The disease is becoming a growing threat to the health of millions of people in developed countries, owing to the ageing populations. The WHO has classed it as the second biggest public heatlh problem after heart disease.
Postmenopausal women are particularly susceptible because theiroestrogen production, which normally plays an important role in slowing bone loss, is greatly diminished. After menopause, bone loss can increase dramatically.
But hormone replacement therapy, shown to reduce bone loss and fractures, carries some health risks, and in countries, such as the UK, the medicines watchdog has advised it no longer be used for prevention of osteoporosis.
This in turn triggered the search for alternatives, including soy isoflavone supplements. But there is currently little scientific evidence of either their long-term safety or efficacy in preventing osteoporosis.
William W. Wong, based at the Children's Nutrition Research Center (CNRC) at Baylor College of Medicine in Houston, is leading a national study called OPUS (Osteoporosis Prevention Using Soy). It aims to determine the benefits, safety and correct dosages of soy isoflavone supplements to prevent osteoporosis in postmenopausal women.
It could finally resolve for the supplements industry whether isoflavone or other soy supplements can be marketed to help prevent osteoporosis.
The two-year, $4.5 million project, started last year, willinvolve 400 female volunteers divided between the CNRC in Houston, theUniversity of Georgia at Athens, the University of California at Davisand the Kaiser Foundation Research Institute in Oakland, California.
One-third of the women will receive 80milligrams (mg) of isoflavone supplementation per day, one-third willreceive 120 mg per day, and the remaining one-third will receive aplacebo.