Defining meal requirements for protein to optimize metabolic roles of amino acids
- PMID: 25926513
- PMCID: PMC5278948
- DOI: 10.3945/ajcn.114.084053
Defining meal requirements for protein to optimize metabolic roles of amino acids
Abstract
Dietary protein provides essential amino acids (EAAs) for the synthesis of new proteins plus an array of other metabolic functions; many of these functions are sensitive to postprandial plasma and intracellular amino acid concentrations. Recent research has focused on amino acids as metabolic signals that influence the rate of protein synthesis, inflammation responses, mitochondrial activity, and satiety, exerting their influence through signaling systems including mammalian/mechanistic target of rapamycin complex 1 (mTORC1), general control nonrepressed 2 (GCN2), glucagon-like peptide 1 (GLP-1), peptide YY (PYY), serotonin, and insulin. These signals represent meal-based responses to dietary protein. The best characterized of these signals is the leucine-induced activation of mTORC1, which leads to the stimulation of skeletal muscle protein synthesis after ingestion of a meal that contains protein. The response of this metabolic pathway to dietary protein (i.e., meal threshold) declines with advancing age or reduced physical activity. Current dietary recommendations for protein are focused on total daily intake of 0.8 g/kg body weight, but new research suggests daily needs for older adults of ≥1.0 g/kg and identifies anabolic and metabolic benefits to consuming at least 20-30 g protein at a given meal. Resistance exercise appears to increase the efficiency of EAA use for muscle anabolism and to lower the meal threshold for stimulation of protein synthesis. Applying this information to a typical 3-meal-a-day dietary plan results in protein intakes that are well within the guidelines of the Dietary Reference Intakes for acceptable macronutrient intakes. The meal threshold concept for dietary protein emphasizes a need for redistribution of dietary protein for optimum metabolic health.
Keywords: leucine; mTOR; muscle protein synthesis; nitrogen balance; satiety.
© 2015 American Society for Nutrition.
Similar articles
-
Impacts of protein quantity and distribution on body composition.Front Nutr. 2024 May 3;11:1388986. doi: 10.3389/fnut.2024.1388986. eCollection 2024. Front Nutr. 2024. PMID: 38765819 Free PMC article. Review.
-
International Society of Sports Nutrition Position Stand: Effects of essential amino acid supplementation on exercise and performance.J Int Soc Sports Nutr. 2023 Dec;20(1):2263409. doi: 10.1080/15502783.2023.2263409. Epub 2023 Oct 6. J Int Soc Sports Nutr. 2023. PMID: 37800468 Free PMC article.
-
Essential amino acid-enriched whey enhances post-exercise whole-body protein balance during energy deficit more than iso-nitrogenous whey or a mixed-macronutrient meal: a randomized, crossover study.J Int Soc Sports Nutr. 2021 Jan 7;18(1):4. doi: 10.1186/s12970-020-00401-5. J Int Soc Sports Nutr. 2021. PMID: 33413462 Free PMC article. Clinical Trial.
-
International Society of Sports Nutrition Position Stand: protein and exercise.J Int Soc Sports Nutr. 2017 Jun 20;14:20. doi: 10.1186/s12970-017-0177-8. eCollection 2017. J Int Soc Sports Nutr. 2017. PMID: 28642676 Free PMC article. Review.
-
Dietary proteins and amino acids in the control of the muscle mass during immobilization and aging: role of the MPS response.Amino Acids. 2017 May;49(5):811-820. doi: 10.1007/s00726-017-2390-9. Epub 2017 Feb 7. Amino Acids. 2017. PMID: 28175999 Review.
Cited by
-
Impacts of protein quantity and distribution on body composition.Front Nutr. 2024 May 3;11:1388986. doi: 10.3389/fnut.2024.1388986. eCollection 2024. Front Nutr. 2024. PMID: 38765819 Free PMC article. Review.
-
Identification of a leucine-mediated threshold effect governing macrophage mTOR signalling and cardiovascular risk.Nat Metab. 2024 Feb;6(2):359-377. doi: 10.1038/s42255-024-00984-2. Epub 2024 Feb 19. Nat Metab. 2024. PMID: 38409323
-
Diabesity and Dietary Interventions: Evaluating the Impact of Mediterranean Diet and Other Types of Diets on Obesity and Type 2 Diabetes Management.Nutrients. 2023 Dec 21;16(1):34. doi: 10.3390/nu16010034. Nutrients. 2023. PMID: 38201865 Free PMC article. Review.
-
Intermittent fasting interventions to leverage metabolic and circadian mechanisms for cancer treatment and supportive care outcomes.J Natl Cancer Inst Monogr. 2023 May 4;2023(61):84-103. doi: 10.1093/jncimonographs/lgad008. J Natl Cancer Inst Monogr. 2023. PMID: 37139971 Free PMC article.
-
The effect of 8-weeks of combined resistance training and chocolate milk consumption on maximal strength, muscle thickness, peak power and lean mass, untrained, university-aged males.Front Physiol. 2023 Mar 15;14:1148494. doi: 10.3389/fphys.2023.1148494. eCollection 2023. Front Physiol. 2023. PMID: 37007992 Free PMC article.
References
-
- Houston DK, Nicklas B, Ding J, Harris T, Tylavsky F, Newman A, Lee J, Sahyoun N, Visser M, Kritchevsky S. Dietary protein intake is associated with lean mass change in older, community-dwelling adults: the Health, Aging, and Body Composition (Health ABC) Study. Am J Clin Nutr 2008;87:150–5. - PubMed
-
- Gaffney-Stomberg E, Insogna K, Rodriguez N, Kerstetter J. Increasing dietary protein requirements in elderly people for optimal muscle and bone health. J Am Geriatr Soc 2009;57:1073–9. - PubMed
-
- Skov AR, Toubro S, Bulow J, Krabbe K, Parving H, Astrup A. Changes in renal function during weight loss induced by high vs low-protein low-fat diets in overweight subjects. Int J Obes Relat Metab Disord 1999;23:1170–7. - PubMed
-
- Layman DK, Evans E, Erickson D, Seyler J, Weber J, Bagshaw D, Griel A, Psota T, Kris-Etherton P. A moderate-protein diet produces sustained weight loss and long-term changes in body composition and blood lipids in obese adults. J Nutr 2009;139:514–21. - PubMed
Grants and funding
LinkOut - more resources
Full Text Sources
Other Literature Sources
Miscellaneous