Trans Fat and Cardiovascular Health Risks

4th November 2019
Do you know that trans fats represent a big threat to your health? Many people consume more than the recommended amount; so make sure you know which foods harbor these unhealthy fats.

You have to know several aspects of fat in order to understand what trans fat is, how it forms and the risks it implies for your health. In today’s post, learn everything you need to know about this pressing health topic.

Trans fat explained by biochemistry

Fatty acids (FA) are lipid biomolecules. They’re comprised of a long hydrocarbon chain that has a carboxylic group on each end.

Each carbon atom joins to the next with a simple or double bond. The length of the chain depends on the number of carbon atoms present. In addition, the type of bonds between the atoms determines the characteristics of the molecule.

Types of fatty acids

Saturated

Saturated fatty acids don’t have double bonds between the carbon atoms. They often form long chains and are solid at room temperature.

Unsaturated

Unsaturated fatty acids have at least one double bond in their structure. They can vary depending on the number of double bonds they have:

  • Monounsaturated fatty acids: these types of unsaturated fatty acids, such as oleic acid, only have one double bond in its structure.
  • Polyunsaturated fatty acids: polyunsaturated fatty acids contain various double links in their structures. Linolenic acid is a great example.

What are trans fatty acids?

Trans fatty acids (TFA), or trans fat, are unsaturated fatty acids that come from an industrial origin. Most trans fatty acids form when liquid fats are solidified, which is a process known as “hydrogenation”.

In scientific literature, articles often refer to TFAs as “partially-hydrogenated” or “trans-cholesterol fats”. The term “trans” refers to the molecule’s structural makeup.

trans fat burger

Characteristics of trans fatty acids

In the 1900s, the demand for fat increased and pushed researches to look for ways to make fat more stable. Until then, people stored fat for long periods or time, which led to it to oxidize and rot. The results were generally foul odors and flavors.

In response to the demands, Wilhelm Normann patented oil hydrogenation in 1902. He aimed to increase the shelf-life of food products and create solid and semi-solid fats.

Fatty acids with double trans bonds have a higher fusion point than other fatty acids. Thus, trans fatty acids form solids while others are liquid at room temperature.

Where do trans fatty acids come from?

Natural sources

Trans fat can come from bio-hydrogenation of grass or hay, which is a process that that takes from in the rumen of ruminate animals. As a result, trans fat is present in the meat and milk of all ruminate animals. This kind of trans fat represents 3 percent to 6 percent of all-trans fat.

Industrial origin

But the majority of trans fatty acids are a result of industrial processes:

  • Deodorization (odor-eliminating process) of polyunsaturated oils (plant and fish).
  • Heating frying oils.
  • Partial or total industrial hydrogenation. This process produces solid fats and partially-hydrogenated oils.

You can find these industrially produced fats in highly-processed food products such as:

  • Commercial baked goods.
  • Cakes and tarts.
  • Fast food.
  • Cookies.
  • Fried or breaded foods.
  • Pre-cooked foods such as pasta or pizza.

What’s the difference between natural and industrial trans fats?

There’s no difference. The European Food Safety Authority came to the conclusion by analyzing the isomers of different food products (various animal meats, partially-hydrogenated oils…) and observing no difference between them.

All of the studied food products had the same number of isomers; the proportions, however, differed. In the natural sources, vaccenic acid was the predominant acid whereas elaidic acid was more prominent in the partially-hydrogenated oils.

Trans fatty acids and cardiovascular disease

At the end of the 90s, 70 percent of the fats consumed in the United States were hydrogenated. The high percentage raised an alarm in health circles and they began to study the relationship between the consumption of these fats and cardiovascular diseases.

Through the studies, researchers found that trans fatty acids are linked to an increase of LDL (bad) and a decrease of HDL (good) cholesterol. In addition, they also found that trans fat created resistance to insulin. Trans fat is linked to a higher risk of suffering from diabetes, high blood pressure, and cardiovascular diseases.

Furthermore, a systemic review from the New England Journal of Medicine concluded that following a diet in which more than 2 percent of the total energy derived from trans fat created a 25 percent higher risk of cardiovascular problems.

trans fat fries

Current legal issues regarding trans fat

Europe didn’t have actual numbers on how much trans fat was being consumed until the 1999 publication from the Transfair study. It stated that people consumed an average of 2 to 17 grams of trans fat a day. In Spain, the numbers showed a safe amount of consumption (2.1 g of trans fat per day).

The Commission Regulation (EU) 1169/2011 obliges food products to have a nutrition label. However, the law doesn’t force manufacturers or providers to include trans fat content. But there are some countries in the EU that have included it in their national laws.

In Spain, companies are encouraged to reduce trans fat content, but there are no enforced laws.

The World Health Organization (WHO) published Replace, in which they specify the steps to eliminate trans fats from industrial processes in the global food supply. Furthermore, the WHO also recommends reducing total daily trans fat consumption to 1 percent of the total daily energy intake.

  • EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies), 2010. Scientific Opinion on dietary reference values for fats, including saturated fatty acids, polyunsaturated fatty acids, monounsaturated fatty acids, trans fatty acids, and cholesterol. EFSA Journal 2010;8(3):1461, 107 pp. https://doi.org/10.2903/j.efsa.2010.1461
  • Hulshof KF, Van Erp-Baart MA, Anttolainen M y cols. Intake of fatty acids in western Europe with emphasis on trans fatty acids: the Transfair Study. Eur J Clin Nutr 1999, 53:143-157
  • Mozaffarian, D., Katan, M. B., Ascherio, A., Stampfer, M. J., & Willett, W. C. (2006). Trans fatty acids and cardiovascular disease. New England Journal of Medicine, 354(15), 1601-1613
  • OMS (2018). Eliminate industrially-produced trans-fatty acids
  • Unión Europea, D. O. Reglamento (UE) No 1169/2011 del Parlamento Europeo y del Consejo, de 25 de octubre de 2011, sobre la información alimentaria facilitada al consumidor. DOUE de 22 de noviembre de 2011; L 304: 18-63
  • Hulshof KF, Van Erp-Baart MA, Anttolainen M y cols.: Intake of fatty acids in western Europe with emphasis on trans fatty acids: the Transfair Study. Eur J Clin Nutr 1999, 53:143-157.