The use of artificial sweeteners is controversial even though they all appear safe and have been part of many peoples' diets for decades. One of the oldest is saccharin and it has an interesting history.
Saccharin was discovered in 1879 and was used early in the 20th century as a sugar replacement for diabetics. Saccharin isn't as popular as it once was, but it's still available as a powdered sweeter -- it's 200 to 700 times sweeter than table sugar so very little of it is needed..
Saccharin has a long history of safe use by humans. However, research findings raised a concern about cancer. These findings resulted in the banning of saccharin in Canada and labeling regulations in the United States.
But We're Not Rats -- Why Was Saccharin Labeled as a Cancer Causer?
In the 1970s, some lab research studies indicated that large amounts of saccharin caused bladder tumors in male rats. Those findings led to a Food and Drug Administration decision to ban the sweetener, but instead, Congress passed legislation that required all products made with saccharin to carry this warning label:
"Use of this product may be hazardous to your health. This product contains saccharin which has been determined to cause cancer in laboratory animals."
Researchers wanted to learn more about how saccharin might cause the cancer. But what they found was that the mechanism responsible for bladder tumor formation in the male rats was not relative to human biology -- the male rats synthesize a certain protein that's not found in the human body.
Since there was no reason to believe saccharin would cause cancer in people, it was removed from the list of substances that cause cancer in humans, and the law requiring the warning label was repealed. Products sold in the United States that contain saccharin are no longer required to carry warning labels.
Still Sold as a Sweetener
Saccharin may have been exonerated as a cancer-causing agent, but it's not used too often today -- mostly because newer sweeteners like aspartame and sucralose don't have the strong bitter aftertaste.
Sweet'N Low powder is available in most grocery stores, and it's found as an ingredient in a few foods. A diet soda called TaB is still sweetened with saccharin, but it also contains aspartame.
Other No-Calorie Sweeteners
Academy of Nutrition and Dietetics. "Position of the Academy of Nutrition and Dietetics: use of nutritive and nonnutritive sweeteners." J Am Diet Assoc. 2004 Feb;104(2):255-75.
National Cancer Institute. "Artificial Sweeteners and Cancer: Questions and Answers." Updated October 2006.
US Food and Drug Administration. "Artificial Sweeteners: No Calories ... Sweet!" July 2006.