Age-related skeletal muscle loss and function, known as sarcopenia, can lead to frailty and loss of mobility among older adults. Sarcopenia increases the risk of falls and often results in loss of independent living. Healthy diets and physical activity are well known strategies that can help to maintain muscle strength and function. However, metabolic disturbances associated with loss of skeletal muscle mass are not as well understood. For example, the mechanisms by which vitamin C can affect skeletal muscle physiology during aging have not been extensively studied.
Given the lack of research investigating the relevance of vitamin C and skeletal muscle physiology in older populations, Ailsa Welch (University of East Anglia) and colleagues investigated associations between dietary and plasma vitamin C with indirect measures of skeletal muscle mass in a population of 13,000 free-living middle- and older-aged individuals. Fat-free mass was used as a proxy for skeletal muscle mass and estimated using bioelectric impedance analysis. Dietary vitamin C intakes were calculated from 7-day food diary data, and vitamin C was measured in the blood plasma.
Study results published in The Journal of Nutrition showed positive trends between dietary vitamin C and fat-free mass measures for both sexes. Fat-free measures, expressed as a percentage of total mass or standardized by body mass index (BMI), were higher in participants with sufficient as opposed to insufficient plasma vitamin C by 1.6% and 2.0% in men, and 3.4% and 3.9% in women. These findings of positive associations of both dietary and circulating vitamin C with measures of skeletal muscle mass in middle- and older-aged men and women suggest that dietary vitamin C intake may be useful for reducing age-related muscle loss. Ensuring sufficient dietary vitamin C intake by promoting a diet rich in fruits and vegetables may help to reduce age-related loss of skeletal muscle and thus have a wide-reaching public health benefit.
References Lewis LN, Hayhoe RPG, Mulligan AA, Luben RN, Khaw K, Welch AA. Lower Dietary and Circulating Vitamin C in Middle- and Older-Aged Men and Women Are Associated with Lower Estimated Skeletal Muscle Mass. The Journal of Nutrition, Volume 150, Issue 10, October 2020, Pages 2789–2798, https://doi.org/10.1093/jn/nxaa221.