A new National Institutes of Health-funded study holds out the first glimmer of hope that high doses of omega-3 fatty acid supplements might counter the degenerative muscle loss that leads to frailty in the elderly. The inability of aging muscle to maintain the production of muscle protein is a key factor in sarcopenia, a condition first identified by Tufts scientists, which is characterized by a loss of lean muscle mass, strength and function.
In the new study, Bettina Mittendorfer, PhD, of Washington University in St. Louis, and colleagues randomly assigned 16 healthy adults, average age 71, to either a corn-oil placebo or almost four grams daily of the omega-3s found in fish oil. Thats considerably more omega-3s than found in typical fish-oil supplements. The researchers used Lovaza, a prescription-strength omega-3 approved by the FDA for treating high triglycerides. Each dose contains 1.86 grams of EPA and 1.5 grams of DHA, the two primary omega-3 fatty acids found in fish oil.
We chose this (high) dose because it is the dose approved by the Food and Drug Administration for lowering plasma triglyceride concentrations in hypertriglyceridemic subjects and has therefore previously been shown to be physiologically relevant in human subjects, the researchers explained.
After eight weeks, those receiving the omega-3s saw an increase in the synthesis of muscle protein in response to nutritional stimuli such as amino acids and insulin. The omega-3 group also experienced an improvement in a signaling pathway in the body believed to be key to muscle-cell growth.
The mechanism by which omega-3s might boost muscle synthesis isnt clear, Mittendorfer and colleagues noted. But they concluded in the American Journal of Clinical Nutrition that their study provides compelling evidence of an interaction of omega-3 fatty acids and protein metabolism in human muscle and suggests that dietary omega-3 fatty acid supplementation could potentially provide a safe, simple and low-cost intervention to combat sarcopenia.
The study, according to Mittendorfer and colleagues, is the first to report potential benefits of omega-3 fatty acids against sarcopenia. The investigators plan follow-up trials with more subjects to test functional outcomes.
Roger A. Fielding, PhD, director of Tufts HNRCA Nutrition, Exercise Physiology and Sarcopenia Laboratory, comments, Its possible the omega-3 fatty acids may alter how your muscles respond to the hormone insulin and cause more efficient uptake of amino acids and turn on protein synthesis. However, we still dont know if these acute effects of high-dose fish oils will safely prevent muscle loss or sarcopenia over a lifetime.
TO LEARN MORE: American Journal of Clinical Nutrition, online ahead of print, dx.doi.org/10.3945/ajcn.110.005611. Your Muscles: Secrets of Aging Gracefully-Inside Tufts HNRCA Laboratory of Nutrition, Exercise, Physiology and Sarcopenia, May 2011 Healthletter Special Report.