Have you ever wondered how in the world those self-proclaimed "soft" chocolate chip cookies that are packed in little plastic bags deliberately placed at the check out counter of your local convenience store can stay so soft and delicious after so many months of just sitting there? While licking the remains of that third piece of fast food chicken from your finger tips, have you ever paused between bites and asked yourself what is the secret ingredient that makes this meal so finger-licking good? And lastly, when looking for something to eat in your barren refrigerator and the only item found is a stick of margarine that you bought last year, have you ever contemplated why it is that you didn’t end up in the emergency room after eating that margarine spread upon some stale crackers?
The answer to the above questions is invariably trans fatty acids (TFAs), aka partially hydrogenated vegetable oils. TFAs are semi-solid fats produced when naturally occurring vegetable oils are heated and mixed with metals and hydrogen in a process called partial hydrogenation. This process converts liquid vegetable oil into a semi-solid fat that is quite tasty as well as contributes to the prolonged shelf life of many foods. However, don’t be fooled into thinking that these fats are good for you since they are formed from the oils of vegetables. Recent data has shown that this type of fat can be quite deleterious to your cholesterol profile and its consumption can increase your risk of a heart attack. In fact, on January 1 of this year, the FDA ruled that all conventional foods and supplements must indicate the amount of TFAs on their labels.
Major sources of TFAs are fast foods (french fries, chicken nuggets, breaded fish burgers), packaged snacks (potato chips, tortilla chips, microwave popcorn), bakery treats (packaged cookies, pies, doughnuts, brownies, muffins), and margarines (vegetable shortening, hard stick, or some tub forms). Meat and dairy products do contain small amounts of naturally occurring TFAs. TFA is different than saturated, monounsaturated, and polyunsaturated fats.
Trans Fatty Acids: What’s the Worry?
Evidence has shown that TFAs are quite bad for your cholesterol. They raise LDL "bad" cholesterol, lower HDL "good" cholesterol, and increase triglyceride levels. In addition, population studies have shown that TFAs increase the risk of heart disease out of proportion to their deleterious effects on cholesterol. Therefore, they also increase the risk of heart attack through other additional effects such as increasing overall body inflammation or disrupting the ability of heart arteries to relax.
The best way to avoid the risks associated with TFA is to avoid their consumption. Now that certain packaged foods are required to list the amount of this unhealthy fat on their nutrition label, you can more carefully scrutinize what you eat. Just remember, if a food item contains less than 0.5gms of trans fatty acid, the food company is allowed to list the amount of trans fat as 0 but will list "partially hydrogenated oil" under the ingredients. Some food manufacturers have also voluntarily reduced the amount of TFA content and there is a movement to have the US fast food industry do the same, as is already the case in Denmark. Elimination of all TFA from your diet is impractical and you should enjoy what you eat. I would advise that you think about what’s in the food you are eating and consider alternative healthier choices. But, if you just have to have that order of french fries, enjoy them as much as possible and perhaps think twice the next time you order at the drive-thru.
Steven Kang, M.D., is a general cardiologist and cardiac electrophysiologist who believes that the best way to treat heart disease is to prevent it. He wrote for HealthCentral as a health professional for Heart Disease, High Blood Pressure, and High Cholesterol.