Daily leucine intake is positively associated with lower limb skeletal muscle mass and strength in the elderly.

Lixandr�o, Manoel E.; Longobardi, Igor; Leit�o, Alice E.; Morais, Jo�o V.M.; Swinton, Paul A.; Aihara, Andr� Y.; Goes, Paola C.K.; Ugrinowitsch, Carlos; Candow, Darren G.; Gualano, Bruno; Roschel, Hamilton

Abstract

Higher daily protein intake, with an emphasis on leucine content, is thought to mitigate age-related anabolic resistance, potentially counteracting age-related morphological and functional declines. The present study investigated potential associations between total daily leucine intake and dependent variables, including quadriceps muscle cross-sectional area (CSA) and maximum dynamic muscle strength (1-RM) in a cohort of healthy free-living older individuals of both sexes (n = 67; 34/33 men/women). Participants performed three 24-hour dietary recalls and underwent a magnetic resonance imaging exam followed by 1-RM tests. Our results demonstrate moderate associations between total daily leucine and both quadriceps CSA (r = 0.42; p = 0.004) and 1-RM (r = 0.45; p = 0.001). Furthermore, our exploratory biphasic linear regression analyses, adjusted for sex, age, and protein intake relative to body weight, revealed a plateau for daily leucine intake and muscle mass and muscle strength (around 7.6–8.0 g/day−1) in older adults. In conclusion, we demonstrated that total daily leucine intake is associated with muscle mass and strength in healthy older individuals and this association remains after controlling for multiple factors, including overall protein intake. Furthermore, our breakpoint analysis revealed non-linearities and a potential threshold for habitual leucine intake, which may help guide future research on the effects of chronic leucine intake in age-related muscle loss.

Citation

LIXANDRÃO, M.E., LONGOBARDI, I., LEITÃO, A.E., MORAIS, J.V.M., SWINTON, P.A., AIHARA, A.Y., GOES, P.C.K., UGRINOWITSCH, C., CANDOW, D.G., GUALANO, B. and ROSCHEL, H. 2021. Daily leucine intake is positively associated with lower limb skeletal muscle mass and strength in the elderly. Nutrients [online], 13(10), article number 3536. Available from: https://doi.org/10.3390/nu13103536

• Journal Article Type: Article
• Acceptance Date: Oct 6, 2021
• Online Publication Date: Oct 9, 2021
• Publication Date: Oct 31, 2021
• Deposit Date: Oct 20, 2021
• Publicly Available Date: Oct 20, 2021
• Journal: Nutrients
• Electronic ISSN: 2072-6643
• Publisher: MDPI
• Peer Reviewed: Peer Reviewed
• Volume: 13
• Issue: 10
• Article Number: 3536
• DOI: https://doi.org/10.3390/nu13103536
• Keywords: Protein intake; Ageing; Muscle function; Essential amino acids; Older people
• Public URL: https://rgu-repository.worktribe.com/output/1500075