Scientists Urge Better Research
and Accreditation of BotanicalsThis section is compiled by Frank M. Painter, D.C.
Send all comments or additions to: Frankp@chiro.org
From The October 2002 Issue of Natural Foods Merchandiser
German MunozAlternative medicine researchers meeting in Washington, D.C., Aug. 22-23, recommended independent certification and standardization of botanical products—by government or an independent organization—to ensure that consumers get what they pay for. The need for accreditation and closer scrutiny of botanical content "is very high, if not first" among recommendations issued by the scientists, said conference Co-chairman Eric Block of the State University of New York at Albany.
Sponsored by the National Heart, Lung and Blood Institute, the Office of Dietary Supplements and the National Center for Complementary and Alternative Medicine—all agencies of the National Institutes of Health—the conference drew scientists from around the world to review the latest scientific data on four botanicals in particular—garlic, gingko, hawthorn and phytoestrogens. Scientists focused on possible mechanisms of action, clinical evidence of effectiveness and safety of these botanicals.
In another key recommendation, the scientists called for more and better-designed studies to determine whether commercial formulations of botanicals provide the health benefits manufacturers claim and some studies suggest. "Botanicals are widely used, but we really don't know how they work, if they work, what's in the commercial preparations or if they are safe," said Michael C. Lin, NHLBI coordinator.
Clinical researchers should try different doses to measure more accurately the potential for overdose, conference participants said. The vast majority of studies rely on single-dose tests. This is a critical area of research given that many consumers believe "more is better" when it comes to supplement use, Block said.
Moreover, studies should be longer in duration, include more subjects and have better end-point measurements. Scientists also called for more multinational clinical trials to test botanical effectiveness across cultures, such as comparing gingko use in Asia and Western populations.
Researchers also were urged to pay closer attention to botanicals' possible interactions with conventional drug therapies. Some speakers warned supplements should not replace medicines. "In drugs, we need evidence to show benefits beyond adverse effects," said Curt D. Furberg, co-chair of Wake Forest University Health Sciences Center. "In many areas, there are questions regarding botanicals." However, he had no objection to the use of botanicals to complement drug therapy.
Looking at the reported benefits of botanicals, scientists pointed out:
Allicin in garlic may lower total cholesterol, LDL cholesterol and triglycerides, while increasing HDL cholesterol.
Flavonoid glycosides, proanthocyanides and terpenoids in ginkgo may function as antioxidants.
Flavonoids in hawthorn may have antioxidant properties and may dilate blood vessels, aid the heart muscle and prevent heart arrhythmia.
Polyphenols in red wine act as antioxidants.
Phytoestrogens in soy may lower fats in the blood and thus lower the risk of heart disease, and may moderately inhibit hardening of the arteries. These benefits derive only from food, not from pills, cautioned Thomas B. Clarkson of Wake Forest School of Medicine. There is preliminary data suggesting soy may be complementary to hormone replacement therapy and may protect against certain types of cancer, osteoporosis and menopause symptoms, but more research is needed, he said.
Conference attendees cautioned, however, that a closer examination of the overall scientific literature reveals shortcomings that might undermine health claims. To illustrate, Christopher Gardner of Stanford University reported that many studies of garlic relied on dried, powder preparations, were too small and too brief, and did not use adequate dosage. Results, therefore, "are not adequate to answer important questions about the potential cardiovascular benefits of garlic," he said.
Similarly, studies on ginkgo and hawthorn have been too small and brief to provide definitive conclusions regarding benefits, said Jeff D. Williamson of Wake Forest University School of Medicine and Keith Aaronson of the University of Michigan Medical Center. Both institutions are planning better-designed studies.
Of related significance, researchers from Williams College and Southwestern Vermont Medical Center reported in the Aug. 21 Journal of the American Medical Association that ginkgo did not aid memory or cognitive function in healthy adults (see story on page 5.) In rebuttal, the National Nutritional Foods Association said several studies show a benefit for healthy and cognitively impaired people.
That same week, Dutch researchers from Erasmus MC-Daniel den Hoen Cancer Research reported in the Journal of the National Cancer Institute that St. John's wort interferes with the metabolism of the chemotherapy drug irinotecan, possibly affecting its efficacy.
Further recommendations by scientists at the conference included:
Medical journals need tougher standards for publication of botanical studies, such as clearly defining the type of supplement used.
Scheduling of regular international scientific meetings to track the progress of botanical research.
More research studies on additional beneficial compounds.
More research to determine the bioavailability of botanical substances.
Greater cooperation among various scientific disciplines.
Establishing a special section for the study of botanicals at NIH.
German Munoz is associate editor of the Washington, D.C.-based Food Nutrition Health News Service.
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