ABC responds to ginkgo article

Even by the NTP’s own language in the report, the results are not to be interpreted as being related to human health.

The New York Times (NYT) today ran an article in its weekly “Science Times” section on the subject of the National Toxicology Program’s (NTP) recent toxicology report on a Chinese ginkgo (Ginkgo biloba) leaf extract.

The Times article was written by Roni Caryn Rabin, a freelance writer who frequently contributes to the Times. The article is under “The Consumer” header, and was titled, “New Doubts About Ginkgo Biloba.”

The initial four paragraphs of the article read as follows:

“Millions of Americans take ginkgo biloba supplements to boost memory and prevent dementia. Studies have never found any solid evidence that ginkgo does any such thing, but it did not seem to be doing much harm.

“But last month, scientists released the first government toxicology study of ginkgo biloba, which found that the extract—one of the top-selling herbal supplements in the country—caused cancer in lab animals, including an excessive number of liver and thyroid cancers, as well as nasal tumors.

“The findings were somewhat surprising because ginkgo biloba has had a long and apparently benign history of human use. Although it has been associated with bleeding and cerebral hemorrhages in the elderly, there have generally been few reports of serious side effects.

“The results of the study do not confirm that ginkgo biloba is dangerous to humans, but it is disturbing that the laboratory animals all tended to suffer the same sorts of injuries, said Cynthia Rider of the National Toxicology Program and the lead scientist of the ginkgo biloba study.”

Among several experts Ms. Rabin interviewed for this article was Mark Blumenthal, founder and executive director of the American Botanical Council (ABC), and Steven Dentali, PhD, chief science officer of the American Herbal Products Association (AHPA). Both organizations are named in the article as having “sharply criticized the study, saying that the ginkgo extract used had a different chemical composition than the extract typically sold in the United States.” Dr. Dentali was also quoted as having stated that, “This says nothing about toxicity in people, or what would be a safe dose in people. It’s just a crude tool toxicologists have to determine if something is harmful. If it hurts the animals, maybe it hurts people.”

On April 18, both ABC and AHPA issued statements referring to various limitations, concerns, and criticisms of the NTP report. Both organizations had filed public comments in early 2012 with the NTP elaborating concerns in the draft NTP report that had been issued for public comment.

Of particular interest is the fact that even by the NTP’s own language in the report, the results of the report are not to be interpreted as being related to human health. According to the authors, “The actual determination of risk to humans from chemicals found to be carcinogenic in laboratory animals requires a wider analysis that extends beyond the purview of these studies.”

ABC emphasized that the Shanghai Chinese ginkgo extract used in the two-year NTP study was not consistent with clinically tested ginkgo extracts or those standards for ginkgo extract that have been published in official compendial standards, such as national pharmacopeias. AHPA also noted that the Chinese extract was not consistent with those sold in the US market.

According to ABC’s Blumenthal, “Coverage of this subject in the New York Times will presumably result in more media outlets’ picking up this story and spreading to consumers and health professionals, creating what are probably unwarranted concerns about the long-term safety of appropriately manufactured ginkgo extracts.”

In addition, added Blumenthal, the Times’ statement that “Studies have never found any solid evidence that ginkgo [provides any benefit to ‘boost memory’ and ‘prevent dementia’]” is misleading. Blumenthal noted, as he had discussed with the reporter, that there is an impressive body of clinical evidence that the use of the leading German ginkgo extract does provide cognitive benefits to persons with mild dementia, among other noted benefits for patients with age-related cognitive impairment, including increases in quality of life.



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