What We Risk for Taste: Trans Fats Make Fast Foods Delicious but Dangerous

By John Fauber, Milwaukee Journal Sentinel

May 15–When heart patients come to the University of Wisconsin preventive cardiology clinic in Madison, Gail Underbakke’s job is to get a big portion of the dangerous fats they’ve been eating out of their diets.

That means alerting them to the dietary land mines lurking in the world of prepared food, such as the 6 grams of saturated fat and 8 grams of trans fat in a large order of McDonald’s french fries.

For decades, saturated fats, which occur naturally in animal products, have been linked to heart disease. But in the last decade trans fatty acids, which are concocted in commercial plants, have showed they may be even worse.

Calorie for calorie, trans fats, those industrially created fats that come from partially hydrogenated oils, may be the most harmful substances in the American diet, researchers say.

But just how bad for the heart are trans fats? And how prevalent are they?

Last month, researchers writing in the New England Journal of Medicine came up with a startling calculation buried deep in their exhaustive review of dozens of trans fat studies published over more than a decade.

Near elimination of artificially produced trans fats would avert between 72,000 and 228,000 heart attacks and deaths from coronary heart disease in the U.S. each year.

“The evidence for harm is considerable,” said lead author Dariush Mozaffarian, a cardiologist at Brigham and Women’s Hospital in Boston. “There really is little reason for having them in the food supply.”

Banning the substances, which are devoid of nutritional value, should be considered, said Mozaffarian, who also works as an instructor of medicine at Harvard Medical School.

“The wisest thing to do is to eliminate anything made in partially hydrogenated oils,” he said.

Underbakke, a registered dietitian at UW, said banning is an option, but there would be a downside to such a measure.

“Trans fats are in the food supply because we demand tasty, convenient foods,” she said.

If people want fewer trans fats in their diets, they will have to cook more of their meals at home, she said.

Trans fats — yum, yum

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 they cost less.

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.

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 over the course of a day, the total trans fat consumed can add up to a troubling amount, Mozaffarian said.

In addition, restaurants generally don’t tell customers how much trans fat is used in preparing foods. Often, those amounts can be high, he said.

“In those places, you have no idea what you’re eating,” he said. “Personally, I ask if I’m going to be eating anything that’s fried. I don’t ask the waiter. I ask the cook.”

A case in point is a recent analysis by Danish doctors of various trans fat levels found in french fries and chicken nuggets at McDonald’s and KFC outlets in the U.S. and 19 other countries.

At a McDonald’s in New York City, a combination of a large order of fries and an order of chicken nuggets contained more than 10 grams of trans fat. But in Denmark, where trans fat use has been restricted heavily, there was less than 1 gram.

“This health risk can be eliminated without noticeable effect for the consumer,” the authors concluded last month in the New England Journal of Medicine.

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

Many-edged sword

Why are trans fats considered to be so bad for cardiovascular health?

In their analysis, the Harvard researchers pointed to several mechanisms, including the ability of trans fats to raise LDL cholesterol (the bad kind), lower HDL cholesterol (the good kind) and 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.

In addition, the researchers point to recent evidence that trans fats increase inflammation in the body, which is considered to be an independent risk factor for heart disease.

There also is mixed evidence linking trans fats to an increased risk of diabetes.

Finally, trans fats adversely affect the health of the endothelium, the layer of cells that make up the inner lining of blood vessels.

All that means that a near elimination of artificially produced trans fats would result in a 6% to 19% reduction in the 1.2 million heart attacks and deaths from coronary heart disease that occur each year in the U.S., the authors said.

Premature deaths alone would drop by 30,000 to 100,000 each year, said senior author 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.

“They are clearly a metabolic poison . . .,” he said. “They are by far the largest amount of artificial chemical in the food supply, and we are not really equipped evolutionarily to handle them.”

Faults in study

However, the Harvard study is not the perfect analysis, but rather a collection of epidemiological findings and laboratory results, said Shailesh Patel, professor and chief of endocrinology at the Medical College of Wisconsin. The analysis also includes several short-term randomized trials.

For instance, is it the trans fats that are causing the health problems? Or is it something else that is common to the diets of people who eat lots of trans fats, such as high amounts of processed, low-fiber foods, asked Patel, who also is director of the lipid clinic at Froedtert Hospital.

The Harvard review article is not a clinical trial, Patel said. Although he concedes, as do the Harvard researchers, that actually giving people trans fats and observing heart disease rates over time would be unethical.

Patel also questioned the accuracy of the estimate of heart attacks and heart disease deaths attributed to trans fats, calling it speculation and “a nice intellectual exercise.”

He acknowledged that there is strong evidence that trans fat is harmful, but “right now, I don’t think it’s a major player in causing heart disease.”

Both Patel and UW’s Underbakke said the best advice for healthy living is to eat lots of fruits and vegetables, control portion size and to exercise regularly.

“If you take the trans fat out of a Chips Ahoy cookie, it doesn’t become a health food,” Underbakke said.

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Copyright (c) 2006, Milwaukee Journal Sentinel

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