Trans fatty acids, usually called trans fats, are a type of unsaturated fat that cause harm to the body and may lead to serious disorders, including heart disease, metabolic imbalances and inflammation.
Nutritional experts hold varying opinions about what constitutes a healthy diet, but everyone agrees avoiding trans fats is wise.
The consensus has inspired governments worldwide to update regulations in an attempt to reduce the amount of trans fats used in commercial foods and minimize consumer exposure.
Americans eat only about a quarter of the trans fats they did in 2003 (1), but small amounts are still allowed in processed foods, and manufacturers find the longer shelf life and low cost of trans fats attractive. This can add up to serious health risks for consumers.
Even though the dangers of trans fats have been known for years, the Food and Drug Administration only recently revoked the GRAS (Generally Recognized As Safe) designation for trans fatty acids.
Chemistry 101: the Composition of Fats
The molecular structure of fatty acids affects our bodies in different manners.
Saturated fats like butter and coconut oil have only a single hydrogen bond at the molecular level. Unsaturated fats have at least one double bond with hydrogen.
In most unsaturated fats, the bonds between molecules occur on the same side, but in trans fats, the bond is formed on opposite sides.
Our bodies react unfavorably in a biological sense to these opposing double bonds, essentially making trans fats toxic and dangerous.
There are two kinds of trans fats: artificial and natural.
Natural trans fats are found in products from ruminant animals such as cattle, goats and sheep. These ruminant trans fats form in the animal’s stomach during the process of digesting grass.
Industrial or hydrogenated fats are artificial, created by using high pressure to force hydrogen molecules into vegetable oils. The process alters the molecular structure and transforms the liquid oil into a solid, similar to the texture of saturated fat. (6) Shortening used in baked goods is an example.
Eating Trans Fats is Risky Business
A number of trials and studies have been done in recent years to establish just what kind of health damage trans fats inflict. We’ll take a look here at four detrimental effects on human health that have been well-documented.
- Heart Disease
High cholesterol readings are an important marker for an increased risk of developing heart disease. In the clinical trials we’ll discuss here, cholesterol levels were measured for participants who replaced carbohydrates (at 1% of calories consumed) with trans fats.
While both HDL and LDL cholesterol levels usually rise when people eat other fats, trans fats raise only LDL, the “bad” cholesterol. (7)
The same response occurs when other fats (rather than carbohydrates) are replaced by trans fats. (8)
- Diabetes and Insulin Sensitivity
There are some mixed results from studies of associations between diabetics and trans fat consumption. A large trial with 80,000 women showed those who ate the most foods containing trans fats had a 40% higher risk of developing diabetes. (12)
Results from a number of studies examining the effect of trans fats on risk factors for developing diabetes (such as elevated blood sugar levels and reduced insulin sensitivity) were inconclusive.
Chronic western diseases like diabetes, heart disease, metabolic syndrome and arthritis have a common denominator: inflammation. When inflammation itself becomes chronic, serious disease is likely to be the next step.
Two of the three studies on links between inflammation and trans fat consumption showed an increase in inflammatory markers. (18, 19) The third study replaced butter with margarine in test subjects’ diets, with no discernible changes in inflammation. (20)
- Blood Vessels
Research suggests the consumption of trans fats damages the inside lining of blood vessels, or endothelium. Artery dilation was negatively impacted by 29% when test subjects replaced saturated fats with trans fats for 4 weeks. (23)
Animal studies showed increased markers for endothelial dysfunction when monounsaturated fats and carbohydrates were replaced with trans fats. (24)
The Bottom Line
With new guidelines regulating the use and sale of trans fats in commercial foods, researchers may find it difficult to recruit participants willing to eat the amount of trans fats necessary for further studies.
But many people are still consuming trans fats daily, in dangerous amounts.
American manufacturers are allowed to label products as “trans fat free” if there is less than a half gram of trans fats per serving.
But how many people eat a single serving of packaged cookies? Half grams can add up fast when we overindulge.
In a study analyzing the contents of canola oil and soybean oil pulled from supermarket shelves, data showed trans fat content varied between 0.56% to 4.2%. (25) The labels on these products stated the contents were free of trans fats.
Reading labels can’t always help you avoid trans fats, but it still makes sense to check ingredient lists for hydrogenated or partially hydrogenated oils, and avoid buying products containing them.
Better yet, avoid buying processed foods altogether. Consider limiting restaurant meals in order to help cut down on the amount of trans fats you’re eating, and cook at home with fats you can trust: coconut oil, butter and olive oil.
Eating trans fats found in processed foods and vegetable oils on a regular basis is truly gambling with your health.
Summary: Trans fats cause inflammation, damage arteries, lead to metabolic imbalances, and increase the risk of developing heart disease. Trans fats are toxic, and should be eliminated from a healthy diet.