Cyclamate was discovered in 1937 at the
University of Illinois by graduate student Michael Sveda. Sveda was working in the lab on the synthesis of an
antipyretic drug. He put his
cigarette down on the lab bench, and when he put it back in his mouth, he discovered the sweet taste of cyclamate. The patent for cyclamate was purchased by
DuPont and later sold to
Abbott Laboratories, which undertook the necessary studies and submitted a New Drug Application in 1950. Abbott intended to use cyclamate to mask the bitterness of certain drugs such as
antibiotics and
pentobarbital. In 1958, it was designated GRAS (
generally recognized as safe) by the United States
Food and Drug Administration. Cyclamate was marketed in tablet form for use by diabetics as an alternative tabletop sweetener, as well as in a liquid form. As cyclamate is stable to heat, it was and is marketed as suitable for use in cooking and baking. In 1966, a study reported that some intestinal bacteria could desulfonate cyclamate to produce
cyclohexylamine, a compound suspected to have some chronic toxicity in animals. Further research resulted in a 1969 study that found the common 10:1 cyclamate–saccharin mixture increased the incidence of
bladder cancer in
rats. The released study was showing that eight out of 240 rats fed a mixture of saccharin and cyclamates, at levels equivalent to humans ingesting 550 cans of diet soda per day, developed bladder tumors. Sales continued to expand, and in 1969, annual sales of cyclamate had reached $1 billion, which increased pressure from public safety watchdogs to restrict the usage of cyclamate. In October 1969,
Department of Health, Education & Welfare Secretary
Robert Finch, bypassing
Food and Drug Administration Commissioner
Herbert L. Ley, Jr., removed the GRAS designation from cyclamate and banned its use in general-purpose foods, though it remained available for restricted use in dietary products with additional labeling; in October 1970, the FDA, under a new commissioner, banned cyclamate completely from all food and drug products in the United States. Abbott Laboratories claimed that its own studies were unable to reproduce the 1969 study's results, and, in 1973, Abbott petitioned the FDA to lift the ban on cyclamate. This petition was eventually denied in 1980 by FDA Commissioner
Jere Goyan. Abbott Labs, together with the Calorie Control Council (a political
lobby representing the diet foods industry), filed a second petition in 1982. Although the FDA has stated that a review of all available evidence does not implicate cyclamate as a
carcinogen in mice or rats, cyclamate remains banned from food products in the United States. The petition is now held in
abeyance, though not actively considered. It is unclear whether this is at the request of Abbott Labs or because the petition is considered to be insufficient by the FDA. In 2000, a paper was published describing the results of a 24-year-long experiment in which 16 monkeys were fed a normal diet and 21 monkeys were fed either 100 or 500 mg/kg cyclamate per day; the higher dose corresponds to about 30 cans of a diet beverage. Two of the high-dosed monkeys and one of the lower-dosed monkeys were found to have malignant cancer, each with a different kind of cancer, and three benign tumors were found. The authors concluded that the study failed to demonstrate that cyclamate was carcinogenic because the cancers were all different, occurred at the same frequency as expected in healthy monkeys, and there was no way to link cyclamate to each of them. The substance did not show any DNA-damaging properties in DNA repair assays. == Legal status ==