"It used to be the case that the only problems associated with Ginkgo were the unfounded and deceptive claims by manufacturers that it helped memory," said Michael F. Jacobson of the Center for Science in the Public Interest (CSPI). "Now we know these make-believe benefits are far outweighed by a real risk of cancer."
Researchers at the National Toxicology Program (NTP) fed the stuff to rats and mice over a two-year period and found that the rodents were more likely to develop thyroid and liver tumors than those who had managed to steer clear of the stuff.
In a shorter, three-month test, rats and mice who were given ginkgo showed early signs of tumor growth.
The supplement industry argued that the NTP used an extract of Ginkgo not used in supplements sold in the United States, but the NTP says the composition of the extract it tested falls within the range of what is sold.
Citing the NTP report, the FDA has already told one beverage maker, Stewart Brothers, Inc., that Ginkgo is not generally recognized as safe in food. It is harder for the agency to remove supplement ingredients from the market, but it may if it finds that an ingredient poses an unreasonable risk of illness or injury.
Ginkgo is found in single-ingredient supplement pills made by Natrol, GNC, Solaray, Now, and Nature's Way, as well as in multi-ingredient products such as Bayer One A Day Women's 50 Plus Advantage.
It is also used in some energy drinks, such as several varieties of Rockstar and Hansen's Energy Pro, Guru, and Steven Segal's Lightning Bolt, and in Redco Foods' Salada "Brain Boost" green tea and Yogi Tea's Ginkgo Clarity.