Did you know that a ban on trans fats in restaurants in New York state has been linked to fewer heart attacks and strokes? In a study published in April 2017 in JAMA Cardiology, researchers found that after bans were implemented, there was a 6.2 % decline in heart attacks and strokes in New York counties. The decline in hospital admissions for heart attack and stroke reached statistical significance three or more years after restrictions were implemented. It is worth to mention here, according to WHO statistics, coronary artery disease and stroke are the world’s leading causes of death.
So what exactly are the trans fatty acids and why they have such bad reputation?
If you are one of those people who liked to take a nap during a chemistry class, maybe now it’s a good time to repeat the lesson about isomers. Isomers are compounds with the same chemical formula but different structures. So if we apply this knowledge to organic fatty acids in nature, unsaturated fatty acids (fatty acids that contain double bonds between hydrocarbon chains), generally occur in cis configuration.
Trans fatty acids are also a type of unsaturated fat, but the two carbon atoms in the chain that are bound next to either side of the double bond occur in a trans configuration. We can find trans fatty acids naturally in some food, but in very small amount (mostly in some meat and dairy products). These trans fats could actually be beneficial for our health as some studies have shown.
But unfortunately, most trans fats occur in our food artificially through food processing. They are created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid. Partial hydrogenation of the unsaturated fat converts some of the naturally occurring cis double bonds into trans double bonds during the process. The food industry uses trans fatty acids because of their desirable properties: they give food a good texture and desirable taste and also help stabilize foods for storage. Originally, they were created as an alternative to saturated fats, which are connected with the occurrence of cardiovascular disease (just remember the famous butter- versus-margarine debate).
The problem with trans fats is that trans fatty acids increase plasma concentrations of low-density-lipoprotein cholesterol (LDL-“bad cholesterol”) and reduce concentrations of high-density-lipoprotein cholesterol (HDL-“good cholesterol”). Also, increased consumption of trans fats leads to larger vascular wall thickness with narrowing of the blood vessel. So persons who consume greater amounts of trans fatty acids have higher risks of coronary diseases. Increased trans fat intake is also associated with elevated levels of inflammatory markers and the risk of developing type 2 diabetes.
But the biggest problem of all to my opinion is that people are completely unaware of the presence of trans fatty acids in their food. This is not just a question, will you eat butter or margarine for breakfast (for information only, the food industry has developed trans-fat-free options), but the problem is trans fats are present in food you wouldn’t think of: cookies, crackers, baked goods, fried foods, pizza, microwave popcorn, and some stick margarines all contain trans fatty acids.
So read the products’ labels and look for phrases “partially hydrogenated vegetable oil”, “partially hydrogenated fats or oils” or “shortening”. Even if trans fat is listed on the label as “zero trans fat”, some trans fats could be still present in the product.
In the USA, the Food and Drug Administration has banned the use of trans fatty acids in food and by June 18, 2018, manufacturers must ensure that their products no longer contain partially hydrogenated oils. But at the moment, in the rest of the world, whether or not to reformulate products or inform consumers about trans fats is a decision of the food business operators. If you would like to know if your country is obligated to list trans fats on the labels read this report:
“…only a small fraction of people seems to be concerned about TFA intake.“
Finally, development of coronary artery disease is influenced by many factors, including family history, age, obesity, high blood pressure, smoking, etc. Consumption of trans fatty acids is only one link in the chain, but for starters, we should all pay more attention to trans fats in our food and try to avoid them as much as possible.