High sugar diet impairs metabolic health post-pregnancy, study finds

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A high sugar diet during pregnancy alters levels of progesterone and dopamine in the brain, which may lead to behavioral changes that can affect care of offspring and motivation, as well as increasing the risk of diabetes and liver disease, according to a new study published in the Journal of Endocrinology.

For the study, researchers led by Daniel Tobiansky, PhD, investigated the effects of a high sugar diet on hormone levels and markers of metabolic function in female rats. The rats were maintained on a high sugar diet, equivalent to 25 percent of their total calorie intake, covering a period 10 weeks prior to mating, as well as throughout pregnancy and lactation.

Markers of metabolic health indicated that their glucose regulation was impaired and that they had fatty livers, although their body weight was not different from rats on normal diet, the researchers said. Levels of progesterone were increased whilst markers of dopamine function indicated that its activity in the brain was altered.

Pregnant rats on a high sugar diet, equivalent to a typical Western diet, had increased progesterone levels, a hormone important for healthy pregnancy and lactation, and changes in the dopamine system, a neurotransmitter key in motivation, reward, and mood. They also showed signs of prediabetes and fatty liver disease.

The findings suggest that sugar consumption during pregnancy may have serious, long-term health risks for the mental health of both mothers and pups, beyond the established risks for diabetes and heart disease, Tobiansky said.

“Beyond the established metabolic effects of high sugar intake, our data suggest that it may also have long-term harmful effects on mental health and maternal care,” he said in a statement. “Progesterone is important for healthy pregnancy and lactation, whilst dopamine signaling is key for reward, learning, and motivational behaviors. Taken together, these findings suggest that maternal behavior… could be negatively affected.”

The researchers suggest public and health professionals follow the recommendations from the World Health Organization and the American Heart Association. They both encourage limiting added sugars to less than 10 percent of daily calories, and for maximum benefit, to 5 percent. This likely has benefits for metabolic health, as well as hormone and brain health, the researchers said.