CSPI Downgrades Safety Rating of Common Supplement Ingredient
April 18, 2013
Consumers should avoid Ginkgo biloba, a common ingredient in dietary supplements, herbal teas, and some energy drinks, based on a new study from the government's National Toxicology Program that found "clear evidence" that the ingredient caused liver cancer in mice and "some evidence" that ginkgo caused thyroid cancer in rats. That is the advice of the Center for Science in the Public Interest, which today downgraded ginkgo from "safe" to "avoid" in its Chemical Cuisine guide to food additives.
"Ginkgo has been used in recent years to let companies pretend that supplements or energy drinks with it confer some sort of benefit for memory or concentration," said CSPI executive director Michael F. Jacobson. "The evidence for those claims has been dubious, at best. The pretend benefits are now outweighed by the real risk of harm."
Ginkgo is often sold as a supplement on its own by companies such as NatureMade, Nature's Bounty, GNC, and other companies, or as one of several ingredients in supplements marketed as memory aids. It is or has been used in energy drinks such as Rockstar, Crunk, Hansen's Energy Pro, Guru, and Steven Seagal's Lightning Bolt. The Food and Drug Administration has sent warning labels to several drink companies, including Rockstar, stating that ginkgo is not generally recognized as safe, or GRAS, for use in food, though it is legal as an herbal supplement.
Researchers at the NTP gave male and female rats dosages of Ginkgo biloba extract five times a week for two years. The NTP is an interagency program connected to the Department of Health and Human Services and the National Institutes of Health. It is headquartered at the National Institute of Environmental Health Sciences in Research Triangle Park, NC.
"We conclude that Ginkgo biloba extract caused cancers of the thyroid gland in male and female rats and male mice and cancers of the liver in male and female mice," the researchers stated.