However, data are from the Age, Gene/Environment Susceptibility–Reykjavik Study indicated no relationship between muscle parameters and fish oil consumption during middle and old age. An association was observed for fish oil consumption during youth and grip strength, but this never reached statistical significance.
“This is one of the first population-based studies, to our knowledge, examining the association between circulating concentrations of fatty acids and comprehensive cross-sectional and longitudinal muscle parameters that are important indicators of physical function in older adults,” wrote the authors in the Journal of Nutrition.
“Total PUFAs were positively associated with cross-sectional muscle size and knee extension strength, but there were inconsistent associations with individual fatty acids, including the n–3 PUFAs, which are widely hypothesized to play a role in muscle mass and/or strength.”
The study authors were affiliated with the US National Institute on Aging, the VU University Medical Center (The Netherlands), Fred Hutchinson Cancer Research Center (USA), the Icelandic Heart Association Research Institute, and the University of Iceland.
Cautious optimism
Commenting independently on the study’s findings, Harry Rice, PhD, VP of regulatory & scientific affairs for the Global Organization for EPA and DHA Omega-3s (GOED), told us: “Sarcopenia (loss of muscle mass, strength and function) is an inevitable process of aging, but its attenuation could have significant quality of life, not to mention economic, benefits.
“While the present research suggests only some benefits associated with higher EPA+DHA status, the interpretation of the results should be done with caution because the reference group included individuals whose fatty acid profile was relatively high for EPA+DHA. It would be interesting to conduct similar research in a population whose fatty acid profile was lower. There is a body of evidence, albeit limited, suggesting that the results would demonstrate a more significant benefit.
“Given the cardioprotective benefits associated with EPA & DHA, not to mention a long history of safe use and the potential to slow down sarcopenia, it makes good sense to increase one's omega-3 intake through diet and supplementation.”
Study details
Led by Ilse Reinders from the National Institute on Aging, the researchers analyzed data from 836 people aged between 66 and 96 who were followed for an average of 5.2 years. Results of the study indicated higher levels of total PUFAs were associated with bigger muscles and greater knee extension strength.
When the researchers considered individual fatty acids, they found that higher levels of arachidonic acid were associated with smaller muscles, whereas higher alpha-linolenic acid levels were linked to greater knee extension strength.
Higher linoleic acid levels were associated with lower levels of intermuscular fat tissue, they added, whereas EPA was associated with higher levels of intermuscular fat tissue.
Previous studies have reported that fish oil supplements may stimulate muscle protein synthesis in older adults, but this was not seen in this study, which may be due to the higher baseline omega-3 levels observed in the Icelandic population, said the researchers.
“Future studies should investigate whether changes in PUFA profiles are associated with muscle parameters,” they wrote. “In addition, because this is the first longitudinal population-based study, to our knowledge, our results need to be confirmed by studies investigating the association between PUFAs and changes in muscle parameters in different study populations.”
Omega-3s and exercise economy
There is a small but growing body of science supporting the potential role of omega-3s for exercise benefits, including a recent study from Japan that found that daily supplements of an EPA-rich fish oil may boost exercise economy, a predictor of endurance exercise performance.
Data published in Bioscience, Biotechnology, and Biochemistry indicated that a daily fish oil dose of 3.6 grams for eight weeks was associated with increases in EPA and DHA levels in red blood cells (erythrocytes) and decreases in oxygen uptake (VO2) during steady-state submaximal exercise.
Source: Journal of Nutrition
Published online ahead of print, doi:10.3945/jn.114.200337
“Plasma Phospholipid PUFAs Are Associated with Greater Muscle and Knee Extension Strength but Not with Changes in Muscle Parameters in Older Adults”
Authors: I. Reinders, X. Song, M. Visser, et al.