NIH Workshop Reviews Science Behind Cardiovascular Supplements

BETHESDA, Md.--The National Institutes of Health (NIH) concluded a meeting today that was held to allow an international group of alternative medicine researchers and practitioners to exchange ideas, report on current research and discuss ways to foster collaborative research on the cardiovascular effects of garlic, Ginkgo biloba, hawthorn and phytoestrogens. The workshop, titled Mechanistic Studies of Cardiovascular Effects of Botanicals, was held here Aug. 22 to 23, and was jointly sponsored by the National Heart, Lung and Blood Institute (NHLBI), the NIH Office of Dietary Supplements (ODS) and the National Center for Complementary and Alternative Medicine (NCCAM).

The goal of the workshop was to assess the current state of research on the mechanisms of action responsible for the cardiovascular effects of several dietary supplements, as well as to review evidence for those supplements' clinical efficacy. Attendees were expected to develop recommendations for future research at the conclusion of the meeting.

"A lot of the recommendations had already been pre-generated by the two meeting co-chairs," said John Cardellina, vice president of botanical science and regulatory affairs at the Council for Responsible Nutrition (CRN), who attended the meeting. "They were pretty typical kinds of things you would see--let's make sure the materials that are going into clinical studies are standardized, that their content and purity have been verified and there's an adequate supply of the same live materials to carry out through the whole study. ... There was also discussion of study design in terms of making sure the journals that publish studies require that the study authors carefully and completely describe what they actually tested." Cardellina said some studies generically name an herb without citing which species of plant, whether it was aerial or root, how it was made or what dosage was used. "The point of this recommendation is you have to be able to put this study in the context of whatever else is already known about it," Cardellina added.

The workshop was divided into three sessions. The first and second sessions covered garlic and ginkgo, and the third session covered flavonoid-containing botanicals, such as hawthorn and phytoestrogens. Some highlights from the meeting included: "Introduction and Overview of the Chemistry and Medicinal Properties of Garlic," presented by Eric Block, Ph.D., of State University of New York at Albany; "Clinical Trials: Effect of Garlic Preparations on Cardiovascular Disease and Its Risk Factors," presented by Christopher Gardner, Ph.D., of Stanford University; "Vascular Effects of Ginkgo Biloba: Pre-clinical Studies," presented by John Farquhar, M.D., of Stanford University; "Hawthorn Extract for Congestive Heart Failure: Pre-clinical and Clinical Studies," presented by Keith Aaronson, M.D., of the University of Michigan; and "Clinical Studies of the Cardiovascular Effects of Phytoestrogens," presented by Gregory Burke, M.D., M.Sc., of Wake Forest University.

"Overall, I'm happy with the outcome of the meeting because I think, largely, the studies that were discussed and the enthusiasm and interest level of the researchers who were speaking were all solid," Cardellina said. "I'm heartened to see that there is a very significant and large trial of ginkgo being done, there are two very substantial and what look to be meaningful trials of hawthorn being done--one in the United States and one in Europe. It's just good to see we're picking up more momentum in conducting clinical trials on some of these botanicals."

As of press time, there was no word as to when the scientists' recommendations from the meeting would be released to the public. More on the workshop agenda can be found online (nccam.nih.gov/news/agenda/index.htm).