12 January - 20 June 2016

Fish oil supplements improves muscle function in older women but not men

Loss of skeletal muscle is often a common experience of older adults, however the mechanism involved in this loss remains to be fully established. Previous studies have found that n-3 polyunsaturated fatty acids (PUFA’s) may increase muscles mass and function although these studies involved women and not men. A study published in the American Journal of Clinical Nutrition by the Universities of Glasgow and Aberdeen has investigated the effect of long chain n-3 PUFA supplementation on resistance exercise training-induced increased muscle mass and function, and whether these effects differ between men and women.

Loss of skeletal muscle is often a common experience of older adults, however the mechanism involved in this loss remains to be fully established.  Previous studies have found that n-3 polyunsaturated fatty acids (PUFA’s) may increase muscles mass and function although these studies involved women and not men. A study published in the American Journal of Clinical Nutrition by the Universities of Glasgow and Aberdeen has investigated the effect of long chain n-3 PUFA supplementation on resistance exercise training-induced increased muscle mass and function, and whether these effects differ between men and women. 

In this random, double blinded study, fifty participants consumed either 3 long chain n-3 PUFA capsules (3 x 1 g capsules providing 2.1 g EPA/day and 0.6 g DHA/day) or 3 placebo capsules for 18 weeks. During intervention the participants were instructed to maintain their usual diet and physical activity and record any fish intake. Participants performed instructor led resistance exercise twice weekly during the 18 weeks.  At baseline and at week 18, body mass, resting heart rate and blood pressure were measured as well as a short performance physical battery test, consisting of balance, walking speed and timed chair-stand tests.  Blood samples were also collected and an MRI scan was performed. 

Da Boit et al. found that for all groups, as expected, the resistance exercise training increased the participants muscle size, function and quality.  However in men, who took the fish oil supplement over the 18 week intervention period, they observed no extra gains in muscle function or size. The women however who consumed the n-3 PUFA capsules, were found to have increased muscle function, but not size, compared to those in the placebo group. Exercise combined with the n-3 PUFA capsules were found to increase the women’s muscle strength by 34% compared to 16% in the placebo group.

In a press release Dr Stuart Gray from the University of Glasgow’s Institute of Cardiovascular and Medical Sciences (formerly of the University of Aberdeen, where much of the study was completed) said: “These findings provide important information for nutritional guidelines in older people where policy makers may want to consider recommendations for fish oil supplements to be consumed by older women.  Why men do not see the same benefit as women is important to understand and the underlying mechanisms need to be studied.”

The study states “it may be possible that long chain n-3 PUFAs only have effect in women because there is a greater capacity for improvement; i.e. their normal response is suboptimal compared with men.  This would make women more amenable to the effects of long-chain n-3 PUFAs.” However they note that these mechanisms are speculative and further research is needed.

RSSL has expertise in all aspects of fat analysis and fatty acid profiling. For more information please contact Customer Services on +44 (0) 118 918 4076 or email enquiries@rssl.com

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