Sugar substitutes.

Increased interest in controlling body weight, coupled with wide publicity about the effects on health of consuming refined sugars, have resulted in widespread use of sugar substitutes by many Canadians. Although there are clear pressures to increase the use of sugar substitutes, public attitudes towards such products are in part also conditioned by more general concerns about chemical additives in food. These concerns stem from the cancer phobia so prevalent in North America, the growing distrust of science and technology, and the expanding ability of scientists to detect and evaluate subtle or delayed effects of chemicals on health. Saccharin has been used as a sugar substitute for more than three quarters of a century, following its accidental discovery in 1879 by Constantin Fahlberg, a graduate student in Ira Remsen's laboratory at Johns Hopkins University in Baltimore, Maryland. Had Fahlberg been more fastidious in his personal habits the discovery of saccharin's sweetening powers might well have been delayed. In the course of investigations on the oxidation of toluenesulfonamide he spilled on his fingers some of a compound he was working with. He noted the sweet taste of the bread he ate with his meal that night and traced the sweetness to the chemical now known as saccharin. Saccharin's potential as a sweetening agent was quickly recognized and the substance was soon used as a substitute for sugar in candies and bakery products. Almost at once controversy arose regarding its safety; the passage of time has done little to reduce the furore. Although Theodore Roosevelt considered that "anybody who says saccharin is injurious to health is an idiot",1 during the presidency of his successor, W. Howard Taft, saccharin was banned in the United States from use in soft drinks and foods. A shortage of sugar in World War I led to its reintroduction, but it was used little until the late 1 950s, when sugar substitutes began to be used in foods designated for special diets. By 1970 the consumption of saccharin in Canada and the United States had risen to more than 2.5 million kg annually, as compared with less than 15 000 kg in 1953. In 1976 approximately 70% of the saccharin used in Canada and the United States was in so-called "diet" soft drinks, 13% was in dietetic foods and 12% was in table-top sweeteners. Given the continued controversy about its use, it is not surprising that saccharin has been extensively tested for safety. At least 13 long-term studies in rats, hamsters and mice have been conducted in such countries as Canada, Germany, Japan, the Netherlands, the United Kingdom and the United States.2 All but three were one-generation studies, none of which showed saccharin to be unsafe. However, in all three two-generation studies an increased incidence of bladder tumours was found in second-generation male rodents given large amounts of saccharin. ' In 1977, following evaluation of the results of a two-generation study on rats conducted by the health protection branch of Health and Welfare Canada,4 saccharin was banned from use in foods sold in Canada. However, it continues to be available in pharmacies, alone or in combination with cyclamates, for persons with diabetes or other reasons for restricting their intake of sugar. Although the use of large amounts of saccharin in studies with animals has been disputed by some, both the office of technology assessment (a branch of the United States Congress)5 and the United States National Academy of Sciences (NAS)' have concluded that saccharin is carcinogenic for rats, albeit with low potency. In addition to acting by itself, saccharin promotes the effects of other carcinogens in rats. It thus acts as both an initiator and a promoter of cancer. The NAS committee concluded that, although results obtained from valid studies with animals can, in principle, be extrapolated to humans, it is impossible at this time to estimate with confidence the risk to humans of saccharin consumption. The committee also noted that available reports of epidemiologic studies do not provide clear evidence to support or refute an association between bladder cancer in males and the use of saccharin. The NAS committee called attention to the increasing use of saccharin by children under 10 years of age in the United States: approximately one third of American children in this age group now regularly consume products containing saccharin. Much of the controversy surrounding regulatory decisions on saccharin use has revolved around the pur-