Scientists at two ARS-funded nutrition research centers are examining how maternal influences of the unborn child and the developing newborn could increase the risk that the child would become an overweight or obese adult. In turn, that adult would have a higher risk of obesity-related afflictions such as type 2 diabetes or cardiovascular disease.
Investigators at the ARS Arkansas Children’s Nutrition Center in Little Rock looked at weight gains among rat pups whose mothers, called “dams,” were either lean or overweight (from overfeeding) at the time of conception and during pregnancy. Researchers mated the lean or overweight female rats with lean males. The pups were nursed only by normal-weight dams to make sure that the pups’ exposure to their mother’s obesity occurred only in the womb. All pups were of normal weight at birth and at weaning. When the weaned offspring were given free access to an unlimited amount of high-fat rations, the offspring of overweight dams gained significantly more weight, and more of that weight as fat, than did the offspring of lean dams.
“This occurred despite the fact that the offspring of overweight dams ate the same amount of high-fat food as the offspring of lean dams,” the researchers said. “Our study strongly suggests that exposure to the mother’s obesity—while in the womb—results in programming of the offspring’s body-weight-control mechanisms. The dams’ obesity alone was sufficient to significantly increase the pups’ susceptibility to obesity.”
If proven true for humans, the findings would underscore the need for aspiring mothers to achieve a healthy weight before becoming pregnant and to gain only the recommended amount of weight during their pregnancy.
At the ARS Children’s Nutrition Research Center at Baylor College of Medicine in Houston another researcher is studying the “epigenetic mechanism” link to obesity. The researchers studied a population of genetically similar laboratory mice known for their genetic tendency toward obesity. The findings suggest that “an epigenetic mechanism may act to increase the severity of obesity from one generation to the next.” This “transgenerational amplification of obesity” occurred in three successive generations of mice. Specifically, overweight dams gave birth to even-more-overweight offspring, the females of which gave birth to even heavier pups, and so on, through generation three.
Reported in the International Journal of Obesity, the study showed that the mothers’ obesity apparently induced changes in the expression of genes that control the formation of the pups’ body-weight-regulating mechanisms. That likely took place in the womb and perhaps in the weeks thereafter, setting the pups on the path to obesity.
Sources: Natural Products Marketplace