Officials at the National Institute of Environmental Health Sciences and its subdivision, the National Toxicology Program, announced this week that the artificial sweetener saccharin would no longer appear on their list of "cancer threats."
Saccharin, which has been in use as an alternative to sugar since the early 20th century, officially assumed the "carcinogen" title in March of 1977 when a rodent study in Canada produced an excess of bladder tumors in the male animals. This finding immediately triggered the threat of the so-called "Delaney Clause," a congressionally mandated provision that requires the Food and Drug Administration to ban literally "at the drop of a rat" any synthetic food chemical shown to cause cancer when ingested by laboratory animals.
When millions of weight-conscious Americans got the word that their only available low-calorie sweetener was going to be banned (cyclamates had been banned in 1970 for similar reasons), they were outraged and immediately bought up almost every little pink packet in the land. Congress responded to this outrage by protecting saccharin from the Delaney Clause, by allowing it back on the market with a health warning label. Saccharin's reputation was further tarnished, however, in 1981, when the National Toxicology Program, referring again to the Canadian rat study, elected to put saccharin in its "cancer causing" list formally declaring it an "anticipated human carcinogen."
There was no scientific basis for such a classification of saccharin as a human cancer hazard.
Indeed, if our policies about "carcinogens" applied to natural foods, there would be little left to eat, as chemicals that cause cancer in animals at high doses abound in nature. The American Council on Science and Health's Holiday Dinner Menu of Natural Carcinogens explains this point in vivid detail.
Further, in the case of saccharin, there was at hand clear evidence that one subgroup of Americans who consumed substantial quantities of saccharin diabetics had no evidence of any unusual cancer patterns attributable to the use of that artificial sweetener.
Yet activist groups like the Center for the Science in the Public Interest and Dr. Sidney Wolfe's Public Citizen are still promoting the notion that anything that causes cancer at high doses in lab animals will therefore cause cancer in humans even at low doses. Dr. Wolfe told Reuters Health this week: "There are a number of animal studies showing that saccharin causes cancer, and that alone should be enough to keep it on the list.''
Alas, saccharin kept that unfortunate label "carcinogen" for over 20 years. Then this week, the sweet news: the National Toxicology Program delisted saccharin as a cancer threat.
In reflecting on the broader "carcinogen" issue, however, one finds the essence to be particularly sour and unscientific. Saccharin should never have been listed as a carcinogen in the first place. The Delaney Clause, which assumes that a mouse is a little man, is misguided. Government lists of hypothetical "cancer risks" do not promote public health indeed, they divert attention from the known causes of human cancer. Even worse, the government list of "carcinogens" which includes the life-saving drug tamoxifen completely confuses people about the critical issue of benefit and risk. Yes, tamoxifen does slightly increase the risk of uterine cancer, but it also significantly reduces breast cancer risk. On balance it is supporting, not threatening, health.
There is no evidence that food additives like saccharin pose a human cancer risk nor is there any known risk from trace levels of the myriad naturally occurring animal carcinogens in our diet. The real preventable causes of cancer include cigarette smoking, alcohol abuse (particularly in conjunction with smoking), overexposure to sunlight, promiscuous unprotected sex (a risk factor for cervical cancer), high-dose exposure to radiation, occupational (high-level of exposure to) chemicals, and some pharmaceuticals. Knowledge of these causes is derived from studies of people, not rodents. The National Toxicology Program should limit itself to predicting cancer risk in laboratory animals and let the National Cancer Institute make its own list of the real cancer risks about which humans should rightly be concerned.