Lenore Greenstein: New labels help, but consumers still need to watch out for trans fats

Beware of trans fats in your diet. For the first time, the American Heart Association has made specific recommendations concerning the amount of trans-fats you should eat. The number of total grams of this "bad" type of fat consumed in a day should be negligible, according to a committee of experts in medicine and nutrition from the AHA.

As part of their strategy for reducing the risk of cardiovascular disease in the general population, the AHA recommended consuming less than 1 percent of all calories in the form of trans fats.

This is not as easy as it sounds. Trans fats are everywhere, and show up especially in prepared foods and in restaurant and fast food meals.

Why are they so prevalent? In addition to adding texture and flavor, trans fats increase the shelf life of baked goods such as cookies and crackers, as well as margarines. They create more stability in deep frying. And for the food manufacturer or restauranteur, they are inexpensive.

Trans fats are created when hydrogen is added to vegetable oil, allowing it to be solid at room temperature. They also occur naturally in smaller amounts in dairy products and meat from cows, sheep and other ruminant animals.

In an effort to help consumers identify trans fats, and after years of mounting evidence of potential harm, the U.S. Food and Drug Administration ruled that as of Jan. 1, food labels must include trans fat content information. However, trans fats remain common in prepared foods, and the new labeling can be deceiving.

Even though a food product is made with partially hydrogenated oil, the label can say there is 0 trans fat as long as the amount does not exceed 0.5 grams per serving. But people often eat more than one serving, and the total trans fat consumed in a day can add up.

In the U.S., the average person gets about 2 to 3 percent of their daily calories from artificially produced trans fats. That's about 40 to 60 calories in a typical 2,000-calorie diet. A Harvard study recommended that trans fat should be limited to less than 0.5 percent of daily calories, or about 10 calories. A gram of fat contains about 9 calories.

According to researchers at the Harvard School of Public Health and Wageningen University, removing trans fats from the industrial food supply could prevent tens of thousands of heart attacks and cardiac deaths each year in the United States.

In a review article published recently in the New England Journal of Medicine, the researchers showed evidence linking trans fats consumption to increased risk of coronary heart disease, sudden cardiac death and diabetes. They concluded that trans fats from partially hydrogenated oils have harmful effects on blood lipids, promote inflammation and cause blood-vessel abnormalities, all of which are risk factors for heart disease.

Specifically, trans fats tend to raise LDL cholesterol (the bad cholesterol), lower HDL cholesterol (the good cholesterol) as well as raise triglycerides, a type of unhealthy fat found in the blood.

They also increase Lp(a) lipoprotein, another unhealthy substance found in the blood, and reduce the particle size of LDL cholesterol, which can damage coronary arteries.

The scientists estimated that a near elimination of artificially produced trans fats would result in a 6 percent to 19 percent reduction in the 1.2 million heart attacks and deaths from coronary heart disease that occur each year in the U.S.

Premature deaths alone would drop by 30,000 to 100,000 each year, said senior researchers Walter Willett, a physician and professor of epidemiology and nutrition at the Harvard School of Public Health.

Willett said trans fats should be banned because they have no nutritional value, and their health risks are well documented.

Lenore S. Greenstein is a registered dietitian in private practice in the Naples area.