WASHINGTON (AP) - Consider it a possible additional reason to eat a lowfat diet.

A draft report from the Environmental Protection Agency suggests the cancer risk from dioxins may be greater than previously thought, but only among people who eat lots of fat.

That may sound scary but even if it's true, these long-controversial chemicals still would play a very small role in anyone's individual risk, say cancer experts.

Eating a lowfat diet with lots of fruits and vegetables, regular exercise and not smoking are the best recommendations for preventing cancer and preventing heart disease, the nation's No. 1 killer.

"An ordinary person should base their health decisions on the known major (risk) factors," says Dr. Michael Thun of the American Cancer Society. Worry about dioxins "shouldn't be one of them."

At the same time, "the kind of diet that is healthy for your heart ... is also healthy as far as protecting you from dioxin," said Dr. Gina Solomon, a physician with the Natural Resources Defense Council.

The health effects of dioxins, toxic compounds produced from combustion and certain manufacturing processes, have been controversial for decades. While very high doses sickened laboratory animals, the health effects in people have remained uncertain.

But studies have found that people worldwide have at least some dioxin in their bodies. Dioxin is released into the air and water and works its way into animals and fish, accumulating in fatty tissue. Eventually people eat it.

The concern is over cumulative lifetime exposure, not eating a single food.

In recent years, the EPA has imposed tougher regulations on many dioxin emitters. As a result, dioxin emissions have been reduced by about 80 percent since the 1980s, according to the agency.

The EPA began reviewing the health issue in 1991. Draft conclusions say a small segment of the population who eat lots of fatty foods may have a cancer risk as high as 1 in 100 from dioxin.

The draft does "show that the health risks associated with dioxin are greater than previously suspected," EPA Administrator Carol Browner said Wednesday.

But she stressed the draft report needs additional scientific review.

"We do enjoy one of the safest food supplies in the world," Browner added. "It's important to understand where dioxin is found. It tends to accumulate in fat. So a low-fat diet for any number of reasons continues to be advisable."

As dioxin in the environment dropped, it also dropped in the food supply, said Dr. Susan Alpert of the Food and Drug Administration, which has tested foods after dioxin pollution scares.

Last summer, the FDA stopped some Belgian food imports because of dioxin contamination, and in 1997 it stopped shipments of some poultry and catfish fed dioxin-contaminated feed.

But even in pollution cases, scientists find minute amounts - so small they're measured in parts per trillion.

Many scientists had thought dioxins were turning out to be less hazardous than initially feared, "so the EPA's report represents a real reversal in that opinion and it's really important to see what data they have," said the cancer society's Thun.

A higher risk might urge tougher pollution-control standards without meaning people should worry about dioxin at the dinner table, he said. "People have trouble separating issues that are important for a regulatory agency from issues important for individual life decisions."

Alpert agreed "it's premature" to offer diet recommendations. "The best thing we can say ... is to eat a varied diet," she said.

Copyright 2000 The Associated Press. All rights reserved.