Does maternal dietary mineral restriction per se predispose the offspring to insulin resistance?

Abstract

BACKGROUND: Maternal undernutrition is hypothesized to predispose the offspring to disease in adult life. The relevance of maternal macronutrient deficiency has been well studied but not that of micronutrients. OBJECTIVE: To assess the effect of maternal dietary mineral restriction per se on oral glucose tolerance (OGT), insulin resistance (IR) and fat metabolism in offspring. DESIGN: Female weanling Wistar/NIN rats received a control or a 50% mineral-restricted (MR) diet for 12 weeks, by which time MR rats had lower plasma Fe, Zn, Mg and Ca concentrations. Following mating with control males, a third of the MR dams were shifted to the control diet from parturition. Half of the pups born to the remaining MR dams were weaned onto the control diet while the other half continued on the MR diet. RESULTS: Pregnant MR dams had a higher abortion rate, body weights of their pups at birth and weaning were lower and rehabilitation had no beneficial effect. No offspring had impaired OGT, and IR status was comparable among different groups on postnatal days 40, 70, 100 or 180. Compared with controls, total body electrical conductivity measurements indicated significantly higher body fat %, lower lean body mass and fat-free mass in MR offspring besides elevated plasma triacylglycerols. Mineral rehabilitation from parturition or weaning had little effect on these changes, which did not appear to be due to increased oxidative stress. CONCLUSIONS: Maternal MR per se resulted in an increase in body fat and in plasma triacylglycerol concentrations in the offspring. These changes had, however, no discernable effect on insulin sensitivity over the first 180 days of life.