Does Saccharin Cause Cancer?

Rumors abound about the link between saccharin and cancer. But the prevailing opinion among experts today is that there is no link between saccharin and cancer in humans. Beginning in the 1970s, multiple studies found that saccharin may cause bladder cancer in rats. After many years of examining those studies, the U.S. National Toxicology Program has decided to remove saccharin from its list of substances thought to be potentially carcinogenic.

History

• Saccharin was discovered in 1879. Throughout both world wars, people relied on saccharin during times of food shortages and rationing. In 1958, Congress gave the Food and Drug Administration (FDA) the power to ensure the safety of food additives. Because saccharin had been in use for many years, the FDA did not begin to study it until the 1970s.

Origin of the Controversy

• A 1977 Canadian study convinced the FDA that there was a link between saccharin and bladder cancer in rats. The FDA proposed a ban on saccharin that would have classified saccharin as an over-the-counter drug, severely limiting its sales. Because of the popularity of saccharin, Congress did not approve the FDA ban. Instead, it mandated that saccharin undergo more safety studies. Also, Congress placed a moratorium on any saccharin bans until the safety studies had been completed. The moratorium has been renewed several times since then.

Congressional Actions

• Congress also required that the labels of products containing saccharin state the following: "Use of this product may be hazardous to your health. This product contains saccharin, which has been determined to cause cancer in laboratory animals." At the time, Congress thought the label was important because of the studies that had shown there was a clear link between saccharin and bladder cancer in rats. But today, the National Cancer Institute (NCI) says that those studies only proved that saccharin causes bladder cancer in rats. The NCI says that humans lack the particular mechanism found in rats that allows saccharin to cause bladder cancer.

The Delisting of Saccharin

• Up until 2000, saccharin was listed as "reasonably anticipated to be a human carcinogen" by the U.S. National Toxicology Program. But because humans lack the relevant mechanism found in rats, and because saccharin has never been conclusively shown to cause cancer in humans, the U.S. National Toxicology Program removed saccharin from its list. Following the delisting, a 2000 law repealed the labeling requirements for products containing saccharine.

Current Expert Opinions

• The U.S. National Toxicology Program examined all the relevant studies and determined that saccharin has not been shown to cause cancer in humans. The FDA reports that the American Cancer Society, the American Medical Association and the American Dietetic Association all believe that saccharin is safe to use. And the National Cancer Institute says that there is no clear evidence that saccharin causes cancer in humans.