NEW YORK - Adding to evidence of the potential benefits of so-called plant estrogens, a new study suggests that isoflavone supplements may help reduce menopausal bone loss.
UK researchers found that, when taken for a year, the supplements appeared to curb spinal bone loss in women between the ages of 49 and 65.
Isoflavones are compounds found in soybeans, chickpeas and other legumes that are similar to the female hormone estrogen. Because of this, researchers have been studying whether soy protein or supplements containing isoflavones might act as a sort of "natural" hormone replacement therapy.
Studies have shown that Asian women, whose traditional diet is rich in soy, have a relatively low rate of hip fracture, as well as breast cancer and heart disease. In addition, animal research has suggested that isoflavones might lessen bone loss related to waning estrogen levels.
Some studies of women, however, have found no evidence of bone benefits, and much of the research on isoflavones has involved only small groups of women followed for a relatively short time.
The new study, which followed 177 women for a year, is one of the largest and longest investigations of an isoflavone supplement to date, according to the authors. They found that compared with women randomly assigned to take a placebo, those who took a daily isoflavone tablet showed less bone loss in the lower spine.
The findings are published in the American Journal of Clinical Nutrition. Novogen Ltd., maker of the isoflavone supplement Promensil, provided the tablets and partial funding for the study.
Despite the study's positive results, it's too early to recommend isoflavone supplements for fighting bone loss, study author Dr. Sheila Bingham, of the Medical Research Council Dunn Human Nutrition Unit in Cambridge, told Reuters Health.
For one thing, long-range studies are necessary to determine whether isoflavones can cut the risk of bone fractures, a major cause of disability among older adults.
Also unclear, Bingham noted, is whether a soy-rich diet might be more or less beneficial than isoflavones supplements when it comes to bone health. The supplement her team studied is derived from red clover.
The study involved women ages 49 to 65, most of whom were postmenopausal and all of whom had recently had a mammogram to screen for breast cancer. Women with a history of the disease were excluded.
At the end of the study, women in the supplement group had lost less bone density in the lumbar spine than those in the placebo group had. There was no clear difference between the groups as far as bone density in the hip, according to the report.
To help ward off the bone-thinning disease osteoporosis, experts advise women to get enough calcium and vitamin D, avoid smoking and exercise regularly throughout their lives.
Story by Amy Norton
Story Date: 11/3/2004
Reuters News Service 2003
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