Trans fats and cis fats are both types of unsaturated fats, but they have different molecular structures and properties.
Cis fats have a curved shape in their molecular structure, which causes them to have a lower melting point and be more fluid at room temperature. Cis fats are abundant in vegetable oils such as olive oil, canola oil, and peanut oil.
Trans fats, on the other hand, have a straighter molecular structure due to the way the carbon atoms are arranged. This makes them more solid at room temperature and gives them a higher melting point. Trans fats can be found in some processed foods, such as partially hydrogenated oils, margarine, baked goods, and fried foods.
How are trans fats created and what foods are they distributed in?
Partially hydrogenated oils (PHOs) were first introduced to food industries in the early 20th century to replace expensive natural fats, such as butter, lard, tallow, and vegetable fats, such as cocoa butter. Hydrogen turns the double bonds in vegetable oils into single bonds with the help of catalyst, giving the fats a semi-solid or solid appearance at room temperature. Because of its longer shelf life and lower cost, partially hydrogenated oils are very popular in food industry. However, hydrogen turns some of the cis fats into trans fats in this process. Recent studies have shown that trans fats are metabolized slowly and are linked to atherosclerosis and heart disease.
A few trans fats are found in ruminant fats and dairy products. This is because microorganisms in cattle or sheep stomach convert vegetable oils into trans unsaturated fatty acids which are absorbed and used to synthesize fats.
In addition, vegetable oils tend to produce trans fats at about 200 degrees. For example, trans fats can be found in fried foods and refined vegetable oils. The higher frying temperature and the longer frying time, the more trans fats are produced.
Health risks of trans fats
Excessive consumption of trans fats increases low-density lipoprotein cholesterol (bad) and decreases the high-density lipoprotein cholesterol (good) , rising the risk of heart disease.
Numerous studies have confirmed that trans fats contribute to diabetes. They reduce the sensitivity of insulin receptors to make insulin resistance.
Trans fats are not easily decomposed by body and accumulate in the abdomen to cause obesity. They also increase the risk of cancer. If individuals have high levels of trans fatty acids in their blood, it can increase their risk of Alzheimer's disease by 50 to 75 percent.
They have been identified as a health hazard by the World Health Organization that launched a plan to replace trans fats on May 14, 2018. It plans to phase out industrial trans fats from the global food supply and eliminate them completely by 2023.