A Whole-Grain Diet Increases Whole-Body Protein Balance Compared with a Macronutrient-Matched Refined-Grain Diet

Background: There are limited data from randomized control trials to support or refute the contention that whole-grains can enhance protein metabolism in humans. Objectives: To examine: 7) the clinical effects of a whole-grain diet on whole-body protein turnover; 2) the cellular effects of whole-gra...

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Published in:Current developments in nutrition 2021-11, Vol.5 (11), p.1
Main Authors: Mey, Jacob T, Godin, Jean-Philippe, Scelsi, Amanda R, Kullman, Emily L, Malin, Steven K, Yang, Shengping, Floyd, Z. Elizabeth, Poulev, Alexander, Fielding, Roger A, Ross, Alastair B, Kirwan, John P
Format: Article
Language:English
Subjects:
Aged
Food and nutrition
Grain
Health aspects
Muscles
Nutritional aspects
Physiological aspects
Protein metabolism
Proteins in human nutrition
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Summary:Background: There are limited data from randomized control trials to support or refute the contention that whole-grains can enhance protein metabolism in humans. Objectives: To examine: 7) the clinical effects of a whole-grain diet on whole-body protein turnover; 2) the cellular effects of whole-grains on protein synthesis in skeletal muscle cells; and 3) the population effects of whole-grain intake on age-related muscle loss. Methods: Adults with overweight/obesity (n = 14; age = 40 [+ or -] 7 y; BMI = 33 [+ or -] 5 kg/[m.sup.2]) were recruited into a crossover, randomized controlled trial (NCT01411 540) in which isocaloric, macronutrient-matched whole-grain and refined-grain diets were fully provisioned for two 8-wk periods. Diets differed only in the presence of whole-grains (50 g/1000 kcal). Whole-body protein kinetics were assessed at baseline and after each diet in the fasted-state ([.sup.13]C-leucine) and integrated over 24 h ([.sup.15]N-glycine). In vitro studies using C2C1 2 cells assessed global protein synthesis by surface sensing of translation and anabolic signaling by Western blot. Complementary epidemiological assessments using the NHANES database assessed the effect of whole-grain intake on muscle function assessed by gait speed in older adults (n = 2783). Results: Integrated 24-h net protein balance was 3-fold higher on a whole-grain diet compared with a refined-grain diet (P = 0.04). A whole-grain wheat extract increased submaximal rates of global protein synthesis (27%, P < 0.05) in vitro. In a large sample of older adults, whole-grain intake was associated with greater muscle function (OR = 0.92; 95% CI: 0.86, 0.98). Conclusions: Consuming 50 g/1000 kcal whole-grains per day promotes greater protein turnover and enhances net protein balance in adults. Whole-grains impact skeletal muscle at the cellular level, and are associated with greater muscle function in older adults. Collectively, these data point to a new mechanism whereby whole-grain consumption favorably enhances protein turnover and improves health outcomes. This clinical trial is registered on clinicaltrials.gov (identifier: NCT01411540). Curr Dev Nutr 2021 ;5:nzab121. Keywords: grain, polyphenol, phytonutrient, phytochemical, botanical, sarcopenia, muscle function, processed food, nitrogen, walking speed
ISSN:2475-2991
2475-2991
DOI:10.1093/cdn/nzab121