Physiological processes of aging: are there special nutritional requirements for elderly people? Do McCay's findings apply to humans?

Abstract

Aging is characterized by shrinkage of muscle fibers and loss of protein from them. Bone is also lost, and matrix and mineral are lost together. The predominance of breakdown over synthesis is probably the fundamental cause of both muscle and bone loss. Little can be done to prevent this by dietary means, but physical activity is of vital importance in helping to maintain the integrity of both muscle and bone. McCay's finding that rats underfed from weaning lived longer than those that had adequate food has been confirmed by others, but this is only true if the rats remain free of infections and other hazards, particularly during growth. The mechanisms by which underfeeding delays the aging process in rats may apply to the human body but, if so, this is completely offset by other considerations. For their present and future well-being, children should be fed in the best possible way.