The old adage that we are what we eat may need a little alteration, according to the findings of a recent study.  It seems likely now that we are what our mothers ate during pregnancy.  And the effect of the mother’s diet may be strongest in female offspring.

Research findings published last year showed that when pregnant laboratory rats ate the equivalent of a junk-food diet, one high in sugar, salt, and fat, her offspring were more likely to eat excessively and develop a preference for the same junk foods.  Pregnant rats fed a healthy diet gave birth to offspring that did not develop these same tendencies.

Following up on that study, researchers have discovered now that the effects of the mother rat’s diet on her offspring lasted beyond adolescence, even after the offspring were weaned off the junk foods.  The study indicates the mothers diet during pregnancy affects the offspring’s ability to metabolize food and may influence long-term health of her young.

For the study, both phases of which were conducted by the same team of researchers at the Royal Veterinary College in London, female rats were fed a diet high in processed foods which included doughnuts, sweets, biscuits, crisps, and muffins during pregnancy and lactation.  This group was compared to a control group fed a diet consisting of healthy rat feed.

In the offspring raised on junk foods, cholesterol and triglyceride levels were higher than those in the healthy, control group.  Elevated levels of cholesterol and triglycerides, fatty substances in the bloodstream, indicate an increased risk of developing heart disease.  These same rats had higher levels of insulin and glucose, too, both indicators of the threat of type 2 diabetes development.

After adolescence, the junk food-eating offspring remained fatter than the control group, with an alarming amount of the fat being concentrated around the kidneys, called perirenal fat, which signals insulin resistance and the potential for developing type 2 diabetes.

Even though rats are happy eating the same foods people regularly eat, including the junk foods, rats are not people although fundamental biology is similar in many systems.  And studies in humans have shown that the more weight a woman gains during pregnancy, the more likely her children will be obese, leading researchers to suggest good reason for the assumption that the effects of the junk food diet in rats is likely to occur in humans as well.

The research team expressed surprise at how the gender of the offspring determined how the mother’s poor diet affected him or her.  Male offspring had higher insulin levels but normal glucose levels.  Female offspring were the opposite, with high glucose levels but normal insulin levels, and they were more likely to be overweight.

Female offspring also had higher levels of the hormone, leptin, important in the regulation of appetite.  Females are more likely to be sensitive to leptin while males are more likely to be sensitive to insulin.  Both leptin and insulin are important for metabolism and sensitivity to either can lead to resistance, which can lead, in turn, to overeating and the resulting health issues.

Speaking on behalf of the research team, Dr. Pat Goodwin said that although pregnancy can be a trying time, it remains important for mothers to know that what they eat during that critical time affects their offspring and likely has long-term consequences.  Goodwin is head of Pathogens, Immunology and Population Health for the Wellcome Trust, which funded both studies.  The follow-up study, involving the health status of the adolescent offspring, has been published in The Journal of Physiology.

Source: Wellcome Trust