Protective effects of fish intake and interactive effects of long-chain polyunsaturated fatty acid intakes on hip bone mineral density in older adults: the Framingham Osteoporosis Study.

BACKGROUND

Polyunsaturated fatty acids and fish may influence bone health.

OBJECTIVE

We aimed to examine associations between dietary polyunsaturated fatty acid and fish intakes and hip bone mineral density (BMD) at baseline (1988-1989; n = 854) and changes 4 y later in adults (n = 623) with a mean age of 75 y in the Framingham Osteoporosis Study.

DESIGN

BMD measures were regressed on energy-adjusted quartiles of fatty acid intakes [n-3 (omega-3): α-linolenic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and EPA+ DHA; n-6 (omega-6): linoleic acid (LA) and arachidonic acid (AA); and n-6:n-3 ratio] and on categorized fish intakes, with adjustment for covariates. Effect modification by EPA+DHA intake was tested for n-6 exposures.

RESULTS

High intakes (≥3 servings/wk) of fish relative to lower intakes were associated with maintenance of femoral neck BMD (FN-BMD) in men (dark fish + tuna, dark fish, and tuna) and in women (dark fish) (P < 0.05). Significant interactions between AA and EPA+DHA intakes were observed cross-sectionally in women and longitudinally in men. In women with EPA+DHA intakes at or above the median, those with the highest AA intakes had a higher mean baseline FN-BMD than did those with the lowest intakes (quartile 4 compared with quartile 1: P = 0.03, P for trend = 0.02). In men with the lowest EPA+DHA intakes (quartile 1), those with the highest intakes of AA (quartile 4) lost more FN-BMD than did men with the lowest intakes of AA (quartile 1; P = 0.04). LA intake tended to be associated with FN-BMD loss in women (P for trend < 0.06).

CONCLUSIONS

Fish consumption may protect against bone loss. The protective effects of a high AA intake may be dependent on the amount of EPA+DHA intake.