Lifelong intake of flaxseed or menhaden oil to provide varying n-6 to n-3 PUFA ratios modulate bone microarchitecture during growth, but not after OVX in Sprague-Dawley rats

Scope: Skeletal health is a lifelong process impacted by environmental factors, including nutrient intake. The n-3 source and PUFA ratio affect bone health in growing rats, or following ovariectomy (OVX), but no study has investigated the longitudinal effect of PUFAsupplementation throughout these periods of bone development. Methods and results: One-month-old, Sprague-Dawley rats (n = 98) were randomized to receive one of four diets from 1 through 6months of age. Diets weremodified from AIN-93G to contain a varying amount and source of n-3 (flaxseed versusmenhaden oil) to provide an n-6 to n3 ratio of 10:1 or 5:1. At 3 (prior to SHAMor OVX) and 6 months of age, bone microarchitecture of the tibia was quantified using in vivo micro-computed tomography (SkyScan 1176, Bruker microCT). Providing 5:1 (flaxseed) resulted in lower trabecular thickness and medullary area and greater cortical area fraction during growth compared to diets with a 10:1 PUFA ratio, but many of these differences were not apparent following OVX. Conclusion: PUFA-supplementation at levels attainable in human diet modulates some bone structure outcomes during periods of growth, but is not an adequate strategy for the prevention of OVX-induced bone loss in rats