Animal and human studies indicate that omega (n)-3 polyunsaturated fatty acids (PUFA) can influence bone health. We conducted a randomized, double-blind, placebo-controlled trial of the effects of n-3 long chain (LC) PUFA supplementation (N-3 LCPUFA) on red blood cell (RBC) fatty acid levels and bone turnover markers in older postmenopausal women. One hundred and twenty-six postmenopausal women (mean age 75±7 years) were treated with n-3 LCPUFA (1.2 g eicosapentaenoic acid [EPA]/docosahexaenoic acid [DHA]/day, n=85) or placebo (olive oil, n=41) for 6 months. All women received 315 mg calcium citrate and 1000 IU cholecalciferol. RBC DHA (weight %) increased in the n-3 LCPUFA group, compared to no change in the placebo group (P<0.001). The ratio of DHA+EPA:arachidonic acid (AA) increased by 42 % in the n-3 LCPUFA group and by 5% in the placebo group (P<0.001). Bone-specific alkaline phosphatase and osteocalcin decreased in the n-3 LCPUFA group (P<0.05) with no between-group difference. Short-term n-3 LCPUFA supplementation increased RBC concentrations of DHA and n-3:n-6 ratios. Bone turnover decreased with n-3 LCPUF, but not statistically compared to placebo. The results point to the need for investigations with greater dosages of n-3 LCPUFA for a longer duration to understand the contribution to bone metabolism in postmenopausal women.
Keywords: bone turnover; fish oil; low bone mass; omega-3 fatty acids; osteoporosis; postmenopausal women.