EFFECTS OF DIETARY CARBOHYDRATES ON MINERAL METABOLISM IN LACTATING DAMS AND THEIR PUPS

Abstract

Dramatic increases in fructose (F) consumption in the last 40 y have been tightly linked to obesity, insulin resistance and other metabolic abnormalities in adults. However, there is no information about the effects of F on maternal and fetal health. To evaluate the specific effects of excessive F and glucose consumption during gestation and lactation on dams and their litters, 3 groups of female rats were fed isocaloric, isolipidic 60% glucose, F or starch diets for 40 d, from day 2 of gestation to end of lactation. Compared to dams fed glucose and starch, dams fed F had lower rates of intestinal transepithelial Ca transport as well as lower levels of intestinal Ca and calbindin 9K protein, plasma Ca and plasma 1,25‐vitamin‐D. Dams fed glucose or F exhibited lower rates of transepithelial Pi transport, levels of plasma Pi, bone mineral content and bone mineral density (BMD). These marked perturbations in mineral homeostasis resulted in modest decreases in BMD as well as growth rates of pups from F‐fed dams. Our novel findings clearly show that over‐consumption of F and perhaps glucose during pregnancy and lactation impairs bone health of the dams because of decreases in active intestinal Ca and Pi transport caused by impaired production of 1,25‐vitamin D. Dams may mobilize bone Ca and Pi stores to dampen perturbations in mineral homeostasis transmitted to the offspring. (NIH RDK075617, NSF 722365)