How Safe & Effective is Gingko?

Ginkgo, a perennial top-selling herbal supplement used to enhance memory function came under fire late last week as a threat to our health by the Center for Science in the Public Interest (CSPI). Citing a new study from the government’s National Toxicology Program (NTP) that found “clear evidence that the ingredient caused liver cancer in mice and thyroid cancer in rats,” the CSPI urged consumers to “avoid ginkgo in the wake of new cancer concerns.”

But just a day earlier, in a webinar led by Mark Blumenthal, the executive director of the American Botanical Council (ABC) on The Science of Herbal Medicines: What Works and Why (see my last blogpost for a summary), I learned that ginkgo extract had been shown in a meta-analysis of several “gold-standard” clinical trials to be effective in improving cognitive function in people with mild dementia. An earlier examination of 16 clinical trials in 2005 also showed that gingko was just as effective in improving mental performance  (i.e. remembering shopping lists and short term memory) in non-impaired, healthy adults.

The research findings, as explained by Blumenthal, are certainly compelling. But is the gingko extract product we buy in the U.S. carcinogenic?

The ABC, a non-profit organization whose mission is “to provide education using science-based and traditional information to promote responsible use of herbal medicine,” responded to the CPSI’s statement on Friday with a press release saying that “ginkgo extracts sold as dietary supplements in the U.S. are safe for most consumers.” It further explained that the ginkgo extract used in the government study was manufactured in Shanghai, and different from the high-quality ginkgo extracts, made in Germany, and used in published clinical trials showing safety and various beneficial activities of ginkgo. Blumenthal said;

“The NTP’s public message, and the resulting media reports, totally miss this point about the actual identity of the ginkgo extract and the high-dosage levels, and will probably cause confusion among consumers and health professionals alike.”

The volley of comments about the safety and effectiveness of gingko biloba extract reminds us how important it is to go behind the headlines if you’re considering taking an herbal supplement.

To hear Mark Blumenthal’s entire presentation, including his comments about the research behind ginkgo, visit the website of Terry Talks Nutrition, which hosted the webinar.

This recently published e-book, Herbal Remedies – Benefits of Ginkgo Leaf Extract, offers more information about this medicinal herb.