Effect of fish oil supplementation on bone turnover markers in women on aromatase inhibitors: a pilot study

Abstract

Aromatase inhibitors (AI) are adjunctive therapies for estrogen‐receptor positive breast cancer (BC); however, they exacerbate bone loss. We tested the effects of a non‐pharmacological treatment, fish oil, on bone measures in 37 postmenopausal BC survivors on AI. In addition to calcium (1,000 mg/d) and cholecalciferol (800 IU/d), women were randomly assigned to 4 g eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)/d via fish oil or placebo (safflower oil) capsules. Bone mineral density was low in 41% of women; none were osteoporotic. Average age was 61.8±9.7 and BMI 28.0±5.8. There were no between group differences in dietary intake of calories, protein, calcium, vitamin D, n‐3 or n‐6 fatty acids, or other nutrients. Resorption and formation markers (serum C‐terminal telopeptide [sCTX] and procollagen type 1 N‐terminal propeptide [P1NP], respectively) were measured at baseline and 3 months. Baseline sCTX and P1NP were similar between groups. sCTX was reduced by −7.8±20.8% and P1NP by −10.2±16.5% in the EPA+DHA group. The reductions in turnover markers in the EPA+DHA group were not statistically different compared to changes in placebo (sCTX 0.4±20.4; P1NP −3.3±15.9). In this high risk group, nutritional supplementation was not enough to overcome the effects of AI on bone turnover. Project supported by the CT Breast Health Initiative and University of Connecticut Health Center Clinical Research Center.