Review published in Advances in Nutrition finds omega-3 fatty acid supplementation “may lead to very small increases in muscle strength.”

Omega-3 fatty acids are polyunsaturated fats that perform key functions in the body, including supporting cardiovascular, immune, brain, and neuromuscular function.  We humans aren’t able to produce the amount of omega-3 fatty acids our bodies need.  Omega-3 fatty acids therefore are considered essential nutrients, meaning we need to get them from the foods we eat.  In some cases, healthcare providers may recommend omega-3 fatty acid supplementation.

Recently, studies have investigated the effect of omega-3 fatty acid supplementation on muscle mass, strength, and function; however, the results have been inconclusive.  Some studies found omega-3 fatty acid supplementation enhanced muscle mass, strength and function, while others found no effect.  In response, the authors of The Influence of n-3PUFA Supplementation on Muscle Strength, Mass and Function: A Systematic Review and Meta-analysis synthesized and reviewed the current evidence to determine to what degree it suggested an effect of omega-3 fatty acid supplementation on muscle mass, strength, and function among healthy young and older adults.  Their review was published in Advances in Nutrition, the international review journal of the American Society for Nutrition.

To conduct their research, the authors performed a comprehensive search of the scientific literature, eventually leading them to 14 studies that met their criteria.  These 14 studies included a total of 1,443 participants (913 females and 520 males).  Upon reviewing the studies, the authors concluded that, when compared to a placebo, “omega-3 fatty acid supplementation may lead to very small increases in muscle strength but did not impact muscle mass and function in healthy young and older adults.”  The authors believe that “this could be explained, at least in part, by the fact that increases in muscle strength are not necessarily correlated with changes in muscle size, since neural motor control and/or cellular and molecular adaptations of muscle fibers may lead to increases in muscle strength in the absence of significant increases in muscle mass.”

While the authors did find “a positive, albeit very small, effect of omega-3 fatty acid supplementation on muscle strength when compared to placebo,” they did “urge caution in interpreting this result.”  In particular, the authors pointed to differences in individual study design and results, making it difficult to reach conclusions.  Overall, “the effect of omega-3 fatty acid supplementation on strength is compatible with trivially small benefits, and it is unlikely that such small changes would be clinically meaningful or relevant.”

The authors did point to a previous review that found a stronger relationship between omega-3 fatty acid supplementation and increased muscle mass and function among the elderly than their current review; however, they believe the difference might be explained by differences in the study populations.  In this current review, only healthy subjects were analyzed.  In the earlier review, older adults with chronic illness were included in the study population.  The authors believe that omega-3 fatty acid supplementation may have a more pronounced effect on older adults with chronic illness: “previous literature suggests that omega-3 fatty acid supplementation may be more likely to provide an anabolic stimulus in situations whereby muscle protein synthesis is compromised such as…within older adults who have higher degrees of anabolic resistance and in conditions of increased systemic inflammation, such as chronic diseases.”

The authors did acknowledge some limitations of their review, including “high overall risk of bias from the included studies, mostly due to the lack of information about the randomization process and blinding and the lack of plan trial registries.”  To shed further light on this topic, “future studies with rigorous methodology and reporting of data are necessary to expand and confirm these results.”

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