, finds the underlying mechanism behind the risk of obesity in the child due to the intake of high-fat diets of the mother during pregnancy and breastfeeding.
‘Changes in the nutritional and hormonal environment during perinatal period can predispose the offspring to obesity and its associated pathologies later on.’
Link Between Mother's Diet And Their Offspring's Weight
The western diet which is high in fat and sugar includes hamburgers, pizza, chocolates, soda, sweets. Regular intake of such foods can increase the risk of conditions such as obesity and diabetes.
Factors underlying obesity include how the food is metabolized and the tendency to overeat and seek out energy-rich foods. The brain reward circuitry and changes in these reward circuits can contribute to overeating.
The research team who studied the link between maternal food intake and weight gain in offspring found that rats who ate a junk food diet during pregnancy had heavier pups that strongly preferred the taste of fat straight after weaning.
The research team fed rats a high fat/high sugar diet (which they called the 'Western Diet'), or a balanced diet, during pregnancy and suckling. They monitored the mothers' pups straight after weaning, during adolescence and into early adulthood.
While a balanced diet in childhood seemed to reduce the pups' desire for fat, they nevertheless showed altered brain reward circuitry into adulthood.
Fat Preference Test
The pups from Western Diet mothers were a normal weight at birth, but they gained more weight during suckling and were abnormally heavy at weaning. This may have been caused by the Western Diet mothers producing richer milk or more milk.
The pups primarily ate a balanced diet once they were weaned, but at specific times the researchers allowed some of the pups to choose between tasting a fatty or non-fatty liquid. The liquid wasn't fatty enough to affect the pups, but allowed the team to assess their preference for fat.
When the team allowed the pups to choose between a fatty and non-fatty liquid, pups from Western Diet mothers strongly preferred the fatty liquid compared with pups from the balanced diet mothers
Later, when the team repeated this fat preference test with adolescent pups, they found that both groups showed a similar high preference for fat. Surprisingly, the pups from Western Diet mothers gradually lost their interest in fat after a few days. This might have been a compensatory mechanism to protect the pups from further exposure to fat. By adulthood, both types of pups had similar strong preferences for fat.
Changes in Rewarding Areas of Brain
The pups from Western Diet mothers also showed significant changes in their reward circuitry, including differences in a brain region call the hypothalamus and changes in gene expression associated with a neurotransmitter called GABA.
"Previous studies have shown that when pups from Western Diet mothers have unlimited access to junk food they maintain their preference for fatty food into adolescence," says Vincent Paillť, a researcher involved in the study.
"While the pups from Western Diet mothers in our study showed extensive changes in their reward circuitry, a balanced diet in childhood seemed to protect them from an increased fat preference at adolescence."
These findings could have implications for nutrition and obesity in human children in Western countries.
The team plan to further investigate the changes in reward circuitry caused by a maternal Western diet. "How these altered reward circuits integrate information could be different, and these pups might behave differently under stress or when they have free access to fatty food," says Paillť.
- Vincent Paillť et al., Perinatal Western Diet Consumption Leads to Profound Plasticity and GABAergic Phenotype Changes within Hypothalamus and Reward Pathway from Birth to Sexual Maturity in Rat, Frontiers in Endocrinology (2017)