We’ve gathered some quick answers to common questions about trans fatty acids — including some tips on how to avoid them.
Fatty acids are the building blocks of fat. For example, the fat in olive oil is made up of a variety of fatty acids (e.g. oleic, linoleic) and the fat in butter is comprised of different fatty acids (e.g., palmitic, stearic). While a very small amount of trans fats naturally occur in animal foods, the majority of trans fats in the American diet are from fast food, fried food, and commercially baked food (e.g., donuts, cookies). Trans fats are created by a process called hydrogenation; in this process, vegetable oils are hydrogenated in order to become more solid at room temperature and to give foods a longer shelf life. They are sometimes called “partially hydrogenated oils”. Trans fats have a different structure from other fatty acids and behave differently from other types of fatty acids in the body1,2
Trans fat has been associated with an increased risk for coronary heart disease. They have been shown to increase LDL (“bad”) cholesterol levels while lowering HDL (“good”) cholesterol levels — the opposite of your goals for a healthy heart.3
Overwhelming consensus is that trans fats are bad for our health. The American Heart Association recommends that we eat less than 1% of our total day’s calories from trans fats. In the diet of an average man this would be about 20 calories. Since we can consume this amount just naturally in our diet, it’s generally recommended to avoid trans fats.1,2 The 2010 US Dietary Guidelines lists trans fats as a dietary component to reduce and recommends that we keep trans fat consumption as low as possible.4
In 2006 the US FDA began requiring food manufacturers to label the amount of trans fat in foods. If a food has less than 0.5 grams of trans fat per serving, they can label it as 0 grams in the Nutrition Facts label. There is no Daily Value established for trans fats.5 One tip for avoiding trans fats is to read the ingredient list on the package and make sure that the words “partially hydrogenated” are not there.
Foods that have partially hydrogenated oils in the ingredient list typically have the most trans fat. Partially hydrogenated oils are often found in margarines, baked goods, fast food, cookies, crackers, chips, donuts, and many fried foods.
The best advice is to eat a diet made up of whole grains, vegetables, fruits, and legumes (beans and peas). Avoid, or at least reduce, your intake of foods made with partially hydrogenated oils. If you must have margarine, look for the new varieties that are labeled trans fat-free. Try using nut butters or 100% fruit spreads instead of margarine on breads. When baking, use expeller- or cold-pressed oils instead of margarine.