trans fats in pregnancy

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Trans fats are dangerous and are everywhere; they are the most commonly used fats in processed and ready-made food. They are a basic ingredient for breads, pastries, ready meals, desserts and sweet or savory spreads. Think of processed vegetable oils and frying oils, while margarine and most of the easily spreadable butter-like products contain significant amounts of trans fats as well.

Since they are so popular, avoiding them is not easy. Almost everybody eats some, including pregnant women. And this is the problem. Knowing that diet during pregnancy can have a lasting effect on the health of the baby, often persisting throughout adulthood, should we worry about consumption of trans fats during pregnancy?

The short answer is yes, we definitely should. Because trans fats are not only notorious for the proven associations with heart disease but like all the fatty substances, after digestion, they become part of cellular membranes, especially in the brain, directly affecting how it functions. During pregnancy, this happens to both the mother and her unborn baby.

Trans fats may irreversibly change brain functions

Existing evidence, from animal studies, reveals that when trans fats are consumed by pregnant mothers on a daily basis, they are incorporated in the baby´s brain cells, altering behavior and emotional responses. Researchers from Brazil investigated this problem and found that when pregnant mothers are supplemented with trans fats throughout pregnancy and lactation, their baby becomes hyperactive, showing a manic behavior similar to bipolar disorder, a recognized psychiatric problem. Memory problems and increased emotional reactions after exposure to stressful conditions were also noted.

At the same time, maternal consumption of trans fats resulted in significantly more oxidative damage in the brain cells of the babies. On the other hand, fish oil (rich in healing omega 3s) supplementation has the exact opposite effect: protection of the baby´s brain from oxidative damage, memory problems, emotionality and manic behavior. Babies whose mother ate fish oils instead of trans fats during pregnancy and lactation were emotionally stable under stress and their brains were significantly protected from oxidative damage.

If you casually browse the references at the end of this article, you will see the weird term “cross-generational” in the title of the specific animal studies (1 and 2) I am talking about. This means that the effects of trans fats are not limited only to the generation who consumes the trans fats (the mother), but in fact it permanently affects the next generation as well (the baby) – a true & rare case of a cross-generational effect that you dont really expect from your daily doughnut…

Other effects of trans fats

Since the 90s we know that trans fats are bad for heart health. Here is what the Mayo Clinic has to say about these artificial fats [5]:

Trans fat is considered by many doctors to be the worst type of fat you can eat. Unlike other dietary fats, trans fat — also called trans-fatty acids — both raises your LDL (“bad”) cholesterol and lowers your HDL (“good”) cholesterol. A high LDL cholesterol level in combination with a low HDL cholesterol level increases your risk of heart disease, the leading killer of men and women.

Despite the fact that trans-fats have been found to sabotage cardiovascular health, they remain the oils of choice for food corporations, thanks to two very desirable properties: they are cheap and have a long shelf life. Products made with trans fats go rancid much later, compared to alternatives made with natural fats. Trans fats go through extensive industrial processing at high temperatures and with different chemical solvents, which remain in small quantities in the final product. This process is responsible for their unnatural properties and of course, their toxic nature.


The available evidence suggests that systematic consumption of trans fats during pregnancy and breastfeeding can affect the cognitive and behavioral patterns of the next generation. Despite the widespread use of trans fats and the worrying evidence from animal studies, there is a definite gap in scientific research in humans. Given the tremendous industrial vested interests it is unlikely that we will ever see in-depth research on this critical topic and we shouldn’t wait for it anyway. We now know that trans fats do not just undermine cardiovascular health. Like most unhealthy or toxic substances, they affect multiple systems of the body and compromise health in many seemingly unrelated ways.

If we are going to invest in the wellbeing and health of our children, it is common sense to work with the evidence we have in our hands right now and advice pregnant and breastfeeding women to actively avoid foods containing trans fats. The good news is that while several natural fats are essential for life, trans fats are not. They are entirely artificial substances and a convenient solution for food industries, which effectively threaten the physical, mental and emotional wellbeing of the present and the next generation.


[1] Trevizol F, Roversi K, Dias VT, Roversi K, Barcelos RC, Kuhn FT, Pase CS, Golombieski R, Veit JC, Piccolo J, Pochmann D, Porciúncula LO, Emanuelli T, Rocha JB, Bürger ME. 2015. Cross-generational trans fat intake facilitates mania-like behavior: oxidative and molecular markers in brain cortex. Neuroscience. 286:353-63.

[2] Trevizol F, Dias VT, Roversi K, Barcelos RC, Kuhn FT, Roversi K, Pase CS, Golombieski R, Veit JC, Piccolo J, Emanuelli T, Rocha JB, Bürger ME. 2014. Cross-generational trans fat intake modifies BDNF mRNA in the hippocampus: Impact on memory loss in a mania animal model. Hippocampus.

[3] Pase CS, Roversi K, Trevizol F, Roversi K, Kuhn FT, Schuster AJ, Vey LT, Dias VT, Barcelos RC, Piccolo J, Emanuelli T, Bürger ME. 2013. Influence of perinatal trans fat on behavioral responses and brain oxidative status of adolescent rats acutely exposed to stress. Neuroscience. 247:242-52.

[4] American Heart Association. Trans Fats.

[5] Mayo Clinic. Trans fat is double trouble for your heart health.