FAT RISKIER IN FOOD THAN PESTICIDES, SCIENTISTS CONCLUDE.

Byline: Jane E. Brody The New York Times

Americans trying to avoid cancer-causing substances in foods would benefit most from eating fewer calories and fats and more fruits and vegetables, a prestigious scientific panel concluded in a report issued Thursday. The panel suggested that people should worry far less about the risk of cancer from pesticide residues and food additives.

In a finding that is sure to appeal to anyone tired of washing vegetables in detergent to remove pesticides, a 20-member panel of the National Research Council, an arm of the National Academy of Sciences, confirmed that there were many natural and synthetic cancer-causing chemicals in foods, but it said their importance as cancer-causing agents was minimal compared with the overconsumption of calories and fat.

The report, "Carcinogens and Anticarcinogens in the Human Diet," based on an exhaustive review of scientific reports and other relevant information, said that about a third of the 1.35 million new cancer cases in the nation each year could be traced to diet, but probably not to natural or synthetic chemicals in significant numbers.

"The great majority of individual naturally occurring and synthetic food chemicals are present in the human diet at levels so low," the report said, "that they are unlikely to pose an appreciable cancer risk."

Food scientists and food-industry representatives applauded the report.

Dr. Joyce A. Nettleton of the Institute of Food Technologists, most of whose members work in industry, said: "No responsible scientist in the food system would deny there are substances in the food supply that in theory could be nasty if consumed in excessive amounts, but bodies aren't piling up because of lethal substances in food. Diet-related health conditions are related to our overall habits, not to specific food chemicals present in minuscule amounts."

Timothy Willard, a spokesman for the National Food Processors Association in Washington, said the report is "in harmony with what the industry and scientists have said for years about food and health: that consumer and public-health attention should focus on the real risks, rather than trivial and mostly hypothetical risks posed by synthetic or natural carcinogens."

In another segment of the food industry, Robert Scowcroft, executive director of the Organic Farming Research Foundation in Santa Cruz, Calif., said that he does not expect the report to have much of an impact on organic foods, grown without pesticides. He said that "what motivates people to buy organic are not just food safety issues but a desire for fresh foods and taste and to protect the environment and farm workers" from pesticides.

Al Meyerhoff, senior attorney for the Natural Resources Defense Council, said that even though chemical carcinogens in foods are much less significant than tobacco, alcohol and obesity as causes of cancer, "they can still cause thousands of cancers in consumers, and they should be avoided wherever possible."

The research council committee not only assessed the importance of the overall diet and carcinogenic chemicals, it also concluded that if any chemicals are important to human cancers, then the naturally occurring carcinogens, far outnumbering the synthetic ones, probably contribute more to cancer risk.

Meyerhoff, reacting to this finding, said little can be done about natural carcinogens, but "the more than 100 known man-made carcinogens in foods are avoidable and involuntary exposures."

About 6,000 chemicals, both synthetic and natural, are deliberately or inadvertently added to foods. Hundreds of thousands - perhaps a million - chemicals are naturally present in foods. Coffee aroma alone consists of about 1,000 different chemicals.

Relatively few chemicals that occur naturally in foods have been tested for their cancer-causing potential, the committee pointed out, adding that natural food substances are not tested and regulated as are chemicals like pesticides and preservatives.

Still, the committee, led by Dr. Ronald Estabrook, a biochemist at the University of Texas Southwestern Medical Center in Dallas, cited examples of several natural carcinogens that are widely consumed in ordinary foods.

One is caffeine, most prominent by far in coffee but also found in notable amounts in apples, lettuce, peaches, pears, potatoes, tomatoes and citrus fruits. Caffeine causes cancer in laboratory animals, but its role, if any, in human cancer is unknown. Despite many studies exploring the relationship of coffee to cancer in people, no link has been established.

"While some chemicals in the diet do have the ability to cause cancer, they appear to be a threat only when they are present in foods that form an unusually large part of the diet," Estabrook said.