Research shows that weight loss in the elderly is associated with an increased risk of all cause mortality, especially when that weight loss occurs from skeletal muscle. Resistance training is one strategy that is effective at preventing loss of lean mass and has been shown to be of benefit to elderly individuals. Because resistance training is a form of stress and causes metabolic challenges, dietary changes are required in order to optimise skeletal muscle hypertrophy and muscular strength gains. One component of the diet that has been extensively researched in this regard is dietary protein. However, intakes of essential nutrients may be equally as important because often deficiencies exist within the elderly, due to a combination of decrease absorption and poor diet. Of the nutrients likely to be deficient from the diets of the elderly, the n-3 fatty acids have been identified.
The fatty acids eicosapentanoic acid (EPA, C20:5 (n-3)) and docosahexanoic acid (DHA, C22:6 (n-3)) in fish oils may improve insulin resistance and plasma membrane function. Optimising intakes of these fatty acids through fish oil supplementation may therefore be beneficial in weight training. Researchers have investigated the effects of fish oil supplementation on the benefits of resistance training in 45 elderly women (mean age 64 years). Subjects were randomly assigned to perform resistance training for 90 days, with or without fish oil (2g/d). A third group performed resistance training for 90 days but received supplementation with fish oils for 60 days preceding, as well as during, the training period. The results showed that resistance training caused significant increases in peak torque and rate of torque development in all groups compared to baseline. However, the effects were significantly greater in the fish oil groups compared to the control group.
These data suggests that fish oil supplementation is beneficial at increasing muscular function in elderly subjects undergoing resistance training. This may be because the diets of the women were deficient in n-3 fatty acids and the supplementation restored a sub-clinical deficiency. Plasma levels of EPA and DHA increased significantly in all subjects receiving the fish oil supplements, but not the control group. In humans, conversion of DHA to EPA is possible via an elongase enzyme, and the subsequent EPA an then be converted to eicosanoids which may have beneficial effects on plasma membrane function. However, DHA is specifically taken up my the neuromuscular system, and can be incorporated in plasma membranes where it is converted to docosanoids such as neuroprostanes, maresins, neuroprotectin D1, D series resolvins, docosatrienes and other 22-carbon derivatives that may have specific neuronal and muscular effects.
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