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... Cr can be endogenously synthesized from amino acids in the kidney and liver, producing about 1-3 g/day in the body [16]. It is a proenergetic, as its major function is to form phosphor-creatine which when acted upon by creatine kinase can transfer the high energy phosphate to ADP creating ATP which provides energy [16,17]. Previous studies have shown that Cr elevates IGF-1 mRNA expression levels in skeletal muscle in adult humans [18,19]. ...
... Additionally, Cr supplementation protects against mitochondrial mutagenesis as well as increases in matrix metalloproteinase-1 in response to UVA [39]. Data from other cell types provided some premise for testing the ability of pro-energetics Cr and NAM to block fibroblast senescence [17,24,25,38,40,41]. In particular, low levels of Cr in disease states including in kidney dialysis patients have been linked to overall poor health [41,42]. ...
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Dermal fibroblasts provide structural support by producing collagen and other structural/support proteins beneath the epidermis. Fibroblasts also produce insulin-like growth factor-1 (IGF-1), which binds to the IGF-1 receptors (IGF-1Rs) on keratinocytes to activate signaling pathways that regulate cell proliferation and cellular responses to genotoxic stressors like ultraviolet B radiation. Our group has determined that the lack of IGF-1 expression due to fibroblast senescence in the dermis of geriatric individuals is correlated with an increased incidence of skin cancer. The present studies tested the hypothesis that pro-energetics creatine monohydrate (Cr) and nicotinamide (NAM) can protect normal dermal human fibroblasts (DHF) against experimentally induced senescence. To that end, we used an experimental model of senescence in which primary DHF are treated with hydrogen peroxide (H2O2) in vitro, with senescence measured by staining for beta-galactosidase activity, p21 protein expression, and senescence associated secretory phenotype cytokine mRNA levels. We also determined the effect of H2O2 on IGF-1 mRNA and protein expression. Our studies indicate that pretreatment with Cr or NAM protects DHF from the H2O2-induced cell senescence. Treatment with pro-energetics post-H2O2 had no effect. Moreover, these agents also inhibited reactive oxygen species generation from H2O2 treatment. These studies suggest a potential strategy for protecting fibroblasts in geriatric skin from undergoing stress-induced senescence, which may maintain IGF-1 levels and therefore limit carcinogenesis in epidermal keratinocytes.
... La cantidad total de Cr en el músculo es de 120 mmol/kg de media para personas de 70 kg, pudiendo llegar a haber niveles de 160 mmol/kg en individuos con misma masa corporal [64]. La mayoría de Cr se encuentra en el músculo esquelético (~95%), mientras que el ~5% restante se encuentra en cerebro y testículos [65,66]. Respecto a la Cr en el músculo, esta se divide en fosofocreatina (PCr) y Cr libre, ocupando la PCr dos tercios del total y la Cr libre el tercio restante [62]. ...
... Estructura química y vía bioquímica para la síntesis de Cr [62,66] Sin embargo, la síntesis de Cr no es suficiente para tener los depósitos de Cr normales, ya que el cuerpo necesita entre 1 y 3 gramos de Cr. Aproximadamente, la mitad de la Cr diaria necesaria se obtiene a través de la dieta [68,69]. ...
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El monohidrato de creatina (CrM) y el β-hidroxi β-metilbutirato (HMB) son suplementos deportivos ampliamente estudiados. Sin embargo, no está claro cómo actúan cuando se utilizan conjuntamente en el ámbito deportivo. Hay que añadir que la incógnita es todavía mayor, cuando hablamos de un deporte de carácter predominantemente aeróbico como el remo. Los objetivos de esta tesis han sido: 1) determinar mediante una revisión sistemática la eficacia de mezclar CrM más HMB en comparación con sus efectos aislados sobre el rendimiento deportivo, la composición corporal, los marcadores de daño muscular inducidos por el ejercicio (EIMD) y las hormonas anabólico-catabólicas. 2) determinar la eficacia y el grado de potenciación de 10 semanas de suplementación con CrM más HMB en el rendimiento deportivo, que se midió mediante una prueba incremental en remeros tradicionales de élite masculinos. 3) determinar el efecto y el grado de potenciación de 10 semanas de suplementación con CrM más HMB en los EIMD y hormonas anabólicas/catabólicas. En base a los objetivos planteados, los principales resultados de la tesis indican que: 1) La combinación de CrM más 3 g/día de HMB durante 1–6 semanas podría producir efectos positivos en el rendimiento deportivo (fuerza y rendimiento anaeróbico) y durante 4 semanas en la composición corporal (aumento de grasa masa libre y disminución de la masa grasa). 2) La ingesta de CrM más HMB durante 10 semanas mostró un efecto sinérgico sobre la potencia aeróbica durante una prueba incremental. 3) La combinación de CrM más HMB presentó un efecto sinérgico sobre la testosterona y la ratio testosterona/cortisol y un efecto antagonista sobre el cortisol en comparación con la suma de la suplementación individual o aislada. Las conclusiones obtenidas en la presente tesis doctoral indican que la combinación de estos dos suplementos puede ser de gran ayuda para los profesionales que rodean al deportista para mejorar el rendimiento aeróbico y la recuperación.
... It can also be taken into the body through food synthesized from essential and nonessential amino acids (33). Although creatine is mostly found in skeletal muscles (95%) in the body, it is also found in certain amounts (5%) in the brain and testicles (43). Although it has different types structurally, the most widely used and preferred type of creatine is creatine monohydrate (CrM) (37). ...
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Creatine, which is a popular ergogenic aid, is shown among the most effective methods used as a performance enhancer in athletes. The aim of this review is to summarize the current publications to show the uses and effects of creatine in exercise. In the present study prepared in a systematic review style, full-text articles about creatine use published in Science Citation Index (SCI), SCI-Expanded, and PubMed/MEDLINE databases' journals between 2010 and 2021 were examined. The searching was performed by "creatine", "creatine monohydrate" and "creatine supplementation" keywords. Data from 46 studies showed that creatine loading in individuals who train during high intensity and short term exercise forms affect performance positively, develop muscle mass/strength and increase muscle creatine phosphate (PCr) stores. It was also found that creatine supplement applied with strength training in elderly individuals increased muscle mass, muscle strength, and movement capacity. It is determined that there is no definitive and clear procedure regarding the usage dosage for creatine. In addition, though some studies have reported that creatine use has a positive effect on cognitive performance, a definite judgment has not been reached. Consequently, it has been demonstrated that creatine supplementation is an effective ergogenic aid for the development of muscle and strength for athletes of all levels. The increase in the number of studies on the creatine usage dosage to be examined in different athlete profiles may lead to a decrease in the contradictions about the usage procedure.
... Creatine is a naturally occurring non-protein nitrogen compound synthesised in the liver and kidney from precursor amino acids, arginine, glycine, and methionine. Most of the body's Cr is found in muscle (95%), of which two-thirds are stored as phosphorylcreatine (PCr), the remaining third as free Cr [3], with less than 5% found in other tissues, such as the brain and testes [4]. In a seminal study by Harris et al. (1992), it was demonstrated for the first time in humans that Cr supplementation, at varying doses of 20-30 g/day, ingested over several individual 5 g doses throughout the day, could increase total intramuscular Cr content (TCr = PCr + Cr) by as much as 20% [5]. ...
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Creatine has been considered an effective ergogenic aid for several decades; it can help athletes engaged in a variety of sports and obtain performance gains. Creatine supplementation increases muscle creatine stores; several factors have been identified that may modify the intramuscular increase and subsequent performance benefits, including baseline muscle Cr content, type II muscle fibre content and size, habitual dietary intake of Cr, aging, and exercise. Timing of creatine supplementation in relation to exercise has recently been proposed as an important consideration to optimise muscle loading and performance gains, although current consensus is lacking regarding the ideal ingestion time. Research has shifted towards comparing creatine supplementation strategies pre-, during-, or post-exercise. Emerging evidence suggests greater benefits when creatine is consumed after exercise compared to pre-exercise, although methodological limitations currently preclude solid conclusions. Furthermore, physiological and mechanistic data are lacking, in regard to claims that the timing of creatine supplementation around exercise moderates gains in muscle creatine and exercise performance. This review discusses novel scientific evidence on the timing of creatine intake, the possible mechanisms that may be involved, and whether the timing of creatine supplementation around exercise is truly a real concern.
... The first phase is a loading phase in which an individual ingests 20 g d −1 in four 5 g doses for five to seven days, followed by a maintenance dose of 3-5 g d −1 of CR for at least a month, and often much longer [2,17,[24][25][26]. During the loading phase, total muscular CR stores have been reported to increase between 20 and 40% [27,28], with reported side effects limited to cramping and bloating during the loading phase [29]. It is important to note that approximately 20-30% of individuals are non-responders to CR supplementation, which has been defined by Greenhaff et al. as individuals with changes in CR stores of <10 mmol kg −1 dry weight (dw) following the loading phase [30]. ...
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The use of dietary supplements has become increasingly common over the past 20 years. Whereas supplements were formerly used mainly by elite athletes, age and fitness status no longer dictates who uses these substances. Indeed, many nutritional supplements are recommended by health care professionals to their patients. Creatine (CR) is a widely used dietary supplement that has been well-studied for its effects on performance and health. CR also aids in recovery from strenuous bouts of exercise by reducing inflammation. Although CR is considered to be very safe in recommended doses, a caveat is that a preponderance of the studies have focused upon young athletic individuals; thus there is limited knowledge regarding the effects of CR on children or the elderly. In this review, we examine the potential of CR to impact the host outside of the musculoskeletal system, specifically, the immune system, and discuss the available data demonstrating that CR can impact both innate and adaptive immune responses, together with how the effects on the immune system might be exploited to enhance human health.
... Creatine is a naturally occurring nonprotein amino acid that is primarily found in red meat and seafood (Kreider et al., 2017). Creatine is predominately found in skeletal muscle (Kreider & Jung, 2011), playing an important role in energy production via the adenosine triphosphate-phosphocreatine (ATP-PC) system. During daily life, small amounts of intramuscular creatine are degraded and excreted; as a result, adults need to consume 1-3 g/day to maintain normal stores (Kreider et al., 2017). ...
Article
Elite sprint performances typically peak during an athlete’s 20s and decline thereafter with age. The mechanisms underpinning this sprint performance decline are often reported to be strength-based in nature with reductions in strength capacities driving increases in ground contact time and decreases in stride lengths and frequency. However, an as-of-yet underexplored aspect of Masters sprint performance is that of age-related degradation in neuromuscular infrastructure, which manifests as a decline in both strength and movement coordination. Here, the authors explore reductions in sprint performance in Masters athletes in a holistic fashion, blending discussion of strength and power changes with neuromuscular alterations along with mechanical and technical age-related alterations. In doing so, the authors provide recommendations to Masters sprinters—and the aging population, in general—as to how best to support sprint ability and general function with age, identifying nutritional interventions that support performance and function and suggesting useful programming strategies and injury-reduction techniques.
... Creatine is a naturally occurring nonprotein amino acid that is primarily found in red meat and seafood (Kreider et al., 2017). Creatine is predominately found in skeletal muscle (Kreider & Jung, 2011), playing an important role in energy production via the adenosine triphosphate-phosphocreatine (ATP-PC) system. During daily life, small amounts of intramuscular creatine are degraded and excreted; as a result, adults need to consume 1-3 g/day to maintain normal stores (Kreider et al., 2017). ...
Article
Elite sprint performances typically peak during an athlete’s twenties, and decline thereafter with age. The mechanisms underpinning this sprint performance decline are often reported to be strength-based in nature, with reductions in strength capacities driving increases in ground contact time and decreases in stride lengths and frequency. However, an as-of-yet under-explored aspect of Masters sprint performance is that of age-related degradation in neuromuscular infrastructure, which manifests as both declining strength and movement coordination. Here, we explore reductions in sprint performance in Masters athletes in an holistic fashion, blending discussion of strength and power changes with neuromuscular alterations, along with mechanical and technical age-related alterations. In doing so, we provide recommendations to Masters sprinters—and the aging population in general—as to how best to support sprint ability and general function with age, identifying nutritional interventions that support performance and function, and suggest useful programming strategies and injury-reduction techniques.
... & Improved performance in sets of high-intensity muscle contractions & Increased muscle mass and strength adaptations from training & Enhanced recovery & Greater training tolerance [346] Creatine supplementation has been shown to be safe and effective for improving accrual of LM and improving strength in older people [276]. A study by Aguiar et al. [347] in healthy women (mean age 65 years) undergoing a 12-week RE program reported that those supplementing with 5 g of creatine per day experienced a greater improvement in bench press, knee extension, and bicep curl 1RM strength and improvements in functional performance, as well as a greater increase in muscle mass (+ 2.8 kg) than the control group. ...
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The COVID-19 pandemic is an extraordinary global emergency that has led to the implementation of unprecedented measures in order to stem the spread of the infection. Internationally, governments are enforcing measures such as travel bans, quarantine, isolation, and social distancing leading to an extended period of time at home. This has resulted in reductions in physical activity and changes in dietary intakes that have the potential to accelerate sarcopenia, a deterioration of muscle mass and function (more likely in older populations), as well as increases in body fat. These changes in body composition are associated with a number of chronic, lifestyle diseases including cardiovascular disease (CVD), diabetes, osteoporosis, frailty, cognitive decline, and depression. Furthermore, CVD, diabetes, and elevated body fat are associated with greater risk of COVID-19 infection and more severe symptomology, underscoring the importance of avoiding the development of such morbidities. Here we review mechanisms of sarcopenia and their relation to the current data on the effects of COVID-19 confinement on physical activity, dietary habits, sleep, and stress as well as extended bed rest due to COVID-19 hospitalization. The potential of these factors to lead to an increased likelihood of muscle loss and chronic disease will be discussed. By offering a number of home-based strategies including resistance exercise, higher protein intakes and supplementation, we can potentially guide public health authorities to avoid a lifestyle disease and rehabilitation crisis post-COVID-19. Such strategies may also serve as useful preventative measures for reducing the likelihood of sarcopenia in general and in the event of future periods of isolation.
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In 2011, we published a paper providing an overview about the bioavailability, efficacy, and regulatory status of creatine monohydrate (CrM), as well as other “novel forms” of creatine that were being marketed at the time. This paper concluded that no other purported form of creatine had been shown to be a more effective source of creatine than CrM, and that CrM was recognized by international regulatory authorities as safe for use in dietary supplements. Moreover, that most purported “forms” of creatine that were being marketed at the time were either less bioavailable, less effective, more expensive, and/or not sufficiently studied in terms of safety and/or efficacy. We also provided examples of several “forms” of creatine that were being marketed that were not bioavailable sources of creatine or less effective than CrM in comparative effectiveness trials. We had hoped that this paper would encourage supplement manufacturers to use CrM in dietary supplements given the overwhelming efficacy and safety profile. Alternatively, encourage them to conduct research to show their purported “form” of creatine was a bioavailable, effective, and safe source of creatine before making unsubstantiated claims of greater efficacy and/or safety than CrM. Unfortunately, unsupported misrepresentations about the effectiveness and safety of various “forms” of creatine have continued. The purpose of this critical review is to: (1) provide an overview of the physiochemical properties, bioavailability, and safety of CrM; (2) describe the data needed to substantiate claims that a “novel form” of creatine is a bioavailable, effective, and safe source of creatine; (3) examine whether other marketed sources of creatine are more effective sources of creatine than CrM; (4) provide an update about the regulatory status of CrM and other purported sources of creatine sold as dietary supplements; and (5) provide guidance regarding the type of research needed to validate that a purported “new form” of creatine is a bioavailable, effective and safe source of creatine for dietary supplements. Based on this analysis, we categorized forms of creatine that are being sold as dietary supplements as either having strong, some, or no evidence of bioavailability and safety. As will be seen, CrM continues to be the only source of creatine that has substantial evidence to support bioavailability, efficacy, and safety. Additionally, CrM is the source of creatine recommended explicitly by professional societies and organizations and approved for use in global markets as a dietary ingredient or food additive.
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Although creatine has been mostly studied as an ergogenic aid for exercise, training, and sport, several health and potential therapeutic benefits have been reported. This is because creatine plays a critical role in cellular metabolism, particularly during metabolically stressed states, and limitations in the ability to transport and/or store creatine can impair metabolism. Moreover, increasing availability of creatine in tissue may enhance cellular metabolism and thereby lessen the severity of injury and/or disease conditions, particularly when oxygen availability is compromised. This systematic review assesses the peer-reviewed scientific and medical evidence related to creatine’s role in promoting general health as we age and how creatine supplementation has been used as a nutritional strategy to help individuals recover from injury and/or manage chronic disease. Additionally, it provides reasonable conclusions about the role of creatine on health and disease based on current scientific evidence. Based on this analysis, it can be concluded that creatine supplementation has several health and therapeutic benefits throughout the lifespan.
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