A natural therapy for menopause

MANY women bade farewell to hormone therapy after a major study found risks from taking hormones after menopause -- and far fewer benefits than once believed.

But not all.

Some women felt that, for them, the benefits outweighed the risks. Others turned to "bioidentical hormones," which are synthesized from soy and yams and are similar to the hormones the body produces. They're much more similar, for instance, than the hormones in pills such as Prempro and Premarin.

Some mainstream researchers are leery. Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women's Hospital, called the research on bioidentical hormones "very, very sparse."

"We need to be cautious about not repeating the debacle that occurred with conventional hormone therapy," said Manson, a leader in the 2002 research on standard hormone replacement therapy.

In a newsletter last September, doctors from the Mayo Clinic similarly warned that "hormones aren't safer or better just because they're labeled natural or bioidentical."

Proponents argue that bioidentical hormones won't have the dangerous side effects of oral hormones, such as Prempro, which the 2002 study found to modestly increase the risk of breast cancer, heart disease and stroke from blood clots.

Key to the approach is not just the hormones used but the way they're delivered.

The only way to get a "bioidentical" substance into the system is non-orally, chiefly through the skin via patches, creams, lotions or gels. That's because medicines taken orally don't enter the bloodstream in the same form that you take them. They pass first through the liver, where their chemical structure is altered.

Medicines taken transdermally don't pass through the liver first en route to the bloodstream, and thus aren't altered.

For example, when a woman takes oral estradiol, the hormone that declines precipitously at menopause, it is converted in the liver to estrone, a weaker hormone, said Dr. Alan M. Altman, a menopause specialist in private practice in Brookline, Mass.

By contrast, when estradiol is absorbed transdermally, it gets right into the bloodstream -- as estradiol.

Transdermally delivered estradiol appears not to increase certain cardiovascular risk factors, such as blood clotting proteins, triglycerides and C-reactive protein, as oral estradiol does, hormone specialists say.

And research suggests that oral estrogen reduces the amount of available testosterone and therefore sex drive, while transdermal does not.