A National Academy of Sciences committee yesterday told the government that the bulk of scientific evidence now suggests the artificial sweetener cyclamate does not, by itself, appear to cause cancer.
The report represents a reversal of an earlier academy report that led the government to ban the use of the sweetener in 1970. But it stops far short of giving cyclamate a clean bill of health.
Instead, the review says that new animal studies raise unresolved questions about the role of cyclamate in helping to start or speed the action of other known carcinogens and its relevance to health.
In addition, the 12-member academy committee cautioned that even if cyclamate is not thought to cause cancer, there are other "adverse effects," including possible reproductive and genetic effects in animals, that need to be taken into account before the sweetener can be used widely by humans.
Reaction to the new report, requested by the Food and Drug Administration in late 1983 to help resolve the longstanding debate over cyclamate's cancer-causing potential, varied widely yesterday, with industry arguing that the study supported the safety of cyclamate and consumer critics saying that it suggested just the opposite.
But Dr. Sanford Miller, head of the FDA's Center for Food Safety and Applied Nutrition, said that the agency is not rushing toward reapproving cyclamate.
He said the new review helps to move cyclamate one step closer toward getting back on the market. But, he said, "this is going to be a long, slow process. You don't rehabilitate substances in one fell swoop . . . . If the substance was a carcinogen and the academy said so, that would be the end of the ball game. Now it allows us to move on to the next step."
"We figure that we've got at least a year's more work to do before we can make a decision," he added.
Abbott Laboratories of North Chicago petitioned the FDA in 1982 to return cyclamate to the market, saying that dozens of new studies over the past decade had reaffirmed its safety record.
Cyclamate, accidentally discovered in 1937 by a University of Illinois graduate student, was first marketed in 1949 and later was used widely, in combination with a small amount of saccharin, in diet soft drinks and other products.
Cyclamate is about 30 times sweeter than sugar, while saccharin is about 300 times sweeter. Both are stable when used in cooking and together are thought to have a better taste than either used alone. In comparison, the newest low-calorie sweetener, aspartame, which is about 200 times sweeter than sugar, is less stable and not suitable for cooking, experts say.
In the late 1960s, a scientific study found that rats fed a diet high in cyclamate, with a smaller amount of saccharin, developed more bladder cancers, and a National Academy of Sciences review concluded that cyclamate probably was responsible. The FDA sharply limited cyclamate's use in late 1969 and the agency's parent Health and Human Services Department removed it from the market the following year.
In 1975, a National Cancer Institute committee found that the available evidence did not "establish the carcinogenity of cyclamate" or its byproducts. But the FDA concluded in 1980 that there still was not enough proof that the sweetener did not cause cancer. Last year, however, another review by an internal FDA Cancer Assessment Committee determined that "cyclamate is not carcinogenic."
The agency asked for an independent review. Although the academy panel yesterday supported the FDA's committee's view, it was more concerned than the panel about "suggestive" laboratory evidence that the sweetener might act as a co-carcinogen or a promoter of cancer. A co-carcinogen may boost the initial action of a true cancer-causing agent, while a promoter may speed up tumor growth that already has begun.
Officials for Abbott and the Calorie Control Council, an industry trade organization, said yesterday that the academy report should help to get cyclamate back on the market. Abbott vice president Richard Kasperson dismissed concern about cyclamate's accessory role in cancer as "pure speculation."
But Rod Leonard of the Community Nutrition Institute, a consumer group concerned about the safety of artificial sweeteners, said that the academy report "places the burden right back on Abbott to prove that cyclamate is safe."