Female rats consuming an iron and omega-3 fatty acid deficient diet preconception require combined iron and omega-3 fatty acid supplementation for the prevention of bone impairments in offspring

We previously showed in rats that pre- and postnatal deficiencies in iron and omega-3 (n-3) fatty acids can impair bone development, with additive and potentially irreversible effects when combined. This study aimed to investigate, in female rats consuming a combined iron and n-3 fatty acid deficient (ID + n-3 FAD) diet preconception, whether supplementation with iron and docosahexaenoic/eicosapentaenoic acid (DHA/EPA), alone and in combination, can prevent bone impairments in offspring. Using a 2 x 2 factorial design, female Wistar rats consuming an ID + n-3 FAD diet preconception were randomised to receive an: 1) iron supplemented (Fe + n-3 FAD), 2) DHA/EPA supplemented (ID + DHA/EPA), 3) Fe + DHA/EPA, or 4) ID + n-3 FAD diet from gestational day 10 throughout pregnancy and lactation. Post-weaning, offspring (n = 24/group; male:female = 1:1) remained on the respective experimental diets for three weeks until postnatal day 42-45. Offspring born to female rats consuming a control diet preconception and an Fe+DHA/EPA diet throughout pregnancy and lactation served as non-deficient reference group (Control+Fe+DHA/EPA). Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry and bone strength using three-point bending tests. Only offspring in the Fe+DHA/EPA group had significantly higher spine and femur BMD, and higher femur stiffness than offspring in the ID + n-3 FAD group, and had similar spine BMD and femur stiffness as the Control + Fe + DHA/EPA group. Offspring in the Fe + DHA/EPA group further had significantly higher femur strength (ultimate load) than the other experimental groups, and a similar femur strength as the Control + Fe + DHA/EPA group. This study shows that only combined iron and DHA/EPA supplementation can prevent bone impairments in offspring of female rats consuming an iron and n-3 FA deficient diet preconception.