ITHACA, N.Y., July 12 (UPI) -- Cornell University experts are warning women taking soy or herbal supplements to do so with care, for they might alter their breast cancer risks.
The warning comes from Barbour Warren, a Cornell University expert affiliated with the Program on Breast Cancer and Environmental Risk Factors.
"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 Warren.
Even if some of the substances might prove to have beneficial effects, Warren said the lack of any current regulatory oversight has created an herbal supplement marketplace that "is such a mess" women should have lots of reservations in taking the supplements.
"Just because herbal medicines are 'natural' products doesn't mean they are safer than conventional medicines," he said, adding ingredients in herbal medicines might also have adverse effects and lead to health problems.
He noted researchers used to believe estrogen-like plant compounds might reduce breast cancer risk. However, recent clinical studies show women on diets high in soy experience greater breast cell multiplication. That, he said, could be a preliminary step in cancer formation.
