| |
July 6, 2004 (HealthDayNews)
While naturally occurring
phytoestrogens found in soy may still be of benefit for
younger women going through menopause, "women
over the age of 60 aren't necessarily going to gain any benefit
with regards to bone density, cholesterol-lowering effects
or effects on memory," concluded study co-author Johanna
Lampe, a nutritional biochemist at the Fred Hutchinson Cancer
Research Center in Seattle.
The findings appear in the July
7 issue of the Journal of the American Medical Association.
Postmenopausal reductions in circulating estrogen raise risks
for a variety of age-related conditions. For years, millions
of American women fought back with hormone replacement therapy
(HRT).
But in July 2002, a part of a large study called the
Women's Health Initiative was halted prematurely after researchers
found HRT raised risks for breast cancer, heart disease and
stroke. With HRT suddenly in disfavor, women began to look
for safer alternatives.
Enter soy, rich in naturally occurring
estrogen-like compounds called isoflavones.
"It's become
very popular," Lampe explained. "There were a number of small
studies that had shown potential effects of soy on bone mineral
density -- a risk factor for osteoporosis -- as well as effects
on cholesterol levels, in men. So many women looking for
alternatives to HRT are now turning to soy."
But has the
recent hype surrounding soy outstripped reality? To find
out, Lampe and a team of researchers led by Dr. Sanne Kreijkamp-Kaspers
of the University Medical Center in Utrecht, the Netherlands,
had 202 Dutch women aged 60 and older consume either 25 grams
of soy protein or a non-soy milk powder daily for a period
of one year.
The women were tested before and after the study
to assess their bone mineral density, cholesterol levels
and mental sharpness.
Unfortunately, according to Lampe, "soy had no effect on cholesterol levels,
bone mineral density or any of the memory and mental acuity tests that were done."
She
admits the researchers were "surprised" by the results, because smaller, less
rigorous studies conducted in the past had suggested some benefit for postmenopausal
women.
Still, "there actually hadn't been any studies done in any systematic fashion
in older women," Lampe pointed out. All of the previous studies cited most often
by either the scientific community or the media "had been done in earlier decades
[of life]," when the study participants were in their late 40s or 50s, she said. "It
may have been a case of making generalizations to a wider age range than was
necessarily appropriate," she said.
Soy may still be of benefit for younger women
going through symptoms of menopause, especially for its ability to ease hot flashes
and other problems. But for women over 60, the bean-based food appears to offer
little benefit outside of healthy nutrition.
So where does this leave older women
hoping to fight osteoporosis, high cholesterol and memory loss?
"I think this
is something a woman really needs to discuss with her physician," Lampe said. "There
are various medications that may be helpful, and, of course, lifestyle changes,
too. Each woman has to decide which of these three conditions is a high priority
for her, and make her decision based on that."
Dr. Thomas Clarkson, a researcher
at Wake Forest University, has long studied soy's effects on postmenopausal health.
He said he was not overly surprised by the Dutch findings, since his research
in both animals and humans suggests that soy isoflavones only improve a woman's
health through synergy with circulating estradiol, a female hormone.
"In the
absence of estradiol, there is no effect," Clarkson said. Because women past
the age of 60 retain only very small amounts of circulating estradiol, this could
explain the Dutch results, he said.
And because estradiol levels decline as menopause
proceeds, soy may only be helpful in relieving menopausal symptoms early in the
menopausal process. According to Clarkson, it's ultimate role might be as a complementary
--- not alternative -- therapy, "given alongside very low-dose estradiol therapy."
More
information To
learn more about hormones and menopause, visit the National
Institute on Aging.
Forbes.com
|
Menopause
