As someone whose father began to show the first signs of Alzheimer’s in his 60s, I have spent hours desperately scouring research and interviewing doctors about what might help me prevent cognitive decline in myself and slow it in him. Topping the list of well-researched options are always: physical and mental exercises, a healthy diet, and lots of social interaction. Then, in the “Might help. Won’t hurt,” category has been the herb Ginkgo Biloba.
This month, the nonprofit consumer group, the Center for Science in the Public Interest, downgraded the blockbuster herb from “safe” to “avoid,” in its supplement database, and asked the Food and Drug Administration to pull it from the market, after a federal study concluded that it “caused cancers” in mice and rats. Several beverage makers, including Rockstar, have already removed it, and the FDA has issued letters to others asking them to do so.
For the two-year study, the National Toxicology Program gave rodents various doses of Ginkgo in corn oil for two years, and compared their health to those that took none. Across mice and rats of all genders, those who took the herb had more tumors – particularly of the liver, thyroid, and nose – than those who didn’t. In the male mice, those who took Ginkgo had a particularly high prevalence of aggressive liver tumors called hepatoblastomas: 6 percent of the control group got them, compared to 56 percent of the low-dose group, 72 percent of the middle-dose group, and 76 percent at high dose.
Herb and supplement trade groups have, justifiably, pointed out that the kind of Ginkgo used was not necessarily that used in the majority of U.S. products (it came from a Chinese ingredient supplier) and the doses were exponentially higher than what is used in humans. Study authors counter that similar toxicology studies (using high doses in rodents) have been used to test other popular botanicals (like ginseng and milk thistle) and found them to be totally benign. Ginkgo, “is unusual, compared to others that I have studied” lead author Cynthia Rider, PhD, recently told me. Nonetheless, she stresses that animal studies do not directly translate to humans and “immediate action” isn’t warranted.
Given the absolute dearth of effective pharmaceuticals for preventing or managing dementia, I’m not ready to write off Ginkgo yet. As the number of people with Alzheimer’s grows, herbs and supplements could play an important role.
But the study shines a light on a critical point: There is no magic pill, and contrary to popular belief, even so-called “natural” alternatives carry very real risks that must be weighed.
For now, I’m sticking with the exercise and healthy diet.
Lisa Marshall is a freelance health and medical science writer in Lyons, Colo. Connect at www.lisaannmarshall.com.
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