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donut-eater donut-eater donut-eater
(Staff photos Rose Lincoln/Harvard News Office)

Fatty foods feed heart attacks, researchers say

Doughnuts are dandy in Denmark, but a heart attack in the U.S.

By William J. Cromie
Harvard News Office

Hold the french fries, doughnuts, and cookies, and save as many as 228,000 heart attacks and deaths from heart disease. That's the message from a team of researchers at the Harvard School of Public Health and Wageningen University in the Netherlands.

"Given the 1.2 million annual [heart attacks] and deaths from coronary heart disease in the United States, near-elimination of industrially produced trans fats might avert between 72,000 and 228,000 coronary heart events each year," the researchers report. Trans fats are also thought to play a role in unexplained sudden deaths and diabetes.

The major sources of trans fats include deep-fried fast foods, bakery products, packaged snack foods, margarines, and crackers. French fries, breaded fish burgers, breaded chicken nuggets, Danish pastries, pies, doughnuts, and cookies are the big offenders. Hamburgers, steaks, lamb chops, and dairy products contain only small amounts of natural trans fats so they don't make the list of "worsts." "The presence of beneficial factors in dairy and these meats may balance the effects of the smaller amount of trans fats they contain," according to Dariush Mozaffarian, lead author of the report that appears in the April 13 issue of the New England Journal of Medicine.

The article goes on to say that, "on a per-calorie basis, trans fats appear to increase the risk of coronary heart disease more than any other [nutrient], conferring a substantially increased risk at low levels of consumption (1 to 3 percent of total energy intake, or 20 to 60 calories)." The average consumption of trans fats in the United States is, for comparison, 2 to 3 percent of total calories eaten.

Ten to 19 percent of the coronary heart disease in the United States (120,000 to 228,000 heart attacks) could be averted by reducing the intake of trans fats, says Walter Willett, head of the research and Fredrick Stare Professor of Epidemiology and Nutrition at the Harvard School of Public Health.

What about taste?

Trans fats form when hydrogen is added to vegetable oil, a process that converts the oils into semisolid fats, which increases shelf life, adds to stability during deep-frying, and enhances the taste of baked goods and sweets. According to the evidence that Mozaffarian, Willett, and their colleagues gathered from studies in the United States and Europe, the "adverse health effects of trans-fatty acids are far stronger on average than those of food contaminants or pesticide residues, which have in some cases received considerable attention. Furthermore, trans fats have no intrinsic health value above their calories."

The research team suggests that trans fats be reduced or eliminated from foods sold in stores, restaurants, and vending machines. Opposing arguments from food manufacturers and restaurants maintain that this would raise costs and lower taste. Recent experiences in Europe indicate that such concerns are overstated, say the researchers. They mention Denmark as a prime example. In that country, all oils and fats used in locally made or imported foods must contain less than 2 percent of industrially produced trans fats.

"This legislation essentially eliminated the use of partially hydrogenated vegetable oils in Denmark," Mozaffarian declares. When people buy french fries or chicken nuggets from fast-food restaurants in Denmark, the foods contain no trans fats, whereas the same foods in the United States have 5 to 10 grams per serving.

"In Norway, Finland, and the Netherlands, cooperative efforts between government agencies and food industries have also resulted in substantial reductions in the use and consumption of trans fat without notable increase in the cost or reduction in the quality and availability of foods," the report points out. Canada is mulling legislation to do the same thing.

Losing the fat

New York City is following the example of Denmark. The city's Department of Health has asked 20,000 restaurants and 14,000 food suppliers to get rid of partially hydrogenated oils and provide foods that are free of trans fats.

Some food makers in the United States have voluntarily reduced trans fats in their products. In addition, the Food and Drug Administration ruled that, effective last Jan. 1, labels on all foods and supplements must indicate their content of trans fats. The Department of Agriculture recommends that people limit trans fats to less than 1 percent of total calories. Such actions could provide added impetus for food manufacturers to produce more foods that are free of trans fats.

The Harvard article notes that the Food and Drug Administration has been petitioned to remove fats from its list of eatables shown to be safe by qualified experts. "Doing so," says Mozaffarian, "would effectively eliminate the consumption of industrially produced trans fats in the United States."

He and his colleagues admit that elimination of trans fats "may be challenging for restaurants and food manufacturers in the United States." But, they say, "experience in other countries indicates that such fats can be largely replaced by unsaturated fats without increasing the cost or reducing the quality or availability of food. Doctors and other health care providers should tell people how to minimize their intake of these harmful fats, and consumers should recognize their lack of nutritional benefits and their potential for harm. These steps should possibly result in substantial health benefits, such as averting thousands of heart attacks and deaths from coronary heart disease each year in the U.S."

Copyright 2007 by the President and Fellows of Harvard College