The National Toxicology Program (NTP) a division of the Health and Human Services Department, published a report over a month ago detailing the results of research on mice administered Ginkgo biloba. Our initial coverage of this report included quotes from expert reviewers—as released in the report—stating the results should not be used to form risk assessment related to humans.
Further, natural products and botanical experts chimed in with their own admonitions about the research results, including comments from Steven Dentali, PhD., chief science officer for the American Herbal Products Association (AHPA) on how the ginkgo preparation used in the NTP study was not representative of ginkgo extracts marketed in the United States, noting the concentrated actives were much higher and more comparable to drug development doses. The American Botanical Council (ABC) sent NTP comments expressing concern that dosage levels used in the study were 55- to 108-times higher than what is normally ingested by consumers. "At best, what NTP can say is that significantly high doses of this particular Shanghai Chinese ginkgo extract—when added to a corn-oil base—produced cancer in the lab animals," argued Mark Blumenthal, founder and executive director of ABC.
So why then has CSPI called for FDA to ban ginkgo under the warning the herbal ingredient causes cancer in the NTP research? CSPI argued the NTP said the composition of the extract it tested falls within the range of what is sold. "It used to be the case that the only problems associated with Gingko were the unfounded and deceptive claims by manufacturers that it helped memory," said CSPI executive director Michael F. Jacobson. “Now we know these make-believe benefits are far outweighed by a real risk of cancer."
CSPI noted FDA has told a beverage maker ginkgo is no generally recognized as safe (GRAS) for use in foods and beverages. The warning letter from FDA does reference the NTP report.
Steve Mister, president and CEO of the Council for Responsible Nutrition (CRN), took issue with CSPI's tactic. “Ginkgo biloba has literally been used for thousands of years, and this attempt by CSPI to discredit this safe and beneficial dietary supplement demonstrates an irresponsible misinterpretation of both the science and the intent of the National Toxicology Program (NTP) in reviewing ginkgo," he said. "This premature evaluation from CSPI reveals an abuse of its position, a lack of understanding about the regulation of food by FDA, and presents a true disservice to consumers."
In fact, Mister highlighted FDA's response to CSPI (as publicized in the New York Daily News): "…it is not scientifically valid to conclude with certainty that dietary supplement products containing Ginkgo biloba are unsafe based solely on data from the new NTP study. In the study, rats and mice were fed amounts of Ginkgo biloba extracts (by body weight) that may be considerably greater from those which a consumer would normally ingest from a dietary supplement product containing Ginkgo biloba. In addition, there may be differences in the extract used in these studies in contrast to what is available on the market for Ginkgo biloba dietary supplements."
For some detailed criticism of the NTP findings on ginkgo, check out this article from ABC, published in a recent issue of Herbalgram, as well as AHPA's analysis of the extract used in the NTP studies. Find the NTP ginkgo report at the NTP website.