Women's Heart Advisor July 2010 Issue

Trans Fats: The Enemies Of a Healthy Heart

Here’s why you need to eliminate them from your diet.

By now, most of us know that saturated fats are bad for the heart. To preserve our heart health, we’ve been told to substitute fatty cuts of meat and whole-fat dairy products with lean meats, fish and low-fat dairy.

But an even greater threat lurks in our diets, and that’s trans fats. Although trans fats occur naturally in small amounts in some meat and dairy products, the primary sources are fried foods, baked goods, desserts and candies.

"To avoid trans fats, you need to read labels on store-bought foods and be aware that some foods without labels—fried foods and desserts in restaurants, for example—may contain these dangerous fats," says Cleveland Clinic dietitian Melissa Ohlson, MS, RD, LD.

Trans fats are made by adding hydrogen to oil and heating the product to a very high temperature. The result—a partially hydrogenated oil—is a product that is solid at room temperature and has a long shelf life and a wonderful, creamy mouthfeel. Oleo and shortening are the purest forms of partially hydrogenated oil.

Trans fats increase levels of "bad" LDL cholesterol and its less-familiar-but-more-dangerous-form, very dense LDL (VLDL). VLDL gets inside the lining of the arteries, where it creates havoc by increasing inflammation, promoting clots and preventing the normal healing response—all of which can lead to insulin resistance, diabetes and heart attack. It also lowers levels of "good" HDL, the form of cholesterol that helps prevent heart attack.

How to spot trans fats

Food labels must list trans fats. "The key terms are ‘partially hydrogenated oil’ and ‘shortening.’ Some labels may say ‘oil blend,’" Ohlson explains.

In response to consumer demand for healthier foods, many products are now being reformulated to eliminate trans fats. Tub margarine, for example, may be trans fat-free; stick margarine is not. The change in formulation changes the properties of these products, so they are not always interchangeable in cooking and baking.

A food that claims to be trans fat-free may contain, by law, up to a half- gram of trans fat per serving. How much trans fat you eat, however, depends on the serving size. "If you eat the equivalent of two to three servings, you will consume a significant amount of trans fat," says Ohlson.

Avoiding baked goods—bakery-made or boxed—as well as crackers and other snack foods will likely eliminate most trans fats from your diet. However, you’ll still find these fats in unlikely places.

"Trans fats are hidden still in snack bars, condiments, icing and other not-so-obvious sources, and are present in many fried foods," says Ohlson.

In your kitchen

If you buy baked goods, read the label and check the serving size. The lower "partially hydrogenated oil" or "shortening" appears in the list of ingredients, the less it contains.

Better yet, bake your own, and eliminate trans fats entirely.

"I like to substitute part of the fat in the recipe with a healthier choice. In muffins and cakes, I use liquid canola, yogurt, a little of both, or applesauce or prunes. It may take some experimentation to find the right ingredients for your favorite recipes," says Ohlson.

"When baking cookies, I use butter, which has saturated fat, but no trans fats. Is the change to saturated fat from trans fat healthy? No. Is it a healthier choice? Yes. Still, we should eat saturated fats sparingly," she says.

The ultimate message is that you need to know what you are putting in your mouth. "We don’t know how much trans fat will hurt you. The problem is not the occasional piece of birthday cake. It’s the overall food choices you make," Ohlson says.