After more than 2 decades under suspicion as a human carcinogen, saccharin--one of the most controversial food additives ever--may be exonerated by the federal government after a hearing later this week. But some prominent scientists oppose the move, arguing that the artificial sweetener is still potentially dangerous.
Saccharin came under suspicion in the 1970s when studies found it caused bladder cancer in male rats fed piles of sodium saccharin. Other animal tests and human population studies, however, turned up negative or equivocal findings. The debate became so hot that in 1977, Congress ordered the Food and Drug Administration (FDA) not to ban saccharin. But FDA still requires warnings on food, and the federal Report on Carcinogens lists saccharin as "reasonably anticipated to be a human carcinogen."
On Thursday and Friday, an advisory panel of the National Toxicology Program (NTP) meeting in Research Triangle Park, North Carolina, will consider a petition from an industry group, the Calorie Control Council, to remove saccharin from the 1999 carcinogens report. In a draft document recommending delisting, NTP points to new research suggesting that male rats fed saccharin develop bladder tumors only under "rat-specific" urinary conditions not likely to occur in humans, including high pH and the formation of crystals.
But NTP's arguments are "flawed," claims a 24 October letter from the Center for Science in the Public Interest in Washington, D.C. Among the eight signers are epidemiologist Devra Davis of the World Resources Institute in Washington, D.C., and pathologist Emmanuel Farber, of Jefferson Medical College in Philadelphia, chair of a 1978 National Academy of Sciences panel that found saccharin to be a weak carcinogen. The letter notes, for example, that other cancers increased in some rodent studies; and that certain subgroups of people using artificial sweeteners, such as nonsmoking women, did appear to have a bladder cancer risk. "My concern is children," says Farber, since they could consume "lots of saccharin" in soft drinks. "That makes me nervous."
They aren't the only researchers with doubts: According to NTP's William Jameson, the votes on two NTP scientific committees that recommended delisting saccharin were not unanimous. The NTP is expected to send a final recommendation to Health and Human Services Secretary Donna Shalala sometime next year.