DEAR MAYO CLINIC: I’ve heard that some foods that are labeled as “trans fat-free” actually may contain harmful trans fats. Is this true?
ANSWER: Yes. Under labeling laws, a food can be labeled as “trans fat-free” or “containing no trans fat” if it has less than 0.5 grams of trans fats a serving.
This may seem like a minor issue, because the amount of trans fats is so small. But, think realistically of how small a true serving sometimes is. Do you always stop at a handful of crackers or a single cookie? If, for example, a type of crackers contains 0.4 grams of trans fats in a serving, and the package contains 10 servings, you still would be eating 4 grams of total trans fats if you eat the whole package.
Trans fats can increase your risk of cardiovascular disease. They raise your low-density lipoprotein (LDL) cholesterol levels and lower your high-density lipoprotein (HDL) cholesterol levels. For these reasons, dietary experts advise that you avoid consuming trans fats. The World Health Organization recommends limiting trans fats to less than 1 percent of your total calories. If you consume 2,000 calories a day, that means no more than 20 of those calories should come from trans fats. This translates to less than 2 grams a day, which can easily be found in a small amount of sweets or treats.
Trans fats are created when hydrogen is added to vegetable oils through a process called hydrogenation. These processed oils are used to improve the texture, shelf life and flavor stability of foods. Trans fats are common ingredients in commercial baked goods, such as crackers, cakes and cookies, and are often used to fry foods. Some vegetable shortenings and stick margarines contain trans fats.
To avoid trans fats, read the list of ingredients, and choose foods that do not contain partially hydrogenated oils. It’s also important to note that, since the U.S. Food and Drug Administration deemed partially hydrogenated oils no longer safe to be in foods, many manufacturers have switched to hydrogenated or saturated fats (e.g., palm oil). When the term hydrogenated appears on the label, it means the fat is saturated. Both trans fats and saturated fats increase the risk of heart disease. (adapted from Mayo Clinic Health Letter) — Katherine Zeratsky, R.D.N., L.D., Endocrinology/Nutrition, Mayo Clinic, Rochester, Minnesota