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Phosphorylation of Akt at Ser473 2 h following EAA, RE, and COM in healthy younger (n = 7) and older (n = 7) individuals. The symbol (#) denotes statistical significance between age groups. Data are means ± SEM.
Source publication
We investigated the effects of ingesting a leucine-enriched essential amino acid (EAA) gel alone or combined with resistance exercise (RE) versus RE alone (control) on plasma aminoacidemia and intramyocellular anabolic signaling in healthy younger (28 ± 4 years) and older (71 ± 3 years) adults. Blood samples were obtained throughout the three trial...
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Amino acids are needed for general bodily function and well-being. Despite their importance, augmentation in their serum concentration is closely related to metabolic disorder, insulin resistance (IR), or worse, diabetes mellitus. Essential amino acids such as the branched-chain amino acids (BCAAs) have been heavily studied as a plausible biomarker...
Abstract
Objective
Profound metabolic alterations characterize cancer development and, beyond glucose addiction, amino acid (AA) dependency is now recognized as a hallmark of tumour growth. Therefore, targeting the metabolic addiction of tumours by reprogramming their substrate utilization is an attractive therapeutic strategy. We hypothesized tha...
Low‐protein (LP) diets are associated with a decreased risk of diabetes in humans, and promote leanness and glycaemic control in both rodents and humans. While the effects of an LP diet on glycaemic control are mediated by reduced levels of the branched‐chain amino acids, we have observed that reducing dietary levels of the other six essential amin...
Cheddar cheese is a protein-dense whole food and high in leucine content. However, no information is known about the acute blood amino acid kinetics and protein anabolic effects in skeletal muscle in healthy adults. Therefore, we conducted a crossover study in which men and women (n = 24; ~27 years, ~23 kg/m2) consumed cheese (20 g protein) or an i...
Citations
... The analysis of micronutrients in nutritional collections is very interesting from a dietary and business perspective. This kind of research is essential for comprehending the contents of foods and environmental samples given their harmfulness and crucial characteristics [23]. ...
Background: The assessment of the extraction yield and nutritional content of Boswellia carterii extracts, including vitamins and trace elements, is significant. Objective: The study aims to identify phytochemical compounds present, and concluding on the plant’s potential health benefits and dietary contributions. Methods: The present study was conducted to extract the vitamins, trace elements and phytochemical constituents of Boswellia carterii leaves extracts using distilled water, ETOH (99%), and Ethylacetate by soxhlet. The yield of extracts was (18.361g/100g distilled water) while (29.322g/100g ETOH) and the Ethylacetate was found to be (27. 312g/100g). Different types of vitamins were estimated in all extracts utilizing HPLC. Results: Vitamins showed interesting results by revealing (A, B6, and B12). Vita. B12 is the most abundant in Alcohol extract, whereas vita. B12 is the most abundant in aqueous extract, and vita. B12 is the most abundant in ethylacetate compared with vitamin A, and B6. These findings call for more research into the vitamins in Boswellia carterii and their antioxidant relevance in therapeutic herbal medicine. Different metal ions were measured using FAAS (Cd, Co, Cr, Cu, Mn, Ni, Pb, Se, and Zn). The results of the qualitative detection of all extracts indicated the existence of Alkaloids, Steroids, Terpenes, Phenols, Carbohydrates, Glycosides, Proteins, Saponins, Tannins, and Flavonoids. Conclusions: The results of the qualitative detection of all extracts indicated the existence of Alkaloids, Steroids, Terpenes, Phenols, Carbohydrates, Glycosides, Proteins, Saponins, Tannins, and Flavonoids.
... The effects of EAA and resistance exercise upon upregulation of anabolic signaling is consistent with aging. EAAs plus resistance exercise increases peripheral EAA concentrations equally in both young and older subjects [72]. Regardless of age, increases in mTOR (Ser2481) and ribosomal protein S6 (Ser235/236) were demonstrated with the combined treatment [72], suggesting an improved muscle sensitivity to the combined stimuli. ...
... EAAs plus resistance exercise increases peripheral EAA concentrations equally in both young and older subjects [72]. Regardless of age, increases in mTOR (Ser2481) and ribosomal protein S6 (Ser235/236) were demonstrated with the combined treatment [72], suggesting an improved muscle sensitivity to the combined stimuli. further, post-exercise EAA administration in older men leads to an increase in satellite cell proliferation [73]. ...
Position Statement: The International Society of Sports Nutrition (ISSN) presents this position based on a critical examination of literature surrounding the effects of essential amino acid (EAA) supplementation on skeletal muscle maintenance and performance. This position stand is intended to provide a scientific foundation to athletes, dietitians, trainers, and other practitioners as to the benefits of supplemental EAA in both healthy and resistant (aging/clinical) populations. EAAs are crucial components of protein intake in humans, as the body cannot synthesize them. The daily recommended intake (DRI) for protein was established to prevent deficiencies due to inadequate EAA consumption. The following conclusions represent the official position of the Society: 1. Initial studies on EAAs’ effects on skeletal muscle highlight their primary role in stimulating muscle protein synthesis (MPS) and turnover. Protein turnover is critical for replacing degraded or damaged muscle proteins, laying the metabolic foundation for enhanced functional performance. Consequently, research has shifted to examine the effects of EAA supplementation – with and without the benefits of exercise – on skeletal muscle maintenance and performance. 2. Supplementation with free-form EAAs leads to a quick rise in peripheral EAA concentrations, which in turn stimulates MPS. 3. The safe upper limit of EAA intake (amount), without inborn metabolic disease, can easily accommodate additional supplementation. 4. At rest, stimulation of MPS occurs at relatively small dosages (1.5–3.0 g) and seems to plateau at around 15–18 g. 5. The MPS stimulation by EAAs does not require non-essential amino acids. 6. Free-form EAA ingestion stimulates MPS more than an equivalent amount of intact protein. 7. Repeated EAA-induced MPS stimulation throughout the day does not diminish the anabolic effect of meal intake. 8. Although direct comparisons of various formulas have yet to be investigated, aging requires a greater proportion of leucine to overcome the reduced muscle sensitivity known as “anabolic resistance.” 9. Without exercise, EAA supplementation can enhance functional outcomes in anabolic-resistant populations. 10. EAA requirements rise in the face of caloric deficits. During caloric deficit, it’s essential to meet whole-body EAA requirements to preserve anabolic sensitivity in skeletal muscle.
... Studies have shown that peak protein synthesis happens 2 h postmeal, and until recently, the recommendations have been to distribute protein intake across the meals, such as 0.4/kg/meal or 30 g/meal, to counteract anabolic resistance and limit muscle mass loss (41)(42)(43). Leucine is recognized as an anabolic stimulus and together with exercise acts through the mechanistic target of the rapamycin complex 1 (mTORC1) pathway in enhancing muscle protein synthesisand immunomodulatory function and reducing muscle protein breakdown (44,45). Participants in our study received leucine-enriched whey and soy protein, and while we have no information on the timings of leucineenriched protein supplementation, participants in the Nu+Ex group showed improvement in physical function, inflammation, and body composition measures. ...
Background
Exercise and a protein-enriched diet are essential for muscle protein synthesis, cellular growth, mitochondrial function, and immune function. The U.S. Food and Nutrition Board's current guideline on recommended dietary allowance for protein in older adults is 0.8 g/kg per day, which may not be sufficient in vulnerable pre-frail older adults.
Aims
This study aimed to evaluate the impact of leucine-enriched protein supplementation with or without exercise over 3 months in pre-frail older adults who consumed ≤1 g/kg/day of protein on improving (i) physical function, (ii) body composition measures, and (iii) inflammatory biomarkers such as interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α).
Methods
A non-randomized cluster quasi-experimental study guided by the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist of 178 pre-frail older adults [112 control, 44 nutrition (Nu), and 22 in the nutrition with exercise (Nu+Ex) group] comparing the effect of Nu+Ex and Nu on physical function, body composition, and inflammation. At 0, 3, and 6 months, questionnaires on demographics, depression, perceived health, and cognition were administered. Physical function assessment (short physical performance battery [SPPB] test, gait speed, handgrip strength, 5× sit-to-stand [STS]) was conducted, and body composition analysis was performed using a bioelectrical impedance analysis machine. IL-6 and TNF-α were measured at 0 and 3 months.
Results
At 3 months, there were significant improvements in gait speed, 5× STS, SPPB scores, depression, perceived health, fat-free mass, and appendicular skeletal muscle mass indices in the Nu+Ex group. Both Nu+Ex and Nu groups had improvements in body cell mass and reductions in IL-6 and TNF-α. The improvements were not sustained after 6 months.
Conclusion
Our study results need to be validated in future longitudinal randomized studies with a larger sample size focusing on populations at risk.
... An attenuated stimulation of MPS by aging is commonly observed following RE (Drummond et al., 2008;Kumar et al., 2009;Fry et al., 2011). This corroborates with an impaired activation of AKT/mTOR pathway and ERK1/2 (Drummond et al., 2008;Kumar et al., 2009;Fry et al., 2011;Rivas et al., 2012;Stec et al., 2015;Francaux et al., 2016), although one study did not confirm this result (Lees et al., 2020). AMPK phosphorylation was also higher in muscles from old compared with young participants at 1 and 3 h following RE (Drummond et al., 2008), which was not confirmed in another study~30 min after RE (Francaux et al., 2016). ...
Age-related loss of skeletal muscle mass leads to a reduction of strength. It is likely due to an inadequate stimulation of muscle protein synthesis (MPS) in response to anabolic stimuli, such as mechanical load. Ribosome biogenesis is a major determinant of translational capacity and is essential for the control of muscle mass. This mini-review aims to put forth the hypothesis that ribosome biogenesis is impaired by aging in response to mechanical load, which could contribute to the age-related anabolic resistance and progressive muscle atrophy. Recent animal studies indicate that aging impedes muscle hypertrophic response to mechanical overload. This is associated with an impaired transcription of ribosomal DNA (rDNA) by RNA polymerase I (Pol I), a limited increase in total RNA concentration, a blunted activation of AKT/mTOR pathway, and an increased phosphorylation of AMPK. In contrast, an age-mediated impairment of ribosome biogenesis is unlikely in response to electrical stimulations. In human, the hypertrophic response to resistance exercise training is diminished with age. This is accompanied by a deficit in long-term MPS and an absence of increased total RNA concentration. The results addressing the acute response to resistance exercise suggest an impaired Pol I-mediated rDNA transcription and attenuated activation/expression of several upstream regulators of ribosome biogenesis in muscles from aged individuals. Altogether, emerging evidence indicates that impaired ribosome biogenesis could partly explain age-related anabolic resistance to mechanical load, which may ultimately contribute to progressive muscle atrophy. Future research should develop more advanced molecular tools to provide in-depth analysis of muscle ribosome biogenesis.
... By contrast, despite a blunted iMyoPS response to EB-RET in OM, we report no differences in the expression of key AA transporters/sensors, LAT-1, SNAT-2, or Sestrin-2 with age or 1 h after EB-RET and whey protein ingestion, similar to recent work from others in YM after combined RET and EAA ingestion (30). Although Sestrin-2 has been reported to be a key leucine sensor in vitro, there is conflicting evidence around the response of Sestrin-2 to aging, acute RET, and protein feeding (31). Our data add to the conflicting evidence of AA transporters/sensors and their putative role in exercise and feeding-induced muscle anabolism. ...
Purpose:
Resistance exercise training (RET) attenuates age-related muscle and strength loss ('sarcopenia'). However, compared with machine-based RET, the efficacy of cost-effective, accessible elastic band RET (EB-RET) for muscle adaptive remodelling lacks supporting mechanistic evidence.
Methods:
8 young (YM; 24 ± 4 yrs) and 8 older (OM; 68 ± 6 yrs) untrained males consumed an oral stable isotope tracer (D2O) combined with serial vastus lateralis muscle biopsies to measure integrated myofibrillar protein synthesis (iMyoPS) and regulatory signalling over ~48 hrs prior to (habitual) and following an acute bout of EB-RET (6x12 repetitions at ~70% of one-repetition maximum). iMyoPS was determined via gas chromatography-pyrolysis-isotope ratio mass spectroscopy and regulatory signalling expression by immunoblot.
Results:
Habitual iMyoPS did not differ between YM and OM (1.62 ± 0.21 vs 1.43 ± 0.47%·day -1, respectively; P = 0.128). There was a significant increase in iMyoPS after EB-RET in YM (2.23 ± 0.69%day -1; P = 0.02), but not OM (1.75 ± 0.54%day -1; P = 0.30). EB-RET increased the phosphorylation of key anabolic signalling proteins similarly in YM and OM at 1 h post-exercise, including p-IRS-1 Ser636/639, p-Akt Ser473, p-4EBP-1 Thr37/46, p-P70S6K Thr389 and p-RPS6 Ser240/244, whereas p-TSC2 Thr1462 and p-mTOR Ser2448 increased only in YM (all P < 0.05). There were no differences in the expression of amino acid transporters/sensors or proteolytic markers following EB-RET.
Conclusions:
iMyoPS was elevated following EB-RET in YM but not OM. However, the increase in acute anabolic signalling with EB-RET was largely similar between groups. In conclusion, the capacity for EB-RET to stimulate iMyoPS may be impaired in older age. Further work may be necessary to optimise prescriptive programming in YM and OM.
... Lees MJ et al. [130] The ingestion of a novel, gel-based, leucine-enriched EAA supplement results in substantial aminoacidemia and anabolic signaling in younger and older individuals. This formulation can augment dietary protein consumption, intracellular anabolic signaling, and aminoacidemia in older adults without deleterious effects on appetite and subsequent energy intake Provision of ample dietary EAA and leucine are necessary to support a skeletal muscle anabolic response in older adults. ...
Frailty is the major expression of accelerated aging and describes a decreased resistance to stressors, and consequently an increased vulnerability to additional diseases in elderly people. The vascular aging related to frail phenotype reflects the high susceptibility for cardiovascular diseases and negative postoperative outcomes after cardiac surgery. Sarcopenia can be considered a biological substrate of physical frailty. Malnutrition and physical inactivity play a key role in the pathogenesis of sarcopenia. We searched on Medline (PubMed) and Scopus for relevant literature published over the last 10 years and analyzed the strong correlation between frailty, sarcopenia and cardiovascular diseases in elderly patient. In our opinion, a right food intake and moderate intensity resistance exercise are mandatory in order to better prepare patients undergoing cardiac operation.
The primary aim of this narrative review is to evaluate the efficacy of essential amino acid (EAA) supplementation as a strategy to increase dietary protein intake and improve muscle mass, strength and function in older adults. A sufficient daily protein intake is widely recognised to be fundamental for the successful management of sarcopenia in older undernourished adults. In practice, optimising protein intakes in older adults is complex, requiring consideration of the dose and amino acid composition (i.e. a complete EAA profile and abundant leucine content) of ingested protein on a per meal basis, alongside the age-related decline in appetite and the satiating properties of protein. Recent studies in older adults demonstrate that EAA-based supplements are non-satiating and can be administered alongside food to enhance the anabolic properties of a meal containing a suboptimal dose of protein; an effect magnified when combined with resistance exercise training. These findings support the notion that EAA supplementation could serve as an effective strategy to improve musculoskeletal health in older adults suffering from non-communicable diseases such as sarcopenia. Compliance is critical for the long-term success of complex interventions. Hence, aspects of palatability and desire to eat are important considerations regarding EAA supplementation. In conclusion, EAA-based supplements enriched with L-Leucine offer an alternative strategy to whole protein sources to assist older adults in meeting protein recommendations. In practice, EAA supplements could be administered alongside meals of suboptimal protein content, or alternatively between meals on occasions when older adults achieve their per meal protein intake recommendations.
