Can eating too much fat in pregnancy harm your baby?



According to a group of researchers who completed a study on monkeys, eating too much fat during pregnancy may be harmful to a pregnant woman’s developing fetus.

The findings build on previous research with pregnant women, which showed that excessive weight gain or high blood sugar levels can overwhelm the fetal metabolism, setting the stage for obesity and related health issues like diabetes.

The Japanese macaque monkeys were fed a fat-rich diet similar to that of the average American. Fat accounted for 32% of total calories. Many of the monkeys gained weight and became obese after two years, but some remained healthy. In either case, a high-fat diet was found to be harmful to developing fetuses.

The offspring began to show a pattern of liver damage while still in the womb, similar to what happens in obese people. Their livers had three times the normal amount of fat in them. Stress and tissue damage caused substances to accumulate in the fetal livers.

And it wasn’t just the liver that suffered. Following up on the findings, researchers discovered damage to the pancreas and brain tissue of fetal monkeys exposed to high fat levels. Within 90 days of birth, the monkeys had gained twice the normal proportion of body fat.

The risk was partially reversed when mothers reduced their fat intake. The adult females were switched to a normal diet in the fifth year of the study. A significant number of the monkeys conceived again, and their offspring had reasonably less liver fat amounts than monkeys born to mothers who had never been exposed to a high-fat diet.

Because human and monkey fetuses do not develop a fat storage system until late in pregnancy, they are vulnerable to fat overload. Excess fatty acids are stored in white adipose tissue in infants and adults, but this specialized tissue does not appear until late in the third trimester of fetal development.

As a result, the fetus is extremely vulnerable to lipotoxicity, a condition in which the mother’s excess fats pass through the placenta and accumulate in the fetal liver, muscles, and pancreas, causing harmful inflammation.

The study also found that children born to mothers with elevated blood sugar, or gestational diabetes, during pregnancy were about 80 to 90 percent more likely to be overweight or obese at age 7 than children born to mothers with normal blood sugar in a 2007 study involving over 9,000 women.

That’s not all. It also found that when women were treated for gestational diabetes, their children were no more likely than other children to be overweight or obese.

Both human and animal studies suggest that we can program the fetus for health. The findings emphasize the importance of eating a healthy diet and managing weight gain during pregnancy for women.

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