Sarcopenia is a major issue of aging

http://www.ncbi.nlm.nih.gov/m/pubmed/25809808/?i=2&from=protein+and+sarcopenia

CONCLUSIONS: It is concluded that leucine supplementation was found to exert beneficial effects on body weight, body mass index, and lean body mass in older persons in those subjects already prone to sarcopenia, but not muscle strength. However, due to the heterogeneity between the trials included in this systematic review, further studies adopting a homogenous design with respect to participant characteristics duration as well as the kind and amount of daily supplement in use are required.

Cancer patients are disabled by sarcopenia. It seems that EPA can help.
http://www.ncbi.nlm.nih.gov/m/pubmed/25770317/?i=7&from=protein+and+sarcopenia