NIH considers how four dietary supplements might affect heart

Thursday, August 22nd 2002, 12:00 am

By: News On 6

WASHINGTON (AP) _ The National Institutes of Health is bringing together researchers this week to assess whether the dietary supplements garlic, ginkgo, hawthorn and phytoestrogens help the heart, as touted.

Understanding the possible mechanism of the biological action of widely used herbal supplements is important in designing clinical trials to see if they really help, or if they cause side effects or merely are a waste of money.

Herbs can contain numerous natural chemicals. If they do have a medicinal effect, the pills and other supplement products made from them must contain the responsible ingredient or a user won't get the hoped-for benefit, explained Dr. Michael Lin of the NIH's National Heart, Lung and Blood Institute, who organized the meeting.

There is no federal regulation of supplements to ensure that this happens.

Consider garlic. Eating one or two fresh cloves a day has been associated, in some studies, with a lower risk of heart disease. But clinical trials of less smelly garlic pills and powders have produced mixed results, with some finding no effect from garlic at all.

It turns out that some of those dietary supplements studied contained parts of garlic that are inactive, so ``no wonder it didn't work,'' Lin said.

While the effects of garlic's other, presumably active, ingredients on the heart have yet to be proved, the example shows that before designing more clinical trials of supplements, ``we want to be sure we know what we're dealing with,'' Lin said.

In addition to garlic, NIH will hear research about ginkgo, mostly touted as a memory booster, although a major study this week concluded it failed to help healthy people; hawthorn, touted for heart failure; and phytoestrogens, plant-based estrogens, mostly from soy.