Women Cautioned Against Using Herbal Supplements

[Guest guest]

Source: Cornell University

Date: 2005-07-13

URL: http://www.sciencedaily.com/releases/2005/07/050712230551.htm

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Women Cautioned Against Using Herbal Supplements

ITHACA, N.Y. -- Women who take soy or herbal supplements, such as black

cohosh, red clover and ginseng, should do so with care, says a Cornell

University expert affiliated with the Program on Breast Cancer and

Environmental Risk Factors (BCERF) at Cornell, the land-grant institution of

New York state.

" Although there is no direct evidence that any herbal medicines can increase

or decrease breast cancer risk, some herbs can have estrogen-like actions

and thus raise concern about their long-term use, " said Barbour Warren, a

research associate with BCERF and the co-author of the fact sheet " Herbal

Medicines and Breast Cancer Risk, " which is available free on BCERF's Web

site at http://envirocancer.cornell.edu/.

" Some of these substances may prove to have beneficial effects -- and, in fact,

may become part of conventional medicine in the future -- but for now, the

lack of any regulatory oversight has set up a marketplace for herbal

supplements, which is such a mess that women should have lots of

reservations in taking these supplements, " Warren said.

He points to not only a lack of well-designed clinical trials but also to a lack

of

any regulations regarding effectiveness or quality control in formulating these

supplements and says that women with a high risk of breast cancer should be

particularly cautious.

According to Warren, 23 percent of middle-aged women in the United States

use herbal medicines, often to treat premenstrual or menopausal symptoms

and premenstrual syndrome, to aid in breastfeeding or to decrease breast

cancer risk.

Warren reviewed the literature on herbal supplements and breast cancer risk

for his report, which was reviewed by two international experts in the field as

well as the five scientists on the BCERF staff.

" Just because herbal medicines are 'natural' products does not mean that

they are safer than conventional medicines, " he said. " The ingredients in

herbal medicines can also have adverse effects and lead to health problems.

Yet, there is no focused safety testing of herbal medicines or even reporting

system for adverse effects, so when people do have adverse effects, there's

no mechanism to pool that data. "

Warren said that researchers used to think that estrogen-like compounds from

plants, called phytoestrogens, could possibly block the effect of estrogen in

the body and perhaps reduce breast cancer risk. However, recent clinical

studies have shown that women on diets high in soy phytoestrogens

experience greater cell multiplication in the breast. There is concern over this

effect since it could be a preliminary step in cancer formation by leading to

the

outgrowth of latent cancer cells.

In looking at studies on the use of supplements for menopause, Warren

reports that the seven clinical trials using black cohosh were largely flawed

but might suggest some effectiveness. However, little evidence exists for

beneficial effects of red clover, and no benefit was reported for ginseng,

evening primrose oil or dong quai. In the 16 studies that looked at soy

supplements, twice as many studies reported no effect as those that reported

a beneficial effect, and although kava kava has been reported to have some

benefit, reports of serious side effects have led to it being banned for sale in

the United States and elsewhere.

For premenstrual syndrome, several studies found some benefit in about half

the women studied for evening primrose oil, but two of the best designed

studies found no effect; ginkgo biloba extract was found to have no effect,

while a beneficial response from chaste tree berry extracts was found in about

half the women studied. For menstrual pain, two clinical trials have examined

the Japanese herbal preparations toki-shakuyakusan and toki-shakuyakusan

with shakuyaku-kanzoto; neither found a beneficial effect.

" Some herbal medicines show promise for the treatment of problems with

menstruation and menopause and other conditions that affect women, " said

Warren. " It is unfortunate that their quality and safety are not better

controlled.

Such an environment has set up a situation where there are potentially many

accidents waiting to happen. "

However, he said, if women choose to use herbal medicines, they should do

so cautiously because the quality of these medicines varies, and the safety,

especially with long-term use, is uncertain. He said that women should

choose only high-quality products from reputable sources and to be sure to

inform their health-care providers about their herbal medication use, because

many herbal supplements can interact with other treatments.

The mission of the Cornell Program on Breast Cancer and Environmental

Risk Factors is to lower the risk and incidence of cancer by promoting

methods of sound decision-making at personal and public levels. Its staff of

scientists and educators translate basic research into forms that can be used

by the public, medical professionals, educators, activists, other scientists,

the

regulatory community and policy makers. The program offers more than 50

fact sheets on topics related to breast cancer risk, a free newsletter and

numerous other resources. For more information, see BCERF's Web site, call

or e-mail breastcancer@....