The Scoop on Trans Fat

Health experts are making progress in their war on trans fat, the saturated fat that was heaped into much of the fast-food, baked goods and spreads consumed by far too many Americans. But these unhealthful fats are still out there, though in smaller quantities, and now there may be concern about products that are replacing them.

Research has shown a disturbing link between trans fatty acids and increased risk of cardiovascular disease. A study at Harvard found that eating just 5 grams of trans fat a day could increase the risk of heart disease by 25 percent. Researchers concluded that eliminating trans fat from the American diet could prevent nearly 228,000 heart attacks.

Virtually unheard of a decade ago, trans fat became the new villain of the health-conscious world. In 2006, the U.S. Food and Drug Administration (FDA) began requiring food manufacturers to list trans fat content greater than half a gram on nutrition facts label. Restaurants are not required to list their contents, but many of them (especially large fast-food chains) are voluntarily taking out or reducing the trans fat, at least in some products.

What are trans fats? They are substances produced when hydrogen is added to vegetable oil, a process called hydrogenation. This process makes some foods tastier and keeps them fresher longer on store shelves.

Trans fats have been used extensively in making cakes, pies and cookies and as the basis of many lards, spreads and solid cooking oils. You might think yummy, but there's a down side. Trans fats raise the low-density lipoprotein (LDL) blood levels in the body. That's the bad cholesterol responsible for clogging arteries and causing strokes and heart attacks. Trans fats also reduce the level of good cholesterol (HDL) in the blood. A double whammy.

Note that unsaturated fats, which include monounsaturated and polyunsaturated fats, offer health benefits as long as they do not exceed 30 percent of your total calories. Your body uses fat as a source of energy. Fats also help absorb vitamins A, D, E and K into the bloodstream. As long as you do not consume an excessive amount, fat plays a major role in growth and development. Adding fat to your diet helps you add flavor to your food and achieve the feeling of fullness.

How much trans fat are we eating?

The Food and Drug Administration has estimated that the average American consumes the most trans fat in baked goods (40 percent), followed by animal products (21 percent), margarines (17 percent), fried potatoes (8 percent), potato chips, corn chips and popcorn (5 percent), shortening (4 percent), salad dressing (3 percent) and breakfast cereal and candy (1 percent each). The general recommendation for trans fat is to limit it to less than 1 percent of your total daily calories.

You may have the impression that the crackdown on trans fats has eliminated them from the food supply. This is not so. A 2008 study at the University of Minnesota found trans fats in many spreads, baked goods and salty snacks, including products that by law are allowed to list no trans fats but even though they have about half a gram a serving -- and we all know how unrealistic those alleged serving sizes are for many people.

How can you reduce trans fat in your diet?

Read labels carefully. When looking for saturated fat and cholesterol, select items that are 5 percent or less of the daily value (% DV) on the nutrition facts label.

Change the types of fat you buy. Make the switch from saturated and trans fat products to ones that contain unsaturated fats such as olive, canola, soybean, corn and sunflower oils.

Replace meat with fish. Consider adding fish to your diet. It is lower than meat in saturated fat. Fish contains omega-3 fatty acids which may offer protection against heart disease. But consult with your physician if you are pregnant, breastfeeding or considering serving fish (including canned tuna) to your child under 15 years old. Some fish may contain harmful levels of mercury.

Select lean meats. When buying or ordering meats, avoid fried meats and remove the skin. When dining out, ask about the cooking method used. Have them remove skin from poultry and ask for gravies, sauces and other toppings to be served on the side.

When shopping, look for the wording such as "partially hydrogenated oil" on items claiming to have zero grams of trans fat. These products most likely contain 0.5 grams or less per serving of trans fat. But beware. Those small amounts can quickly add up!

Are the replacements for trans fats okay to eat?

There has been some concern about products being used commercially to replace trans fats. In 2007 a well-publicized study in the journal Nutrition & Metabolism found problems with interesterified fats. Their manufacture involves combining solid fats such as hydrogenated soybean oil with liquid oils.

The study found that this process of interesterification may reduce good HDL cholesterol, and in addition may raise blood sugar and lower insulin (risk factors for diabetes). The food industry's International Food Information Council objected, saying that the study's design was flawed and that other studies have found interesterified fat may lower bad LDL cholesterol and seemed not to affect HDL, blood sugar or insulin.

How can you tell if a food contains interesterified fat? The only way to know for sure is if the label contains the word "interesterified," which is not mandatory. The food might or might not contain interesterified fat if the label mentions terms such as "fully hydrogenated vegetable oil," "palm oil" or "palm kernel oil," the International Food Information Council says.

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