Cyclamate: a reappraisal.

Cyclamate: A reappraisal

Cyclamate, an artificial sweetener that has been banned in the United States since 1970 due to suspicions that it causes cancer, may speed up cancer development in the presence of other, carcinogenic substances--but it does not by itself start the process, a National Research Council committee announced this week.

Acting at the request of the U.S. Food and Drug Administration, the committee spent more than a year reviewing all existing studies on cyclamates and cancer. The committee concludes that, in animals and cell cultures at least, cyclamate can act with carcinogenic substances to increase the number of tumors formed or to speed up tumor development. But "there is little likelihood,' the committee says, that cyclamate damages the DNA in cell genes, thereby causing cancer. It's not clear, the committee adds, how study results can be interpreted to predict cyclamate's possible health effects on humans.

Cyclamates were banned after researchers in the late 1960s concluded that cyclamate/saccharin mixtures--used mostly to sweeten diet soft drinks-- caused cancer in rats; some scientists have argued ever since that saccharin, and not cyclamate, was the carcinogen. But committee head Richard J. Havel of the University of California, San Francisco, School of Medicine told SCIENCE NEWS that the committee's findings should not be used to draw conclusions about the health effects of saccharin, which in 1978 was deemed a weak carcinogen by the National Research Council, an arm of the National Academy of Sciences.

Epidemiologic studies of human consumption of the cyclamate/saccharin mixture concentrated on bladder cancer, the committee says, and did not show a "clear increase in risk in most categories of users.' However, the committee calls for more epidemiologic research on the link between cyclamates and this and other types of cancer. Also, animal data indicating that high doses of cyclamate may cause testicle shrinkage should be considered in any overall assessment of cyclamate for widespread use, the committee says.