Women who consumed a diet high in animal fat and cholesterol before pregnancy were at higher risk for gestational diabetes than women whose diets were lower in animal fat and cholesterol, according to researchers at the National Institutes of Health and Harvard University. The findings appear online in the American Journal of Clinical Nutrition.

Women whose diets were high in total fat or other kinds of fats but not in animal fat or cholesterol did not have an increased risk. The increased risk for gestational diabetes seen with animal fat and cholesterol appeared to be independent of other, dietary and non-dietary, risk factors for gestational diabetes, the researchers said. For example, exercise is known to reduce the risk of gestational diabetes.  Among women who exercised, however, those who consumed higher amounts of animal fat and cholesterol had a higher risk than those whose diets were lower in these types of fat.

The researchers concluded that changing the source of 5% of dietary calories from animal fat to plant-derived sources could decrease a woman's risk for gestational diabetes by 7%.

Researchers used information from more than 13,000 women participating in the Nurses' Health Study II.  The women were 22 to 45 years old when they enrolled in the study.  Every two years they responded to questions on their general health, pregnancy status, and lifestyle habits, such as consuming alcohol or smoking.  In addition, every four years they completed a comprehensive survey about the kinds of food and drink they consumed.

About 6% of the participants reported having been diagnosed with gestational diabetes. The researchers calculated the amount of animal fat in participants' diets as a percentage of total calories and divided participants into five groups based on those percentages.  Then the researchers compared the risk for developing gestational diabetes for each group. Women in the highest quintile of intake had almost double the risk for gestational diabetes compared to women in the lowest quintile.  

They also observed that women in the highest quintile for cholesterol consumption were 45% more likely to develop gestational diabetes than were women in the lowest quintile.

The research was also funded by the National Cancer Institute and the National Institute of Diabetes and Digestive and Kidney Diseases.