Effect of maternal dietary glycemic index on offspring metabolic programming in mice
Charles Perkins Centre, School of Life and Environmental Sciences, University of Sydney, Australia.
The glycemic index (GI) is a measure of the quality of carbohydrate with regards to its effect on blood glucose levels, with low GI diets being associated with improved metabolic health, both in humans and rodents. However, present research is unable to elucidate the mechanism(s) responsible, largely due to confounding factors associated with low GI diets. Isocaloric rodent diets differing only in the base sugar carbohydrate (high GI: glucose, sucrose; low GI: isomaltulose, fructose) were constructed such that fibre content was well controlled, but GI varied, as confirmed through in vivo GI testing in mice. To examine the effect of maternal dietary GI on offspring metabolic programming, embryos and pups born of C57BL/6 mothers fed these diets or chow were compared. Preliminary results show embryos of chow-fed mothers were significantly heavier than embryos from glucose and isomaltulose-fed mums, and had significantly heavier livers and spleens than embryos of all other groups. Male pups were heavier, leaner, and more glucose intolerant than females across all diets. While we observed no differences in bodyweight and other variables amongst female pups, male pups exhibited greater variation in these parameters and were affected by maternal and postnatal diet. Chow, glucose and sucrose male pups were heavier than isomaltulose and fructose pups from weaning to 12 weeks. Fructose and glucose male pups had higher insulin peaks at 12 weeks of age, while there was no difference in basal blood glucose levels. Maternal dietary sugars exhibit a limited effect on offspring metabolic health, but only in male pups. Compared with chow, the sugar-diet pups were lighter, fatter and less glucose tolerant.