Saccharin has been the subject of extensive scientific research. It is one of the most studied ingredients in the food supply. Although the totality of the available research indicates saccharin is safe for human consumption, there has been controversy over its safety. The basis for the controversy rests primarily on findings of bladder tumors in some male rats fed high doses of sodium saccharin.

Considerable saccharin research, however, indicates safety at human levels of consumption. The average user of saccharin ingests less than one ounce of the artificial sweetener each year.

The scientific data supporting saccharin’s safety include the following:

Extensive research on human populations has established no association between saccharin and cancer. More than 30 human studies have been completed and indicate saccharin’s safety at human levels of consumption.

In 14 single-generation animal studies involving several species of animals, saccharin was not shown to induce cancer in any organ, even at exceptionally high dose levels.

Saccharin is not metabolized (it passes through the body unchanged) and does not react with DNA (nucleic acid present in all living cells), meaning that saccharin lacks two of the major characteristics of a classical carcinogen.

Saccharin is approved in more than 100 countries, including most recently in Canada, and has been reviewed and determined safe by the Joint Expert Committee on Food Additives (JECFA) of the World Health Organization and the Scientific Committee for Food of the European Union. Based on current research, JECFA recently doubled the ADI (acceptable daily intake) for saccharin. JECFA noted that the animal data which earlier raised questions about saccharin are not considered relevant to humans.

Controversial Rat Experiments

In summary, the case against saccharin still rests primarily on controversial high-dose rat studies in which a sensitive strain was fed the human equivalent of the sodium saccharin in hundreds of cans of diet soft drink a day for a lifetime. Even then, the tests produced bladder tumors only in some of the male rats at the highest doses. A panel of international scientists, which met at Duke University to review saccharin research, reported that “saccharin administered to the rat at high doses produces profound biochemical and physiological changes which do not occur in humans under normal patterns of use.” The panel concluded that “the appearance of tumors in rats seems to be a species- and organ-specific phenomenon for which there is at present no explanation.”

An extensive dose-response rat study, sponsored by the Calorie Control Council and conducted at the International Research and Development Corporation (IRDC), has further elucidated saccharin’s safety at human levels of use by placing the rat data and its relevance to human health in proper perspective. The Duke panel noted: “The results of the IRDC study, by defining more sharply the dose-response relationship for bladder tumor risk in the rat, support the view that the present level of exposure of humans to saccharin, through its use as a food additive, presents an insignificant cancer risk.”

Recent research further demonstrates saccharin is unlikely to cause cancer in humans. Saccharin’s effects on the rat bladder relate to the salt form (sodium saccharin), diet, urine pH and sodium levels, protein concentrations and types of proteins, and the sex, age and strain of the rats fed sodium saccharin.

Other research indicates that the bladder tumors developed by male rats fed high doses of sodium saccharin are related to very high doses of the sodium salt and not saccharin per se. Sodium ascorbate (vitamin C) and sodium citrate, found in many foods and beverages, demonstrate similar effects.

[ More about national toxicology program and review of artificial sweetener Saccharin. ]