About 20 million American women have osteoporosis, a
thinning of the bones that increases risk of bone fracture. Postmenopausal
women are particularly susceptible, because their estrogen production
has stopped. Estrogen plays an important role in slowing bone loss.
So after menopause, bone loss can increase dramatically, and some women
and their doctors may consider estrogen replacement therapy. Estrogen
replacement therapy has been shown to reduce bone loss and fractures,
but it carries some health risks.
As an alternative, taking over-the-counter soy isoflavone
supplements is becoming common among postmenopausal women. But there
is no documented scientific evidence of either their long-term safety
or efficacy in preventing osteoporosis.
William Wong, a nutritionist with the Children's Nutrition
Research Center (CNRC) at Baylor College of Medicine in Houston, Texas,
aims to get some answers to those two important questions. He is leading
a $4.5 million national study called OPUS (Osteoporosis Prevention Using
Soy) that will determine the benefits, safety, and correct dosages of
soy isoflavone supplements to prevent osteoporosis in postmenopausal
Begun in the spring of 2003, the project will enroll 400
women divided among CNRC, the University of Georgia in Athens, the University
of California at Davis, and the Kaiser Foundation Research Institute
in Oakland, California, and will follow them for 2 years. CNRC is the
coordination center, and Wong is the project director.
Though earlier studies have indicated that soy isoflavones
may help prevent osteoporosis and reduce symptoms of menopause, these
studies were usually short term and involved only a small number of
volunteers. OPUS is a long-term study of whether natural soy isoflavones
really are beneficial and safe. A third of the women will receive isoflavone
supplementation at 80 milligrams per day, a third will receive 120 milligrams
per day, and the remaining third will receive a placebo.
Confirming skeletal benefits from soy isoflavone consumption
could translate into reduced health care costs for treating osteoporosis
and increased production, sales, and consumption of an important U.S.
agricultural product. As a part of this study, funded by the U.S. Department
of Agriculture, findings will be disseminated to researchers, educators,
health care professionals, and consumers through Texas A&M University
and the Cooperative Extension System.
CNRC is operated by Baylor College of Medicine in cooperation
with Texas Children's Hospital and the Agricultural
Research Service.By Alfredo
Flores, Agricultural Research Service Information Staff.
William W. Wong
is at the USDA-ARS Children's
Nutrition Research Center at the Baylor College of Medicine, 1100
Bates St., Houston, TX 77030; phone (713) 798-7168.
"Soy Supplements and Bone Health" was published in
2004 issue of Agricultural Research magazine.