Washington: A new study on mice shows that exposure to 'lead' through their mothers could cause obesity.
Researchers at the University of Michigan claim that mice whose mothers were exposed to the chemical, had an 8-10 percent increase in weight.
Dana Dolinoy, senior author of the study said that the data supported the obesogen hypothesis that toxicant exposures in the womb contribute to the higher rate of obesity.
In the study, mothers were exposed to lead through drinking water two weeks before mating then throughout pregnancy and nursing. Their litters were then measured at 3, 6 and 9 months of age for energy expenditure, spontaneous activity, food intake, and body weight and composition. At age 9 months they were tested for glucose tolerance. Researchers determined sex specific impacts on all of the measures.
The researchers found:
Starting in early life, males in the two highest exposure groups outweighed the controls, a trend consistent from youth to adulthood.
An increase in body fat at all dosages showed up in males at 3 months of age.
Overall, both sexes exposed to the highest dose ate more than the control group, with males eating more at 6 months of age and female consumption increasing at 9 months of age.
Exposed males showed impaired insulin levels at 9 months of age.
Although females appeared more active for a time, there was no significant increase in spontaneous activity for either sex.
In terms of energy expenditure, both sexes showed the expected decline in oxygen consumption and carbon dioxide production as they aged, but the exposed females had higher energy expenditure at 3 months of age and the exposed males had lower energy expenditure at 9 months of age.
Researchers used the wide range of exposure levels to more closely match with human experience. Baby boomers and other older adults once were exposed to levels much higher, on average, before some of the bans on lead.
The study is published in PLOS-ONE.