Maternal Dietary Vitamin Restriction Increases Body Fat Content but Not Insulin Resistance in WNIN Rat Offspring Up to 6 Months of Age

Aims/hypothesis: Epidemiological evidence suggests that some adult diseases like insulin resistance syndrome and diseases associated with it originate in fetal life. The role of maternal macronutrient malnutrition but not of micronutrients in the fetal origin of adult disease is well studied. We hypothesise that chronic maternal vitamin restriction predisposes the offspring to insulin resistance syndrome.

Methods: Female weanling Wistar/NIN rats received a control diet ( n=6) or a 50% vitamin-restricted diet ( n=14) for 12 weeks and mated with control males. Four dams on the restricted diet were shifted to the control diet from parturition. Pups born to the remaining 10 dams on the restricted diet were weaned on to control diet or continued on the restricted diet. All groups had 8 male pups from weaning onwards.

Results: Birthweights of pups were comparable among different groups. Weaning body weights were low in the restricted diet group, but on rehabilitation they caught up with control animals by post-natal day 100. None of the pups had impaired oral glucose tolerance and their insulin resistance status was comparable on days 40, 70, 100 and 180. Compared with offspring on the control diet, offspring on the restricted diet had a significantly higher percentage of body fat and higher plasma triglycerides, as well as lower lean body mass and fat-free mass. They also had increased oxidative stress. Rehabilitation from parturition or weaning prevented the changes in body fat percent, lean body mass, fat-free mass and oxidative stress.

Conclusions/interpretation: Since changes in adiposity and fat metabolism are considered forerunners of insulin resistance syndrome, our observations suggest that maternal dietary vitamin restriction predisposes the offspring to insulin resistance syndrome in later life.