SAN DIEGO, CALIFORNIA. The standard hormone replacement therapy for menopausal women (estrogen plus medroxy progesterone acetate) has fallen out of favour since it was discovered that it is associated with an increased risk of cardiovascular disease, breast cancer, and stroke. Recent studies have, however, shown that ultra-low doses of estrogen (0.25 mg/day) may help reduce bone loss and thus prevent osteoporosis and hip fractures. It is not known whether these lower doses are still associated with a higher risk of cardiovascular disease, stroke, and breast cancer.
The finding that ultra-low doses of estrogen (estradiol) may be beneficial has rekindled the interest in certain
herbs that mimic estrogen in their action. Researchers at the University of California have developed an
accurate method for determining in vitro estrogen bioactivity of these herbs. They tested red clover
(Trifolium pretense L.), dong quai (Angelica sinensis), black cohosh (Cimicifuga
racemosa), soy, licorice (Glycyrrhiza glabra), chaste tree berry (Vitex agnus-castus L.), fo-
ti (Polygonum multiflorum), and hops (Humulus lupulus L.). They found that soy, clover,
licorice, hops and fo-ti had significant estrogen bioactivity, while chaste tree berry, black cohosh and dong
quai did not. Black cohosh, soy and chaste berry have, nevertheless, been found useful in relieving certain
menopausal symptoms. Fo-ti had the highest estrogen bioactivity at 1/300 (0.33%) of that of pure estradiol
followed by soy at 1/330, red clover at 1/400, and licorice at 1/1650. Removing a glycone group in soy
resulted in a compound with an estrogen bioactivity of 1/80 (1.25%) of that of pure estradiol. Clinical studies
are now underway to determine the actual estrogen bioactivity in women using supplements containing the
Editor's comment: The finding that as little as 0.25 mg/day of estrogen may be beneficial in preventing bone loss might, unless I am misinterpreting the results, mean that as little as 75 mg/day (0.25 x 300) of fo-ti extract may have a similar beneficial effect.