The effect of dietary n-3 long-chain polyunsaturated fatty acids on femur mineral density and biomarkers of bone metabolism in healthy, diabetic and dietary-restricted growing rats

Introduction: Dietary fish oil promotes bone formation in healthy states, but its effect during insulin deficiency or nutrient restriction is unclear. Methods: Eighty weanling male rats were randomized to receive an injection of streptozotocin to induce insulin deficiency (diabetes) or saline (control) and a diet containing soy oil or corn + fish oil for 35 days. Half of the saline-injected rats were randomized to 20% dietary restriction. Measurements were growth, biomarkers of bone metabolism and femur bone mass. Results: Density of femur was elevated in the corn + fish group and reduced in the diabetes group. Plasma osteocalcin and bone prostaglandin E-2 (PGE(2)) were reduced by the corn + fish diet. N-telopeptide, IGF-1, bone PGE(2) and urinary Ca were highest and calcitriol lowest in the diabetes group. Conclusions: These data suggest that the benefit of a diet high in n-3 long-chain polyunsaturated fatty acid is most advantageous to long bone density in healthy states. (C) 2004 Elsevier Ltd. All rights reserved.