By Rachel Neifeld, RD, CDN

We’ve known for over twenty years that trans fats (man-made fats used to preserve the shelf life of foods) negatively affect our health, but new research is showing that it may also affect the health of our newborns. The study published in the American Journal of Clinical Nutrition found that as women’s intake of trans fat increased, so did the size of their babies.  

The study involved over 1,400 women in the Boston area who filled out dietary questionnaires during their first and second trimesters. Even after accounting for such factors as pre-pregnancy body weight, income, calorie intake, and education, the newborn’s weight increased as the women consumed more of this unhealthy fat.

But why is having a bigger baby harmful? 

The researches aren’t sure exactly what the findings mean, but larger-than-normal babies are more likely to be delivered by c-section, a surgery which increases a woman’s risk of infection, adhesions that could lead to future pregnancy complications, and increased blood loss. Another negative effect is that larger-than normal babies may have increased risk of diabetes and heart disease later in life.

What is clear is that trans fats hold no place in a healthy diet. Whereas we need some saturated fat and definitely unsaturated fats in our diet, we don’t need any trans fats. These are produced through a chemical process called hydrogenation, in which the structure of an oil is changed from its natural unsaturated form to a saturated one, making it solid at room temperature so that it becomes spreadable (like some margarines and some peanut butters) and have increased shelf life (as in some baked goods). The body doesn’t know what to do with these man-made trans fats so it makes sense that it probably won’t do anything good. In fact, this is the worst type of fat and it’s recommended that we keep trans fatty acid consumption as low as possible. Avoid a product if the ingredient list includes the words “partially hydrogenated.” Even if the label says “0 grams of trans fats,” if it’s partially hydrogenated it may have less than 0.5 grams per serving but this won’t be the case when more than one serving is consumed.

Even though the exact effect that increased trans fat consumption during pregnancy has on a newborn’s health is unclear, it is well known that trans fats should be avoided for the sake of the mother’s health. Posing health risks to the fetus is just another reason to nix the trans fats and choose more natural, nutritious foods that will increase your chance of having a healthy pregnancy and baby, not an unhealthy birth weight!

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