Fish oil enhances muscle strength and functional abilities after resistance training in elderly women: A preliminary study

Abstract

Anabolic resistance of muscle protein synthesis to resistance training(1) and nutrition(2) has been proposed as a potential cause of sarcopenia. Fish oil supplementation increases muscle protein synthesis in response to insulin and amino acids in older adults(3) and may improve adaptations to resistance training in older women. However, this needs to be confirmed by results obtained from placebo controlled trials(4). The aim of the current study was to determine whether fish oil can enhance adaptations in skeletal muscle function after resistance training in elderly women. A double-blind randomized placebo-controlled study design was used in this pilot study. Thirteen participants were randomly assigned to receive either 4 g fish oil (containing 1.7 g EPA and 0.4 g DHA) or 4 g control oil (olive oil) daily for 12 weeks. Participants also carried out resistance training twice a week for this period. Plasma profiles (i.e., phospholipid fatty acid composition, glucose, triglycerides, insulin and IL-6), a short performance battery test(5), and isometric and isokinetic quadriceps muscle strength were determined pre- and post-intervention. Results are presented as means (SD). (Table Presented) All baseline measures were similar between groups. Plasma EPA and DPA concentrations significantly increased in the fish oil group, compared with the control (P = 0.01 and P = 0.03 respectively), while insulin resistance, as measured by HOMA-IR, significantly decreased (P = 0.03). Post-intervention, the fish oil group showed a greater increase in isometric muscle strength (31.8 ± 8.7 vs. 15 ± 9.6 N/m in fish oil and control groups, respectively; P = 0.001) and a gait speed (0.24 ± 0.12 vs. 0.09 ± 0.11 m/s in fish oil and control group, respectively P = 0.03) compared with the control group (Table 1). However, post-intervention, there were no differences in isokinetic muscle strength, balance, chair rise time, or plasma IL-6 and triglyceride concentrations. We have demonstrated that 12 weeks supplementation with 4 g fish oil daily enhance the adaptive responses to resistance exercise and reduce markers of insulin resistance in elderly women, suggesting that fish oil may be beneficial to attenuate age-related loss of muscle mass.