remain unclear, particularly whether its poten- tial benefits are due to the timing of protein intake or solely to an increased total protein intake. We assessed the effects of pre-sleep protein supplementation in professional cyclists during a training camp accounting for the influence of protein timing.
Methods: Twenty-four professional U23 cyclists (19 ± 1 years, peak oxygen uptake: 79.8 ± 4.9 ml/kg/min) participated in a six-day training camp. Participants were randomized to consume a protein supplement (40 g of casein) before sleep (n = 8) or in the afternoon (n = 8), or an isoenergetic placebo (40 g of carbohy- drates) before sleep (n = 8). Indicators of fatigue/recovery (Hooper index, Recovery–Stress Questionnaire for Athletes, countermove- ment jump), body composition, and performance (1-, 5-, and 20- minute time trials, as well as the estimated critical power) were assessed as study outcomes.
Results: The training camp resulted in a significant (p < 0.001) increase in training loads (e.g. training stress score of 659 ± 122 per week during the preceding month versus 1207 ± 122 during the training camp), which induced an increase in fatigue indicators (e.g. time effect for Hooper index p < 0.001) and a decrease in performance (e.g. time effect for critical power p = 0.002). Protein intake was very high in all the participants (>2.5 g/kg on average), with significantly higher levels found in the two protein supplement groups compared to the placebo group (p < 0.001). No significant between-group differences were found for any of the analyzed outcomes (all p > 0.05). Conclusions: Protein supplementation, whether administered before sleep or earlier in the day, exerts no beneficial effects during a short-term strenuous training period in professional cyclists, who naturally consume a high-protein diet.
... Studies have shown that WP is a protein supplement widely used by athletes and physical activity practitioners. (Pasiakos et al., 2015;Vasconcelos et al., 2021). This high usage rate is mainly due to its significant effects on protein synthesis, lean mass gain and sports performance (Vasconcelos et al., 2021). ...
Expensive and time-consuming methods are currently used to identify manipulated whey protein concentrate (WPC). We tested the application of attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy to detect and quantify adulteration of WPC with wheat flour (WF). ATR-FTIR is based on the interaction between IR radiation and the molecular bonds in the samples, allowing the capture of its vibration energy and the acquisition of spectra with information that can be used to identify and quantify functional groups. WPC Samples were adulterated with different percentages of WF and spectra were collected. Amide I and II bands exhibit a decreasing protein content when more WF is added. Conversely, at the carbohydrate characteristic band (1080 cm⁻¹), there is an increasing intensity as more WF is added. Partial least squares (PLS) regression models presented low prediction errors and high coefficients of determination. Furthermore, one of the models was chosen for a blind prediction test of 10 samples adulterated with random amounts of WF, and it could make reasonable predictions of the actual levels of adulteration. Therefore, ATR-FTIR spectroscopy coupled with multivariate analysis shows strong potential to detect adulteration in WPC with WF and the capability to quantify the added mass content.
... Due to higher energy expenditure, athletes consume supplements which allow them to sustain the training load [16]. According to our findings, the most used supplement was whey protein (n = 72; 64.28%), which is used primarily to increase adaptations mediated by resistance exercise, despite the different effects on the body [27]. However, some CFPs may attribute performance improvement to whey protein, despite being used after training sessions to improve muscle recovery [28,29]. ...
Purpose: We aimed to determine the prevalence of the use of supplements among CFPs. Moreover, we sought to elucidate which factors may be associated with dietary restraint, a dimension of eating behavior that seems to be crucial for food intake, energy availability, fatigue, and performance.
Methods CFPs aged 18-64 years (n = 112; 57 male; 55 female) were included in this cross-sectional, exploratory, and descriptive study. They answered an online questionnaire containing questions to assess prevalence, type, and reasons for supplements use, besides information about sociodemographic variables and prevalence of the main chronic morbidities. To analyze aspects of eating behavior, the “Three-factor eating questionnaire (TFEQ) - R21" was used. The Pittsburgh Sleep Quality Index questionnaire (PSQI) was used to assess sleep time and quality.
Results: Eighty-seven CFPs (50 male; 37 female) reported currently use of dietary supplements. Whey protein was the most used supplement (n = 70), followed by creatine (n = 54). Eating behavior dimensions of emotional eating, binge eating, and cognitive restraint displayed no differences between genders and CFPs of levels.
Conclusion: CFPs seem to be using some supplements with purposes which conflict with those supported by scientific evidence. Regarding eating behavior dimensions, physical exercise may be able to suppress emotional eating, possibly justifying the lack of difference in our results. The use of supplement is prevalent among CF practitioners, but it seems they need nutrition education.
Importance
Major concerns regarding individuals who adhere to a vegan diet are whether they meet protein and essential amino acid recommendations and how reliant they are on ultraprocessed foods.
Objectives
To investigate whether individuals who adhere to a vegan diet meet protein and essential amino acid recommendations and, as secondary objectives, to determine ultraprocessed food intake and potential factors associated with inadequate protein intake in this population.
Design, Setting, and Participants
This cross-sectional survey study was conducted between September 2021 and January 2023 in Brazil among male and female adults (aged 18 years or older) who adhered to a vegan diet recruited from social media platforms.
Exposure
Adherence to a vegan diet and unprocessed and minimally processed foods and ultraprocessed food consumption.
Main Outcomes and Measures
Protein and essential amino acid intake and food consumption by processing level were assessed using a 1-day food diary. Nutrient adequacy ratios were calculated by dividing nutrient intake by its recommendation (using scores truncated at 1) for each participant and then finding the mean across participants for each nutrient. The mean adequacy ratio was the mean of all nutrient adequacy ratios.
Results
Of 1014 participants who completed the survey, 774 individuals (median [IQR] age, 29 [24-35] years; 637 female [82.3%]) were confirmed as adhering to a vegan diet and provided adequate food recalls, among whom 558 individuals reported body weight and so had relative protein and amino acid intake values available. The median (IQR) body mass index (calculated as weight in kilograms divided by height in meters squared) of participants was 22.6 (20.3-24.8). The nutrient adequacy ratio of protein was 0.93 (95% CI, 0.91-0.94); for essential amino acids, ratios ranged from 0.90 (95% CI, 0.89-0.92) for lysine to 0.98 (95% CI, 0.97-0.99) for phenylalanine and tyrosine. The mean adequacy ratio for protein and all amino acids was 0.95 (95% CI, 0.94-0.96). The median intake level was 66.5% (95% CI, 65.0%-67.9%) of total energy intake for unprocessed and minimally processed food and 13.2% (95% CI, 12.4%-14.4%) of total energy intake for ultraprocessed food. Adjusted logistic regression models showed that consuming protein supplements (odds ratio [OR], 0.06 [95% CI 0.02-0.14]; P < .001) or textured soy protein (OR, 0.32 [95% CI, 0.17-0.59]; P < .001) was associated with decreased odds of inadequate protein intake. Higher ultraprocessed food intake levels were also associated with decreased odds of inadequate protein intake (eg, fourth vs first quartile of intake: OR, 0.16 [95% CI, 0.07-0.33]; P < .001), and higher unprocessed and minimally processed protein intake levels were associated with increased odds of inadequate protein intake (eg, fourth vs first quartile of intake: OR, 12.42 [95% CI, 5.56-29.51]; P < .001).
Conclusions and Relevance
In this study, most individuals who adhered to a vegan diet attained protein and essential amino acid intake recommendations, largely based their diet of unprocessed and minimally processed food, and had a significantly lower proportion of ultraprocessed food intake compared with previous reports. Participants consuming less ultraprocessed food were more likely to have inadequate protein intake, suggesting a significant reliance on ultraprocessed proteins for this population.
Background
It is unclear whether resistance training in combination with different timing of protein intake might have differential effects on muscle hypertrophy, strength, and performance. Therefore, we compared the effects of 8 weeks of resistance training combined with two different high-protein diet strategies (immediately pre-and after, or 3 h pre and after exercise) in resistance-trained males.
Methods
Forty resistance-trained males (24 ± 4 years) performed 8 weeks of resistance training combined with 2 g kg⁻¹ d⁻¹ protein. Body composition, muscular performance, and biochemical markers were assessed pre and post-intervention.
Results
Nine participants (four from 3 h group and five from the immediate group) withdrew from the study. Therefore, 31 participants completed the study. All measures of skeletal muscle mass, Australian pull-up, and muscle strength, significantly increased post-intervention in both groups (p < 0.05). The biochemical marker urea also significantly increased from pre to post in both groups (p < 0.05). There were no significant between-group differences (p > 0.05).
Conclusion
High-protein diet enhances muscular performance and skeletal muscle mass in resistance-trained males, irrespective of intake time. Consequently, the total daily protein intake appears to be the primary factor in facilitating muscle growth induced by exercise.
Background
Emerging evidence suggests health-promoting properties of increased protein intake. There is increased interest in plant protein but a dearth of information in relation to its impact on muscle function. The objective of the present work was to examine the impact of intake of different types of proteins on muscle functional parameters including handgrip strength, biomarkers of metabolic health, sleep quality and quality of life in a group of older adults.
Methods
Healthy men and women aged 50 years and older entered a double-blinded, randomised, controlled nutritional intervention study with three parallel arms: high plant protein, high dairy protein and low protein. Participants consumed once daily a ready-to-mix shake (containing 20 g of protein in high protein groups) for 12 weeks. Changes in handgrip and leg strength, body composition, metabolic health, quality of life and sleep quality were analysed by linear mixed models in an intention-to-treat approach.
Results
Eligible participants (n = 171) were randomly assigned to the groups (plant: n = 60, dairy: n = 56, low protein: n = 55) and 141 completed the study. Handgrip strength increased after the intervention (Ptime = 0.038), with no significant difference between the groups. There was no significant difference between groups for any other health outcomes.
Conclusions
In a population of older adults, increasing protein intake by 20 g daily for 12 weeks (whether plant-based or dairy-based) did not result in significant differences in muscle function, body composition, metabolic health, sleep quality or quality of life, compared with the low protein group.
Protein: Structure and Function
Protein supplementation often refers to increasing the intake of this particular macronutrient through dietary supplements in the form of powders, ready-to-drink shakes, and bars. The primary purpose of protein supplementation is to augment dietary protein intake, aiding individuals in meeting their protein requirements, especially when it may be challenging to do so through regular food (i.e. chicken, beef, fish, pork, etc.) sources alone. A large body of evidence shows that protein has an important role in exercising and sedentary individuals. A PubMed search of "protein and exercise performance" reveals thousands of publications. Despite the considerable volume of evidence, it is somewhat surprising that several persistent questions and misconceptions about protein exist. The following are addressed: 1) Is protein harmful to your kidneys? 2) Does consuming "excess" protein increase fat mass? 3) Can dietary protein have a harmful effect on bone health? 4) Can vegans and vegetarians consume enough protein to support training adaptations? 5) Is cheese or peanut butter a good protein source? 6) Does consuming meat (i.e., animal protein) cause unfavorable health outcomes? 7) Do you need protein if you are not physically active? 8) Do you need to consume protein ≤ 1 hour following resistance training sessions to create an anabolic environment in skeletal muscle? 9) Do endurance athletes need additional protein? 10) Does one need protein supplements to meet the daily requirements of exercise-trained individuals? 11) Is there a limit to how much protein one can consume in a single meal? To address these questions, we have conducted a thorough scientific assessment of the literature concerning protein supplementation.
Importance: Major concerns regarding vegan dieters are whether they meet protein and essential amino acids (EAA) recommendations, and how reliant they are on ultra-processed foods (UPF).
Objectives: To investigate whether vegan dieters meet protein and EAA recommendations. As secondary objectives, to determine UPF intake and potential predictors of inadequate protein intake in this population. Design: A survey conducted between September 2021 and January 2023.
Setting: Brazil. Participants: Vegan dieters of both sexes, aged 18 years or older, following a vegan diet for at least 6 months. Exposure: Adherence to a vegan diet, and unprocessed and minimally processed foods (UMPF) and UPF consumption. Main outcome measures: Protein and EAA intake, and food consumption according to processing level (Nova classification). Results: One thousand and fourteen participants completed the survey, and 774 confirmed vegan dieters with adequate food recalls were included in the analysis. Most participants (74%) met daily protein intake according to the Recommended Dietary Allowance (RDA) (median: 1.12 g/kg/day, 95%CI 1.05; 1.16). Median EAA intake was also above RDA (with 71-91% meeting recommendations). Median UMPF intake was 66.5% (95%CI 65.0; 67.9) of total energy intake (TEI), whereas UPF consumption was 13.2% TEI (95%CI 12.4; 14.4). Adjusted logistic regression models showed that consuming protein supplements or textured soy protein, higher caloric, and higher UPF intakes were associated with reduced odds of inadequate protein intake, and that higher UMPF intakes were associated with increased odds of inadequate protein intake. Conclusions and Relevance: The majority of vegan dieters attained protein and EAA intake recommendations, largely based their diet on UMPF, and had a significantly lower proportion of UPF as compared to previous reports on vegans and overall Brazilian population. Importantly, participants consuming less UPF more likely exhibited inadequate protein intake, suggesting the importance of ultra-processed proteins for this population.
Background
Although many studies have investigated the association between body composition, cancer risk and mortality, predicting these risks through a single body composition measurement undoubtedly increases the limitations of the study. Few studies have explored the association between the trajectory of changes in body composition and the risk of cancer and death. We aimed to explore the association of predicted lean mass trajectories with cancer risk, cancer‐specific mortality and all‐cause mortality.
Methods
The participants in this study were all from the Kailuan cohort, a prospective, periodic, resurvey cohort study initiated in 2006. Latent mixture modelling was used to identify predicted lean mass trajectories for 2006–2010. The hazard ratios (HRs) and 95% confidence intervals (95% CIs) of the Cox proportional hazard models were used to describe the association between predicted lean mass trajectories and cancer risk and cancer‐specific and all‐cause mortality during follow‐up (2010–2021).
Results
A total of 44 374 participants (average age, 53.01 ± 11.41 years, 78.99% men and 21.01% women) were enrolled in this study. Five distinct trajectories were identified: low‐stable ( n = 12 060), low‐increasing ( n = 8027), moderately stable‐decreasing ( n = 4725), moderately stable‐increasing (n = 8053) and high‐stable ( n = 11 509). During the 11‐year follow‐up period, 2183 cancer events were recorded. After adjusting for age, predicted fat mass in 2010, sex, BMI, sedentary, physical activity, smoke, alcohol use, salt consumption, high‐fat diet, high‐sensitivity C‐reactive protein, serum creatinine, family history of tumour, hypertension, diabetes mellitus, compared with the low‐stable group, participants in the low‐increasing group (HR = 0.851, 95% CI, 0.748–0.969), moderately stable‐increasing group (HR = 0.803, 95% CI, 0.697–0.925) and high‐stable group (HR = 0.770, 95% CI, 0.659–0.901) had a lower cancer risk, but not in the moderately stable‐decreasing group (HR = 0.864, 95% CI, 0.735–1.015). Compared with the low‐stable group, the risk of cancer‐specific mortality was reduced by 25.4% (8.8–38.9%), 36.5% (20.3–49.4%) and 35.4% (17.9–49.2%), and the risk of all‐cause mortality was reduced by 24.2% (16.9–30.8%), 37.0% (30.0–43.2%) and 47.4% (41.0–53.1%) in the low‐increasing, moderately stable‐increasing group and high‐stable groups, respectively.
Conclusions
Predicted lean mass trajectories may be closely associated with cancer risk and cancer‐specific and all‐cause mortality. Regular monitoring of body composition is necessary.
This study aimed to investigate the effects of natural daily adequate protein intake on the anaerobic power of bodybuilders undergoing an 8-week resistance training program. Thirty-one participants were randomly assigned to a group (n=31) who consumed their daily protein requirements from their regular diet. Participants' age, height, weight, and BMI were measured before and after the program. The anaerobic power of all participants was assessed pre- and post-8-week resistance training program through tests including 1 RM (Bench Press), 1 RM (Squats), 30-meter sprint test, Vertical Jump Test, and Peak Power Test (wingate test). The results showed a significant improvement in the anaerobic power of participants after the 8-week program. These findings suggest that natural daily adequate protein intake from regular diet can lead to significant improvements in anaerobic power of bodybuilders undergoing an 8-week resistance training program. Therefore, coaches and athletes can focus on a balanced, nutrient-dense diet to meet their protein needs and enhance their anaerobic power without relying solely on protein supplements.
Introduction: Findings around nutrient timing require appropriate context because factors such as age, gender, fitness level, previous fueling status, diet status, training volume, training intensity, program design, and time before upcoming training or competition can influence the extent to which timing can play a role in the adaptive response to exercise. Thus, nutrient timing is a feeding strategy that in almost all situations can be useful for promoting recovery and training adaptations. Objective: A systematic review was carried out to elucidate the importance of macronutrient consumption by highly trained athletes on performance and body composition. Methods: The present study followed a systematic review model (PRISMA). The search strategy was carried out in PubMed, Cochrane Library, Web of Science, Scopus, and Google Scholar databases, using scientific articles from 2009 to 2021. The low quality of evidence was attributed to case reports, editorials, and brief communications, according to the GRADE instrument. The risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: After the study eligibility process, a total of 42 scientifically favorable articles were found to compose the systematic review. Biases did not compromise the scientific basis of the studies. The amount depends on the mode and intensity of exercise, the quality of protein ingested, and the individual's energy and carbohydrate status. However, it should be noted that there is preliminary evidence that consuming much higher amounts of protein (>3 g/kg/d) may confer a benefit concerning body composition. Concerns that protein intake within this range is unhealthy are unfounded in healthy, exercising individuals. One should try to consume whole foods that contain high-quality protein sources. Timing of protein intake in the period spanning the exercise session can provide several benefits, including improved recovery and greater gains in lean body mass. Essential amino acids and leucine supplements are beneficial for the exercising individual by increasing muscle protein synthesis rates, decreasing muscle protein breakdown, and possibly aiding exercise recovery.
Objective: The aim of this study was to investigate the influence of different categories of dietary supplements on the body composition of resistance-training practitioners. Methods: Participants of both sexes and ages 20 to 59 y participated in this cross-sectional study. The use of dietary supplements was investigated and classified into three categories: sports foods, medical supplements , and ergogenic supplements. One-way analysis of covariance adjusted for age, type of exercise, frequency of exercise, total amount of daily exercise, and exercise intensity was used in the analysis. Results: Of 427 participants, 278 (65%), were supplement consumers. Women who consumed sports foods had higher percentages of skeletal muscle (P = 0.014) and lower percentages of body fat than women who did not take supplements (P = 0.031). Furthermore, women who used medicinal supplements had greater visceral fat levels than women who did not (P = 0.019). No significant differences were found between type of supplement used and body composition among men (P > 0.05). Conclusions: Consuming sports foods was associated with higher percentages of skeletal muscle and lower percentages of body fat; women who used medical supplements had higher visceral fat levels.
Objective:
The aim of this study was to investigate the influence of different categories of dietary supplements on the body composition of resistance-training practitioners.
Methods:
Participants of both sexes and ages 20 to 59 y participated in this cross-sectional study. The use of dietary supplements was investigated and classified into three categories: sports foods, medical supplements, and ergogenic supplements. One-way analysis of covariance adjusted for age, type of exercise, frequency of exercise, total amount of daily exercise, and exercise intensity was used in the analysis.
Results:
Of 427 participants, 278 (65%), were supplement consumers. Women who consumed sports foods had higher percentages of skeletal muscle (P = 0.014) and lower percentages of body fat than women who did not take supplements (P = 0.031). Furthermore, women who used medicinal supplements had greater visceral fat levels than women who did not (P = 0.019). No significant differences were found between type of supplement used and body composition among men (P > 0.05).
Conclusions:
Consuming sports foods was associated with higher percentages of skeletal muscle and lower percentages of body fat; women who used medical supplements had higher visceral fat levels.
Background & Aims
Skeletal muscle losses (both quantitative and qualitative) and the consequent risk of sarcopenia are important issues in people living with HIV (PLWH), even when treated with antiretroviral therapies (ART). We aimed to conduct a systematic review (SR) investigating the effects of dietary interventions with proteins, amino acids, and other nitrogenated compounds on the skeletal muscle of PLWH.
Methods
We searched the published literature until August 24th, 2020, including clinical trials predominantly with AIDS-free PLWH treated with ART.
Results
From the 82 studies initially selected, 75 were excluded for the following reasons: nutritional interventions different from nitrogenated compounds; non-nutritional interventions; lack of information on body composition; and studies with most participants with AIDS. From the publications included (n = 7), the majority were performed with small and heterogeneous samples. None of the studies included any new-generation ART or pre- or post-exposition drugs. Two studies found benefits of supplementation on muscle mass; one was performed in a very unfavorable socioeconomic setting, and the supplementation was based on food-derived substances. The other study supplemented creatine, and its benefits were found only when combined with physical exercise training and only by one of the methods of body composition analysis (DXA).
Conclusions
Our results showed that nutritional interventions with proteins, amino acids, or other nitrogenated compounds could not improve the skeletal muscle mass in PLWH. Further studies are needed, with bigger sample sizes and more precise control of ART schemes.
Systematic Review Registration
PROSPERO registration number CRD42019139981.
1 Finland HÄKKINEN K., KOMI P.V. & TESCH P.A. Effect of ccmbined concentric ard eccentric strength training and detraining on force-time, muscle fiber-and metabolic characteristics of leg extensor muscles. Scand. J ,Sports Sci. 3 (2): 50-58, 1981. Prog¡essive strength training of combined concentric and eccentric contractions were performed three times a week for 16 weeks by 14 males {20-30 yrs of age) accustomed to weight training. The training peeriod was iollowed bv 8 weeks of detraining. The training program consisted mainly of dynamic exeicises for the ieg-extensovs with loads of 80 to 120 of one maximum repetition The training caused significant improvements in-maximal force (p < 0.001) and various force-time (p (0.05-4.01) para¡àeters. Du¡ing thg I'ast trarning àionìh tbe inãrease in force was gireatly tri¡nited' and there was ¿ decrease in th,e force-time parameters. The marked improvements in mwcle strength were accompanied by ccnsiderable intemål qdaptatioos ,Ín-ttre tnaCned muscle, as Judged from l¡rcreases (p < 0-001) ,iqr. the fibet ãeas ôt tËe Ïast fi¡¡itch (FT) and slow twitch (ST) fibers. Durlng early conditioning improvement i! the qqgs! jump w,as related to tl.e relãtive hypertrop]ty of tr1l ii¡eis fo <0.01). No sier¡j-Êi,cå,r¡t ct¡anges ,in tJre er¡zyme aittv¡tiês oi mÍoki¡¡ase-a¡¡d creatine kirmse were found as a result of-tra¡rrir}g, but i,ndividt¡al charrges in my-o-kinase activity $/ere related to the relative. hypertrop'hy of FT fibers-(p ç 0.05) and Improvernent i+ the squat jump (p < O.Of)-during early conditiontuag. All the ada,p-iatlo:ns'-incilcating musõle hypertrophy occurred. prtm@lv during the last two training mo¡rths. Decreases (p (0.001) in maxirnal force during the detrairring were accompâ-nied bv a sisrificår¡t rediuction in the fi¡b,er areas of ttle fC tp < 0.01) and ST (p < 0.05) tvpes end by a change in bödy-antliropometry.-A periodiè-and partial usage. of àccentr-ic contráctions,-together with conèentric training' is suggested to be effectiùe in training for-maximal force and äso for force-time eharacteristics. In training of longer durations the specific effects of strength trainlng are-obviot¡s and explaiñable by adaptatlons in the trained muscle. Keg tenns: erìzJûne actlvities, muscle mechanics, muscle metabollsn, muscle streng:th.
The effect of 10 wk of protein-supplement timing on strength, power, and body composition was examined in 33 resistance-trained men. Participants were randomly assigned to a protein supplement either provided in the morning and evening ( n = 13) or provided immediately before and immediately after workouts ( n = 13). In addition, 7 participants agreed to serve as a control group and did not use any protein or other nutritional supplement. During each testing session participants were assessed for strength (one-repetition-maximum [1RM] bench press and squat), power (5 repetitions performed at 80% of 1RM in both the bench press and the squat), and body composition. A significant main effect for all 3 groups in strength improvement was seen in 1RM bench press (120.6 ± 20.5 kg vs. 125.4 ± 16.7 at Week 0 and Week 10 testing, respectively) and 1RM squat (154.5 ± 28.4 kg vs. 169.0 ± 25.5 at Week 0 and Week 10 testing, respectively). However, no significant between-groups interactions were seen in 1RM squat or 1RM bench press. Significant main effects were also seen in both upper and lower body peak and mean power, but no significant differences were seen between groups. No changes in body mass or percent body fat were seen in any of the groups. Results indicate that the time of protein-supplement ingestion in resistance-trained athletes during a 10-wk training program does not provide any added benefit to strength, power, or body-composition changes.
Current methods for clinical estimation of total body skeletal muscle mass have significant limitations. We tested the hypothesis that creatine (methyl-d3) dilution (D3-creatine) measured by enrichment of urine D3-creatinine reveals total body creatine pool size, providing an accurate estimate of total body skeletal muscle mass. Healthy subjects with different muscle masses (n=35: 20 men [19-30y, 70-84y], 15 post-menopausal women [51-62y, 70-84y]), were housed for 5 days. Optimal tracer dose was explored with single oral doses of 30, 60, or 100 mg D3-creatine given on Day 1. Serial plasma samples were collected for D3-creatine pharmacokinetics. All urine was collected through Day 5. Creatine and creatinine (deuterated and unlabeled) were measured by liquid chromatography mass spectrometry. Total body creatine pool size and muscle mass were calculated from D3-creatinine enrichment in urine. Muscle mass was also measured by magnetic resonance imaging (MRI), dual-energy x-ray absorptiometry (DXA), and traditional 24-h urine creatinine. D3-creatine was rapidly absorbed and cleared with variable urinary excretion. Isotopic steady-state of D3-creatinine enrichment in the urine was achieved by 30.7 ± 11.2 h. Mean steady-state enrichment in urine provided muscle mass estimates that correlated well with MRI estimates for all subjects (r=0.868, P<0.0001), with less bias compared with lean body mass (LBM) assessment by DXA, which overestimated muscle mass compared with MRI. The dilution of an oral D3-creatine dose determined by urine D3-creatinine enrichment provides an estimate of total body muscle mass strongly correlated with estimates from serial MRI with less bias than total LBM assessment by DXA.
Muscle hypertrophy following resistance training (RT) involves activation of myofibrillar protein synthesis (MPS) to expand the myofibrillar protein pool. The degree of hypertrophy following RT is, however, highly variable and thus we sought to determine the relationship between the acute activation of MPS and RT-induced hypertrophy. We measured MPS and signalling protein activation after the first session of resistance exercise (RE) in untrained men (n = 23) and then examined the relation between MPS with magnetic resonance image determined hypertrophy. To measure MPS, young men (24±1 yr; body mass index = 26.4±0.9 kg•m(2)) underwent a primed constant infusion of L-[ring-(13)C6] phenylalanine to measure MPS at rest, and acutely following their first bout of RE prior to 16 wk of RT. Rates of MPS were increased 235±38% (P<0.001) above rest 60-180 min post-exercise and 184±28% (P = 0.037) 180-360 min post exercise. Quadriceps volume increased 7.9±1.6% (-1.9-24.7%) (P<0.001) after training. There was no correlation between changes in quadriceps muscle volume and acute rates of MPS measured over 1-3 h (r = 0.02), 3-6 h (r = 0.16) or the aggregate 1-6 h post-exercise period (r = 0.10). Hypertrophy after chronic RT was correlated (r = 0.42, P = 0.05) with phosphorylation of 4E-BP1(Thr37/46) at 1 hour post RE. We conclude that acute measures of MPS following an initial exposure to RE in novices are not correlated with muscle hypertrophy following chronic RT.
Protein timing is a popular dietary strategy designed to optimize the adaptive response to exercise. The strategy involves consuming protein in and around a training session in an effort to facilitate muscular repair and remodeling, and thereby enhance post-exercise strength- and hypertrophy-related adaptations. Despite the apparent biological plausibility of the strategy, however, the effectiveness of protein timing in chronic training studies has been decidedly mixed. The purpose of this paper therefore was to conduct a multi-level meta-regression of randomized controlled trials to determine whether protein timing is a viable strategy for enhancing post-exercise muscular adaptations. The strength analysis comprised 478 subjects and 96 ESs, nested within 41 treatment or control groups and 20 studies. The hypertrophy analysis comprised 525 subjects and 132 ESs, nested with 47 treatment or control groups and 23 studies. A simple pooled analysis of protein timing without controlling for covariates showed a small to moderate effect on muscle hypertrophy with no significant effect found on muscle strength. In the full meta-regression model controlling for all covariates, however, no significant differences were found between treatment and control for strength or hypertrophy. The reduced model was not significantly different from the full model for either strength or hypertrophy. With respect to hypertrophy, total protein intake was the strongest predictor of ES magnitude. These results refute the commonly held belief that the timing of protein intake in and around a training session is critical to muscular adaptations and indicate that consuming adequate protein in combination with resistance exercise is the key factor for maximizing muscle protein accretion.
Two of the most popular forms of protein on the market are whey and casein. Both proteins are derived from milk but each protein differs in absorption rate and bioavailability, thus it is possible that each type of protein may contribute differently to the adaptations elicited through resistance training. Therefore, the purpose of this study was to investigate the potential effects of ingestion of two types of protein in conjunction with a controlled resistance training program in collegiate female basketball players. Sixteen NCAA Division III female basketball players were matched according to body mass and randomly assigned in a double-blind manner to consume 24 g whey protein (WP) (N = 8, 20.0 ± 1.9 years, 1.58 ± 0.27 m, 66. 0 ± 4.9 kg, 27.0 ± 4.9 %BF) or 24 g casein protein (CP) (N = 8, 21.0 ± 2.8 years, 1.53 ± 0.29 m, 68.0 ± 2.9 kg, 25.0 ± 5.7 %BF) immediately pre- and post-exercise for eight weeks. Subjects participated in a supervised 4-day per week undulating periodized training program. At 0 and 8 weeks, subjects underwent DXA body composition analysis, and at 0 and 8 weeks underwent one repetition maximum (1RM) strength, muscle endurance, vertical jump, 5-10-5 agility run, and broad jump testing sessions. Data were analyzed using repeated measures ANOVA, and presented as mean ± SD changes from baseline after 60 days. No significant group x time interaction effects were observed among groups in changes in any variable (p > 0.05). A significant time effect was observed for body fat (WP: -2.0 ± 1.1 %BF; CP: -1.0 ± 1.6 %BF, p < 0.001), lean mass (WP: 1.5 ± 1.0 kg; CP: 1. 4 ± 1.0 kg, p < 0.001), fat mass (WP: -1.3 ± 1.2 kg; CP: -0.6 ± 1.4 kg, p < 0.001), leg press 1RM (WP: 88.7 ± 43.9 kg; CP: 90.0 ± 48.5 kg, p < 0.001), bench press 1RM (WP: 7.5 ± 4.6 kg; CP: 4.3 ± 4.5 kg, p = 0.01), vertical jump (WP: 4.1 ± 1.8 cm; CP: 3.5 ± 7.6 cm, p < 0.001), 5-10-5 (WP: -0.3 ± 0.2 sec; CP: -0.09 ± 0.42 sec, p < 0.001), and broad jump (WP: 10.4 ± 6.6 cm; CP: 12. 9 ± 7.1 cm, p < 0.001). The combination of a controlled undulating resistance training program with pre- and post-exercise protein supplementation is capable of inducing significant changes in performance and body composition. There does not appear to be a difference in the performance- enhancing effects between whey and casein proteins. Key pointsFemales can experience and increase in performance makers from consuming protein after resistance training.Females can have a decreased body fat composition when ingesting protein with daily resistance training and conditioning.There was no significant difference in performance markers between whey and casein.
Protein supplements (PSs) are, after multivitamins, the most frequently consumed dietary supplement by U.S. military personnel. Warfighters believe that PSs will improve health, promote muscle strength, and enhance physical performance. The estimated prevalence of regular PS use by military personnel is nearly 20% or more in active-duty personnel, which is comparable to collegiate athletes and recreationally active adults, but higher than that for average U.S. civilians. Although the acute metabolic effects of PS ingestion are well described, little is known regarding the benefits of PS use by warfighters in response to the metabolic demands of military operations. When dietary protein intake approaches 1.5 g ⋅ kg(-1) ⋅ d(-1), and energy intake matches energy expenditure, the use of PSs by most physically active military personnel may not be necessary. However, dismounted infantry often perform operations consisting of long periods of strenuous physical activity coupled with inadequate dietary energy and protein intake. In these situations, the use of PSs may have efficacy for preserving fat-free mass. This article reviews the available literature regarding the prevalence of PS use among military personnel. Furthermore, it highlights the unique metabolic stressors affecting U.S. military personnel and discusses potential conditions during which protein supplementation might be beneficial.
Unlabelled:
Compared to soy, whey protein is higher in leucine, absorbed quicker and results in a more pronounced increase in muscle protein synthesis.
Objective:
To determine whether supplementation with whey promotes greater increases in muscle mass compared to soy or carbohydrate, we randomized non-resistance-trained men and women into groups who consumed daily isocaloric supplements containing carbohydrate (carb; n = 22), whey protein (whey; n = 19), or soy protein (soy; n = 22).
Methods:
All subjects completed a supervised, whole-body periodized resistance training program consisting of 96 workouts (~9 months). Body composition was determined at baseline and after 3, 6, and 9 months. Plasma amino acid responses to resistance exercise followed by supplement ingestion were determined at baseline and 9 months.
Results:
Daily protein intake (including the supplement) for carb, whey, and soy was 1.1, 1.4, and 1.4 g·kg body mass⁻¹, respectively. Lean body mass gains were significantly (p < 0.05) greater in whey (3.3 ± 1.5 kg) than carb (2.3 ± 1.7 kg) and soy (1.8 ± 1.6 kg). Fat mass decreased slightly but there were no differences between groups. Fasting concentrations of leucine were significantly elevated (20%) and postexercise plasma leucine increased more than 2-fold in whey. Fasting leucine concentrations were positively correlated with lean body mass responses.
Conclusions:
Despite consuming similar calories and protein during resistance training, daily supplementation with whey was more effective than soy protein or isocaloric carbohydrate control treatment conditions in promoting gains in lean body mass. These results highlight the importance of protein quality as an important determinant of lean body mass responses to resistance training.
Objective
The purpose of this double-blind, randomized study was to assess the effects of supplemental whey protein with or without added l-glutamime and branched-chain ainino acids on body mass, body composition, and exercise performance for a 10-week period.
Methods
Sixteen healthy athletic male adults were separated into 2 groups where they received either whey protein 40 g/d (group 1) or a combination of 40 g of whey protein with 5 g of l-glutamine and 3 g of branched-chain ainino acids (leucine, isoleucine, and valine) per day (group 2). Each subject was instructed to follow a diet, created by a registered dietitian, that restricted food protein intake to 1.6 g/kg body weight. In addition, all participants engaged in hypertrophy resistance exercise training under the guidance of an exercise physiologist. At baseline, week 5, and week 10, each subject underwent body composition and exercise performance testing.
Results
Compared with group 1, group 2 gained a significant amount of body mass (1.25 kg; P ≤ 0.05) over the 10 weeks. During the first 5 weeks, group 2 gained a significant amount of fat-free mass (0.72 kg; P = 0.05) compared with group 1. At 10 weeks, group 2 exhibited a trend toward gaining fat-free mass (1.6 kg). No significant changes were noted comparatively for change in percent body fat. In terms of exercise performance (bench press repetitions), group 2 improved significantly (P = 0.001) compared with group 1 after 10 weeks of supplementation. Group 2 also exhibited a trend over 10 weeks compared with group 1 for improvement in leg press repetitions (9.13 vs 5.13).
Conclusions
Results of the present study suggest that whey protein combined with glutamine and branched-chain amino acids, in addition to resistance exercise, leads to improved body composition and exercise performance.
Background
Consumption of moderate amounts of animal-derived protein has been shown to differently influence skeletal muscle hypertrophy during resistance training when compared with nitrogenous and isoenergetic amounts of plant-based protein administered in small to moderate doses. Therefore, the purpose of the study was to determine if the post-exercise consumption of rice protein isolate could increase recovery and elicit adequate changes in body composition compared to equally dosed whey protein isolate if given in large, isocaloric doses.
Methods
24 college-aged, resistance trained males were recruited for this study. Subjects were randomly and equally divided into two groups, either consuming 48 g of rice or whey protein isolate (isocaloric and isonitrogenous) on training days. Subjects trained 3 days per week for 8 weeks as a part of a daily undulating periodized resistance-training program. The rice and whey protein supplements were consumed immediately following exercise. Ratings of perceived recovery, soreness, and readiness to train were recorded prior to and following the first training session. Ultrasonography determined muscle thickness, dual emission x-ray absorptiometry determined body composition, and bench press and leg press for upper and lower body strength were recorded during weeks 0, 4, and 8. An ANOVA model was used to measure group, time, and group by time interactions. If any main effects were observed, a Tukey post-hoc was employed to locate where differences occurred.
Results
No detectable differences were present in psychometric scores of perceived recovery, soreness, or readiness to train (p > 0.05). Significant time effects were observed in which lean body mass, muscle mass, strength and power all increased and fat mass decreased; however, no condition by time interactions were observed (p > 0.05).
Conclusion
Both whey and rice protein isolate administration post resistance exercise improved indices of body composition and exercise performance; however, there were no differences between the two groups.
The purpose of this study was to examine the effects of two different types of protein supplementation on thigh muscle cross-sectional area, blood markers, muscular strength, endurance, and body composition after eight weeks of low- or moderate-volume resistance training in healthy, recreationally trained, college-aged men. One hundred and six men were randomized into five groups: low-volume resistance training with bio-enhanced whey protein (BWPLV; n=22), moderate-volume resistance training with BWP (BWPMV; n=20), moderate-volume resistance training with standard whey protein (SWPMV; n=22), moderate-volume resistance training with a placebo (PLA; n=21), or moderate-volume resistance training with no supplementation (CON; n=21). Except for CON, all groups consumed one shake before and after each exercise session and one each non-training day. The BWPLV, BWPMV, and SWPMV groups received approximately 20g of whey protein per shake, while the BWP groups received 5g additional polyethylene glycosylated (PEG) leucine. Resistance training sessions were performed three times per week for eight weeks. There were no interactions (p>0.05) for muscle strength and endurance variables, body composition, muscle cross-sectional area, and safety blood markers, but main effects for training were observed (p≤0.05). However, Albumin:Globulin ratio for SWPMV was lower (p=0.037) than BWPLV and BWPMV. Relative protein intake (PROREL) indicated a significant interaction (p<0.001) with no differences across groups at pre, however, BWPLV, BWPMV, and SWPMV had a greater intake than PLA or CON at post (p<0.001). The present study indicated that eight weeks of resistance training improved muscle performance and size similarly among groups regardless of supplementation.
There is likely no other dietary component that inspires as much debate, insofar as athletes are concerned, as protein. How much dietary protein is required, optimal, or excessive? Dietary guidelines from a variety of sources have settled on an adequate dietary protein intake for those over the age of 19 of ~0.8-0.9 g protein.kg body weight(-1).d(-1). According to U.S. and Canadian dietary reference intakes (33), the recommended allowance for protein of 0.8 g protein.kg(-1).d(-1) is "the average daily intake level that is sufficient to meet the nutrient requirement of nearly all [~98%] . . . healthy individuals" (p. 22). The panel also stated, "in view of the lack of compelling evidence to the contrary, no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise" (33, p. 661). Currently, no group or groups of scientists involved in establishing dietary guidelines see a need for any statement that athletes or people engaging in regular physical activity require more protein than their sedentary counterparts. Popular magazines, numerous Web sites, trainers, and many athletes decry protein intakes even close to those recommended. Even joint position stands from policy-setting groups state that "protein recommendations for endurance athletes are 1.2 to 1.4 g/kg body weight per day, whereas those for resistance and strength-trained athletes may be as high as 1.6 to 1.7 g/kg body weight per day" (1, p. 1544). The divide between those setting dietary protein requirements and those who might be making practical recommendations for athletes appears substantial, but ultimately, most athletes indicate that they consume protein at levels beyond even the highest recommendations. Thus, one might conclude that any debate on protein "requirements" for athletes is inconsequential; however, a critical analysis of existing and new data reveals novel ideas and concepts that may represent some common ground between these apparently conflicted groups. The goal of this review was to provide a critical and thorough analysis of current data on protein requirements in an attempt to provide some guidance to athletes, trainers, coaches, and sport dietitians on athletes' protein intake. In addition, an effort was made to clearly distinguish between "required" dietary protein, "optimal" intakes, and intakes that are likely "excessive," perhaps not from the standpoint of health, but certainly from the standpoint of potentially compromised performance.
Objective:
To prospectively evaluate the effects of resistance training combined with increased energy intake or protein-supplementation on lean body-mass, resting metabolic-rate (RMR) and cardiovascular risk factors.
Methods:
Twenty-four healthy males (aged 19-32 years) performed resistance exercise for 12 weeks aiming for at least 1 hour training-sessions 3 times a week. The participants were randomized to consume extra protein (33 g whey protein/day) or a meal of fast-food/day (1350 kcal, 41 g protein). Body-composition was measured with Dual-Energy X-ray Absorptiometry (DEXA) and RMR by indirect calorimetry. Fasting blood samples were drawn before and after the 3-month training period and after 12 months.
Results:
The body weight increased from 75.1 ± 6.9 kg to 78.7 ± 7.2 kg (p < 0.0001), without differences between the groups. RMR increased from 1787 ± 143 kcal/24 h to 1954 ± 187 kcal/24 h (p < 0.0001, N = 24), which was more than expected from the increase in lean body-mass (increase from 59.7 ± 4.3 kg to 61.8 ± 4.1 kg p = 0.004). Fasting serum-insulin levels increased in the fast-food group compared with the extra-protein group (p = 0.03). ApoB increased from 0.691 ± 0.14 g/L to 0.768 ± 0.17 g/L, p = 0.004, in the fast-food group only. Long-term follow up after 12 months showed that RMR, body weight, total fat and lean body-masses did not differ from baseline (n = 19).
Conclusions:
Resistance training for 12 weeks increased RMR and lean body-mass similarly when based on either an increased energy-intake or protein supplement. However, the increase in RMR was higher than expected from the increase in lean body-mass. Thus resistance training could potentially decrease the risk of obesity by induction of increased RMR.
A series of complex intracellular networks influence the regulation of skeletal muscle protein turnover. In recent years, studies have examined how cellular regulators of muscle protein turnover modulate metabolic mechanisms contributing to the loss, gain, or conservation of skeletal muscle mass. Exercise and amino acids both stimulate anabolic signaling potentially through several intracellular pathways including the mammalian target of rapamycin complex 1 and the mitogen activated protein kinase cell signaling cascades. As novel molecular regulators of muscle integrity continue to be explored, a contemporary analysis of the literature is required to understand the metabolic mechanisms by which contractile forces and amino acids affect cellular process that contribute to long-term adaptations and preservation of muscle mass. This article reviews the literature related to how exercise and amino acid availability affect cellular regulators of skeletal muscle mass, especially highlighting recent investigations that have identified mechanisms by which contractile forces and amino acids modulate muscle health. Furthermore, this review will explore integrated exercise and nutrition strategies that promote the maintenance of muscle health by optimizing exercise, and amino acid-induced cell signaling in aging adults susceptible to muscle loss.
Background
Owing to the mechanics of anti-doping regulation via the World Anti-Doping Agency's Prohibited List, nutritional supplement use received little attention in comparison to the prevalence of doping. The aims of this study were to investigate supplement use, identify groups of athletes with high levels of supplement use and the prevalence of concomitant use of supplements.
Methods
Survey data from 847 high-performing athletes in the UK were analysed using descriptive statistics. The survey, conducted by UK Sport, consisted of questions regarding knowledge of the prohibited substances, testing procedure, nutritional supplement use and perceptions of the doping problem. The proportion of supplement users and the relative use of each supplement were compared by age, gender and professional status.
Results
Among 874 high-performing athletes in the UK sample, 58.8% of them reported the use of at least one nutritional supplement. Among supplement users, 82.6% used more than one and 11.5% reported use of more than five nutritional supplements. Of the 9 supplements listed, multivitamins (72.6%) and vitamin C (70.7%) were used most, followed by creatine (36.1%), whey protein (31.7%), echinacea (30.9%), iron (29.9%) and caffeine (23.7%). Less than 11% reported the use of magnesium or ginseng. Creatine use was typically associated with males regardless of status and across all ages, whereas iron was characteristically used by females. A 'typical' supplement user is male, between 24 and 29 years of age, involved in professional sport and using a combination of supplements. Male professional players between age 30 and 34 years, and female non-professional athletes between 24 and 29 years of age also represented a considerable proportion of supplement users. Athletes older than 40 years of age were practically non-users. Concomitant use of supplements is characteristic of male users more than females.
Conclusion
As supplement use has been previously shown to increase the probability of prohibited substance use, groups exhibiting high use of nutritional supplements should be monitored. Future research should incorporate a wide range of supplements and enquire about the daily amount ingested. In addition to tutoring, preventive measures should incorporate offering acceptable and healthy alternatives for assisted performance enhancement.
Our purpose was to assess muscular adaptations during 6 weeks of resistance training in 36 males randomly assigned to supplementation with whey protein (W; 1.2 g/kg/day), whey protein and creatine monohydrate (WC; 0.1 g/kg/day), or placebo (P; 1.2 g/kg/day maltodextrin). Measures included lean tissue mass by dual energy x-ray absorptiometry, bench press and squat strength (1-repetition maximum), and knee extension/flexion peak torque. Lean tissue mass increased to a greater extent with training in WC compared to the other groups, and in the W compared to the P group (p < .05). Bench press strength increased to a greater extent for WC compared to W and P (p < .05). Knee extension peak torque increased with training for WC and W (p < .05), but not for P. All other measures increased to a similar extent across groups. Continued training without supplementation for an additional 6 weeks resulted in maintenance of strength and lean tissue mass in all groups. Males that supplemented with whey protein while resistance training demonstrated greater improvement in knee extension peak torque and lean tissue mass than males engaged in training alone. Males that supplemented with a combination of whey protein and creatine had greater increases in lean tissue mass and bench press than those who supplemented with only whey protein or placebo. However, not all strength measures were improved with supplementation, since subjects who supplemented with creatine and/or whey protein had similar increases in squat strength and knee flexion peak torque compared to subjects who received placebo.
Sustained periods of negative energy balance decrease body mass due to losses of both fat and skeletal muscle mass. Decreases in skeletal muscle mass are associated with a myriad of negative consequences, including suppressed basal metabolic rate, decreased protein turnover, decreased physical performance, and increased risk of injury. Decreases in skeletal muscle mass in response to negative energy balance are due to imbalanced rates of muscle protein synthesis and degradation. However, the underlying physiological mechanisms contributing to the loss of skeletal muscle during energy deprivation are not well described. Recent studies have demonstrated that consuming dietary protein at levels above the current recommended dietary allowance (0.8 g · kg(-1) · d(-1)) may attenuate the loss of skeletal muscle mass by affecting the intracellular regulation of muscle anabolism and proteolysis. However, the specific mechanism by which increased dietary protein spares skeletal muscle through enhanced molecular control of muscle protein metabolism has not been elucidated. This article reviews the available literature related to the effects of negative energy balance on skeletal muscle mass, highlighting investigations that assessed the influence of varying levels of dietary protein on skeletal muscle protein metabolism. Further, the molecular mechanisms that may contribute to the regulation of skeletal muscle mass in response to negative energy balance and alterations in dietary protein level are described.
The effects of 28 days of heavy resistance training while ingesting the pre- and post-workout supplements, NO-Shotgun® and NO-Synthesize® were determined on body composition, muscle strength and mass, markers of protein synthesis, and clinical safety markers.
Nineteen non-resistance-trained males participated in a resistance training program 4 times/week for 28 days while either ingesting 27 g/day of carbohydrate (CARB) or NO-Shotgun® 30 min pre-exercise and 27 g/day of carbohydrate or NO- Synthesize® 30 min post-exercise (NOSS). Data were analyzed with separate 2 × 2 ANOVA (p < 0.05).
Total body mass was increased in both groups (p = 0.001), but not different between groups. Fat mass was unchanged with CARB, but NOSS decreased fat mass (p = 0.026). Both groups increased fat-free mass (p = 0.001); however, the increases were greater with NOSS (p = 0.023). NOSS underwent greater increases in upper-body (p = 0.023) and lower-body (p = 0.035) strength than CARB. Myofibrillar protein significantly increased in both groups (p = 0.041), with NOSS being greater than CARB (p = 0.049). All of the MHC isoforms were significantly increased in both groups; however, NOSS was greater than CARB for MHC 1 (p = 0.013) and MHC 2A (p = 0.046). All of the myogenic regulatory factors were significantly increased in both groups; however, NOSS was greater than CARB for Myo-D (p = 0.038) and MRF-4 (p = 0.001). For the whole blood and serum clinical chemistry markers, all variables remained within normal clinical ranges.
Heavy resistance training for 28 days, with NO-Shotgun® and NO-Synthesize® ingested before and after exercise, respectively, significantly improved body composition and increased muscle mass and performance without abnormally impacting any of the clinical chemistry markers.
Carbohydrate-protein supplementation has been found to increase the rate of training adaptation when provided postresistance exercise. The present study compared the effects of a carbohydrate and protein supplement in the form of chocolate milk (CM), isocaloric carbohydrate (CHO), and placebo on training adaptations occurring over 4.5 weeks of aerobic exercise training. Thirty-two untrained subjects cycled 60 min/d, 5 d/wk for 4.5 wks at 75-80% of maximal oxygen consumption (VO(2) max). Supplements were ingested immediately and 1 h after each exercise session. VO(2) max and body composition were assessed before the start and end of training. VO(2) max improvements were significantly greater in CM than CHO and placebo. Greater improvements in body composition, represented by a calculated lean and fat mass differential for whole body and trunk, were found in the CM group compared to CHO. We conclude supplementing with CM postexercise improves aerobic power and body composition more effectively than CHO alone.
The effects of timed ingestion of high-quality protein before and after resistance exercise are not well known. In this study, young men were randomized to protein (n = 11), placebo (n = 10) and control (n = 10) groups. Muscle cross-sectional area by MRI and muscle forces were analyzed before and after 21 weeks of either heavy resistance training (RT) or control period. Muscle biopsies were taken before, and 1 and 48 h after 5 x 10 repetition leg press exercise (RE) as well as 21 weeks after RT. Protein (15 g of whey both before and after exercise) or non-energetic placebo were provided to subjects in the context of both single RE bout (acute responses) as well as each RE workout twice a week throughout the 21-week-RT. Protein intake increased (P < or = 0.05) RT-induced muscle cross-sectional area enlargement and cell-cycle kinase cdk2 mRNA expression in the vastus lateralis muscle suggesting higher proliferating cell activation response with protein supplementation. Moreover, protein intake seemed to prevent 1 h post-RE decrease in myostatin and myogenin mRNA expression but did not affect activin receptor IIb, p21, FLRG, MAFbx or MyoD expression. In conclusion, protein intake close to resistance exercise workout may alter mRNA expression in a manner advantageous for muscle hypertrophy.
World records for athletic events continue to improve and in the search for superior methods to gain a competitive edge, coaches and athletes are constantly searching for the latest "magic bullet". Although it is assumed that optimal adaptation to the demands of repeated training sessions requires a diet that can sustain muscle energy reserves, this premise does not consider the unsolved longstanding question of whether it is a lack or a surplus of a substrate that triggers the training adaptation. As such, recent scientific enquiry has re-focused attention on the role of substrate availability before, during, and after training to amplify the training adaptation. There has also been a resurgence of interest in the potential for protein ingestion to improve performance and/or promote training-induced adaptations in skeletal muscle. Altitude training (real or simulated) is now an accepted part of competition preparation for many athletic events, and such interventions attract their own nutritional issues. These and other diet-training interactions with the potential to alter training adaptation and performance are discussed.
The purpose of this study was to compare the effects of supplementation with Gaspari Nutrition's SOmaxP Maximum Performance™ (SOmaxP) versus a comparator product (CP) containing an equal amount of creatine (4 g), carbohydrate (39 g maltodextrin), and protein (7 g whey protein hydrolysate) on muscular strength, muscular endurance, and body composition during nine weeks of intense resistance training.
Using a prospective, randomized, double-blind design, 20 healthy men (mean ± SD age, height, weight, % body fat: 22.9 ± 2.6 y, 178.4 ± 5.7 cm, 80.5 ± 6.6 kg, 16.6 ± 4.0%) were matched for age, body weight, resistance training history, bench press strength, bench press endurance, and percent body fat and then randomly assigned via the ABBA procedure to ingest 1/2 scoop (dissolved in 15 oz water) of SOmaxP or CP prior to, and another 1/2 scoop (dissolved in 15 oz water) during resistance exercise. Body composition (DEXA), muscular performance (1-RM bench press and repetitions to failure [RTF: 3 sets × baseline body weight, 60-sec rest between sets]), and clinical blood chemistries were measured at baseline and after nine weeks of supplementation and training. Subjects were required to maintain their normal dietary habits and follow a specific, progressive overload resistance training program (4-days/wk, upper body/lower body split) during the study. An intent-to-treat approach was used and data were analyzed via ANCOVA using baseline values as the covariate. Statistical significance was set a priori at p ≤ 0.05.
When adjusted for initial differences, significant between group post-test means were noted in: 1-RM bench press (SOmaxP: 133.3 ± 1.3 kg [19.8% increase] vs. CP: 128.5 ± 1.3 kg [15.3% increase]; p < 0.019); lean mass (SOmaxP: 64.1 ± 0.4 kg [2.4% increase] vs. 62.8 ± 0.4 kg [0.27% increase], p < 0.049); RTF (SOmaxP: 33.3 ± 1.1 reps [44.8% increase] vs. 27.8 ± 1.1 reps [20.9% increase], p < 0.004); and fat mass (SOmaxP: 12.06 ± 0.53 kg [9.8% decrease] vs. 13.90 ± 0.53 kg [4.1% increase], p < 0.024). No statistically significant differences in vital signs (heart rate, systolic and diastolic blood pressures) or clinical blood chemistries were noted.
These data indicate that compared to CP, SOmaxP administration augments and increases gains in lean mass, bench press strength, and muscular performance during nine weeks of intense resistance training. Studies designed to confirm these results and clarify the molecular mechanisms by which SOmaxP exerts the observed salutary effects have begun. Both SOmaxP and the CP were well-tolerated, and no supplement safety issues were identified.
A randomized, double-blind, placebo controlled design was used in which 13 elite female rowers. all of whom had competed at World Championships, were supplemented with 60 g . day(-1) of either bovine colostrum (BC; n = 6) or concentrated whey protein powder (WP; n = 7) during 9 weeks of pre-competition training. All subjects undertook the study as a group and completed the same training program. Prior to, and after 9 weeks of supplementation and training, subjects completed an incremental rowing test (ROW 1) on a rowing ergometer consisting of 3 X 4-min submaximal workloads and a 4-min maximal effort (4max), each separated by a 1-min recovery period. The rowing test was repeated after a 15-min period of passive recovery (ROW2). The 4max for ROW1 provided a measure of performance, and the difference between the 4max efforts of ROW1 and ROW2 provided an index of recovery. Blood lactate concentrations and pH measured prior to exercise and at the end of each workload were used to estimate blood buffer capacity (beta). Food intake was recorded daily for dietary analysis. There were no differences in macronutrient intakes (p > .56) or training volumes (p > .99) between BC and WP during the study period. Rowing performance (distance rowed and work done) during 4max of ROW2 was less than ROW1 at baseline (p < .05) but not different between groups (P > .05). Performance increased in both rows by Week 9 (p < .001), with no difference between groups (p >.75). However, the increase was greatest in ROW2 (p < .05), such that by Week 9 there was no longer a difference in performance between the two rows in either group (p >.05). beta was not different between groups for ROW1 at baseline (BC 38.3 +/- 5.0, WP 38.2 +/- 7.2 slykes; p > .05) but was higher in BC by Week 9 (BC 40.8 +/- 5.9, WP 33.4 +/- 5.3 slykes; p < .05). beta for ROW2 followed the same pattern of change as for ROW I. We conclude that supplementation with BC improves beta, but not performance, in elite female rowers. It was not possible to determine whether beta had any effect on recovery.
Different dietary proteins affect whole body protein anabolism and accretion and therefore, have the potential to influence results obtained from resistance training. This study examined the effects of supplementation with two proteins, hydrolyzed whey isolate (WI) and casein (C), on strength, body composition, and plasma glutamine levels during a 10 wk, supervised resistance training program. In a double-blind protocol, 13 male, recreational bodybuilders supplemented their normal diet with either WI or C (1.5 gm/kg body wt/d) for the duration of the program. Strength was assessed by 1-RM in three exercises (barbell bench press, squat, and cable pull-down). Body composition was assessed by dual energy X-ray absorptiometry. Plasma glutamine levels were determined by the enzymatic method with spectrophotometric detection. All assessments occurred in the week before and the week following 10 wk of training. Plasma glutamine levels did not change in either supplement group following the intervention. The WI group achieved a significantly greater gain (P < 0.01) in lean mass than the C group (5.0 +/- 0.3 vs. 0.8 +/- 0.4 kg for WI and C, respectively) and a significant (P < 0.05) change in fat mass (-1.5 +/- 0.5 kg) compared to the C group (+0.2 +/- 0.3 kg). The WI group also achieved significantly greater (P < 0.05) improvements in strength compared to the C group in each assessment of strength. When the strength changes were expressed relative to body weight, the WI group still achieved significantly greater (P < 0.05) improvements in strength compared to the C group.