SACCHARIN STAYS ON WARNING LIST.

Byline: Sheryl Gay Stolberg The New York Times

The artificial sweetener saccharin, which for 20 years has been dogged by suspicion that it causes cancer, was denied the scientific equivalent of parole Friday when a board of independent experts recommended that it remain on the government's list of suspected carcinogens.

The vote was close, 4-3, and the outcome a surprise. Most scientists had expected the panel to decide that saccharin, perhaps the most studied food additive ever, should become the first substance ever to be struck from the carcinogen roster.

That now appears unlikely. The panel's advice is not binding, but it carries great weight with the National Toxicology Program, the branch of the National Institutes of Health that keeps the list.

``The closeness of the vote indicates the complexity of the issue, and the large body of scientific studies that can be looked at in different ways,'' said Michael Jacobson, executive director of the Center for Science in the Public Interest, which had pressed for saccharin to remain on the list.

The toxicology program's own scientists, having reviewed 14 animal and more than 30 human studies involving saccharin, recently concluded that it was unfairly placed on the list, in 1981, and should be removed. Although saccharin in high doses has been shown to cause bladder cancer in rats, recent research has suggested that the rat studies are not applicable to humans, whose urinary functions are different.

But the expert panel was split over contradictions in those studies and was ultimately unable to settle the 20-year-old question of whether saccharin poses a health threat to people. In the end, some panel members said, they preferred to err on the side of caution.

``De-listing is going to lay very heavy on my conscience if I'm wrong,'' one of the toxicology experts, Dr. Nicholas Hooper of the California Department of Health Services, said after the panel's two-hour discussion Friday at the toxicology program's offices in Research Triangle Park, N.C.

The result was a disappointment to the diet-food industry, which has spent years financing studies in an effort to clear saccharin's name.

The vote is unlikely to have any effect on the availability of saccharin, however. Despite the controversy surrounding it, the sweetener continues to be used in many low-calorie and sugar-free foods, including soft drinks, baked goods, jams, canned fruit, candy, dessert toppings and salad dressings.

It is also the major ingredient in Sweet 'N Low, the table-top sweetener in the familiar pink packets, which, like all foods that contain saccharin, carries a congressionally mandated warning label that might be removed should saccharin ever lose its classification as a suspected carcinogen.

Saccharin's troubles began in 1977, when a Canadian scientist first identified it as a possible carcinogen. The Food and Drug Administration proposed banning it, in keeping with a federal law that ordinarily bars from the nation's food supply all substances found to cause cancer in animal studies.

But the FDA's plan generated a public outcry. Consumers complained that they had already lost one artificial sweetener, cyclamate, taken off the market after studies had cited it as a cause of cancer. Diabetics, who rely on artificial sweeteners, argued that they needed saccharin.

In a compromise, Congress passed a law preventing the ban but requiring the warning labels. In 1981, saccharin went on the government's list, which now has 169 suspected carcinogens, saccharin among them, along with 29 known.

In recent years, scientists have tried to figure out precisely how saccharin causes cancer in rats. Much of the research has been conducted by Dr. Samuel Cohen, a pathologist at the University of Nebraska, who testified before the panel Friday.

Cohen said his research showed that when the sodium form of saccharin combines with rat urine, it creates crystal-like stones in the bladder of the animal. Those stones, in turn, lead to cellular changes that cause cancer.

But human urine is vastly different from rat urine, Cohen said, and does not react with saccharin the same way. ``We now have enough understanding to know that this is a rat-specific phenomenon,'' he said in an interview earlier this week.

Several scientists on the panel said they were unconvinced. They were especially troubled by an epidemiological study conducted in the late 1970s by the National Cancer Institute, which tracked 3,010 saccharin users and found that some subgroups, including male smokers, had a slight increase in their risk of bladder cancer.