STUDY CITES NEW RISKS IN FAST FOOD.

Byline: Nicole Koch The Dallas Morning News

Before you take a hearty bite of that Big Mac, listen to this.

A new study released Thursday found that oxidized cholesterol - which is produced when cholesterol is heated - is more damaging to the arteries than unheated cholesterol.

OK, so you already know cholesterol is bad for you. But this research suggests that fried or processed foods, including meats, eggs and dairy products, further speed up the process of clogging arteries. And although any heating can cause the oxidizing, frying is worse than, say, boiling or baking - because frying gets food hotter and exposes it to high temperatures for a longer time.

Oxidized cholesterol is common in Western diets, especially in fast food. It's in the burger and maybe the fries you're eating today.

Researchers report in this month's ``Arteriosclerosis, Thrombosis and Vascular Biology,'' a journal of the American Heart Association, that a two-year study using rabbits showed oxidized cholesterol caused clogged arteries faster than unheated cholesterol. Experts agree that the findings are intriguing but warn against firm conclusions until testing in humans is completed.

Roger Doan of Lewisville, Texas, eats fast food every day. On this particular day, he chooses a Whopper and king-size fries from the Burger King on Industrial Boulevard near downtown.

Doan knows what he eats isn't healthy - it's just more convenient than bringing food from home. He's reminded of his convenient ways each morning, though.

``Every time I take a shower, and I'm going, jeez,'' Doan says, as he pats his belly. ``I remember when I was healthy.''

Across the street at McDonald's, Natalie Edwards and Bert Hamlin just shrug their shoulders and continue with their meal: a 2-inch pile of french fries between them, a chicken sandwich for him and a fish sandwich for her.

The fries aren't a problem, because a few years ago most major fast-food chains switched to vegetable oil, which has no cholesterol. The sandwiches are another matter.

``I don't think about cholesterol when I eat,'' Edwards tells Hamlin.

``There are bigger problems in this world than cholesterol,'' he answers.

``We're just beating our paths to the grave,'' she jokes back.

They say they'll order an angioplasty to have their arteries unclogged for dessert.

Dr. Ilonas Staprans, associate research professor at Veterans Affairs Medical Center in San Francisco, says people probably won't pay much attention to the study - but they should if they care about their health.

``It took how many years to convince people smoking was bad?'' says Staprans, one author of the study. ``This is the beginning of a new risk factor.''

The best way you can cut down on oxidized cholesterol is to eat low-cholesterol foods, Liebman says.

``There are options, but you have to think twice,'' she says. ``You can't just go for the Big Mac because that's what you've always done. You can't just pass by Burger King and follow your nose.''

Albert Chavez, marketing supervisor for McDonald's regional office, said the restaurant chain offers a variety of low-fat foods on the menu, such as the chicken sandwich, when ordered without mayo. A spokesman for Burger King was unavailable for comment. Both restaurants also have salads.

Dr. Ishwarlal Jialal, a professor of internal medicine and pathology at University of Texas Southwestern Medical Center at Dallas, says that although the findings of the study are important, it is important to remember it was performed on rabbits - not humans.

``People should listen to their doctors and eat a diet that is rich in fruits and vegetables,'' he says. ``I don't think that we should over-interpret these findings.''

One thing is sure: Cholesterol oxidizes very easily. When cooking at home, Feingold advises, be careful preparing food using heat and exposure to air. Certain types of preparation - such as using the microwave - are more likely to increase oxidation, he says.

The best advice is to eat as little cholesterol as possible. That means fewer than 300 milligrams for healthy people and fewer than 200 milligrams for those with heart problems, Feingold says.

Four ounces of extra lean ground beef pan fried to well done has 105 milligrams of cholesterol, for example. A large egg scrambled has 215 milligrams. A Big Mac has 103 milligrams of cholesterol; a Whopper with cheese has 115 milligrams.