- WASHINGTON - Several popular over-the-counter herbs, including St. John's
Wort and echinacea, could badly affect people's fertility, researchers
said on Monday.
- A study published in the journal Fertility
and Sterility suggests that high doses of echinacea, ginkgo and St. John's
wort can damage reproductive cells, can stop sperm from fertilising eggs
and might damage eggs and sperm.
- St. John's Wort is sold widely for use
in treating depression and anxiety, and has been shown in clinical tests
to help, while gingko biloba is marketed for boosting memory and can help
- Echinacea is sold to boost the immune
system to fight off colds and flu.
- The team at Loma Linda University School
of Medicine in California said St.John's Wort in particular both impaired
the ability of the sperm to penetrate the egg and seemed to cause genetic
mutations in the sperm.
- "This is a very important study
that could provide important information to patients suffering from infertility,''
Alan DeCherney, editor of Fertility and Sterility, said in a statement.
- "The growing popularity of these
herbal products means we must examine all their possible side effects.''
- The researchers did not test people taking
the herbal preparations but instead worked in the laboratory.
- They took hamster eggs, removed the zona
pellucida or outer shell-like coating, exposed them to the herbs and then
mixed in human sperm. Healthy human sperm usually can penetrate the egg,
but will not fertilise it.
- At very low concentrations there was
no effect, but at higher doses St. John's Wort prevented the sperm from
penetrating the eggs. Echinacea and gingko impaired penetration, and palmetto,
sold to help prostate problems, had no measurable effect.
- Sperm exposed to St. John's Wort for
more than a week were damaged, the researchers added.
- Tests will have to be done on people
to see if the effect carries over to humans. It will also have to be shown
that such herbs do get carried to the reproductive system when people take