Loss of muscle mass as you age can lead to frailty and reduced quality of life, so building muscle and maintaining it as you get older is a good idea - and vitamin D could help. Recent research from the University of East Anglia shows that older people who get plenty of vit C - commonly found in citrus fruits, berries and vegetables - have the best skeletal muscle mass.1 That’s because it helps to defend our cells against potentially harmful free radicals, preventing age-related muscle loss.