Pregnant women who consume trans fats in snacks, sandwich cookies, fast food and other unhealthy foods are more likely to give birth to larger babies, according to a recent U.S. study.
The study, published in the American Journal of Clinical Nutrition, was conducted with 1,400 pregnant and it was found that the higher intake of trans fats - they increase LDL cholesterol, known as "bad" cholesterol and lowers levels of HDL cholesterol beneficial to the heart - during the second trimester of pregnancy, the greater the newborn.
The study not only proves that trans fat is able to boost fetal growth, and even if he did, there would be no way of knowing how it could be harmful to the baby. But there are risks associated with having a larger baby than normal, she said Juliana Cohen, School of Public Health at Harvard in Boston (USA).
Big babies need to be removed from the womb by cesarean sections and studies have shown that they may have an increased risk of diabetes and heart disease later in life, Cohen said.
It is prudent to limit consumption of trans fats in the diet anyway, "she said.
Trans fats are found in foods containing partially hydrogenated oils, including many packaged foods, baked and fried foods like chips, crackers and cookies, as well as much of the fast-food options.
Some meats and dairy products contain natural trans fats, but people end up eating most of these fats from artificial way - today some food producers and restaurants have reduced or cut the use of trans fats because of the bad publicity around it.
The latest study was based on women in the Boston area, who delivered their babies between 1999 and 2002. The women filled out food questionnaires during their first and second trimesters of pregnancy.
The relationship between higher intake of trans fat and baby's size at birth remained even when researchers took into account factors such as body weight before pregnancy, income, education and calorie intake.
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They calculated that for every increase of 1% trans fat compared to carbohydrates in the daily diet of the mother, the baby's fetal growth increased slightly.
Unfortunately, Cohen added, these types of foods are often those women most desire during pregnancy.