The impact of supplemental n-3 long chain polyunsaturated fatty acids and dietary antioxidants on physical performance in postmenopausal women.

OBJECTIVES: Identify relationships and evaluate effects of long chain polyunsaturated fatty acids (LCPUFA) on frailty and physical performance.

DESIGN: Randomized, double blind pilot study.

SETTING: University General Clinical Research Center.

PARTICIPANTS: 126 postmenopausal women.

INTERVENTION: 2 fish oil (1.2g eicosapentaenoic acid [EPA] and docosahexaenoic acid [DHA]) or 2 placebo (olive oil) capsules per day for 6 months. All participants received calcium and vitamin D supplements.

MEASUREMENTS: Fatty acid levels, frailty assessment, hand grip strength, 8 foot walk, body composition, medical history and co-morbidities, nutrient intake, and inflammatory biomarkers taken at baseline and 6 months.

RESULTS: At baseline, those with greater red blood cell (RBC) DHA and DHA/arachidonic acid (AA) presented with less frailty (r = -0.242, p=0.007 and r = -0.254, p=0.004, respectively). Fish oil supplementation resulted in higher RBC DHA and lower AA compared to baseline and placebo (p<0.001) and an improvement in walking speed compared to placebo (3.0±16 vs. -3.5±14, p=0.038). A linear regression model included age, antioxidant intake (selenium and vitamin C), osteoarthritis, frailty phenotype, and tumor necrosis factor alpha (TNFα). The model explained 13.6% of the variance in the change in walking speed. Change in DHA/AA (p=0.01) and TNFα (p=0.039), and selenium intake (p=0.031) had the greatest contribution to change in walking speed.

CONCLUSION: Physical performance, measured by change in walking speed, was significantly affected by fish oil supplementation. Dietary intake of antioxidants (selenium and vitamin C) and changes in TNFα also contributed to change in walking speed suggesting LCPUFA may interact with antioxidants and inflammatory response to impact physical performance.