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Safety of DHEA?
Publicity on Diet Supplement for Senior Citizens
Needs Caution Sign
Nov. 12, 2004 - An over-the-counter hormone
supplement reduces belly fat and the chance of diabetes in older adults,
says a study reported this week in the Journal of the American Medical
Association. But, this was a study with only 56 participants and the
supplement known as DHEA has not been highly regarded in the past.
(See statement by National
Institute on Aging below story.)
The study claims to be the first to show DHEA (dehydroepiandrosterone)
decreases abdominal obesity and increases muscle mass. Abdominal fat
shrank by 10.2 percent in women and 7.4 percent in men, on average,
among participants 65 to 78 years old.
"It is a very promising finding that needs to be
confirmed with a larger, confined study," said Dr. Dennis Villareal,
lead author and a geriatrics professor at Washington University School
of Medicine.
"The replacement of DHEA, at doses of 50 milligrams
per day, brought back DHEA levels in older persons to the range seen in
youth. This resulted in a reduction in abdominal fat that was
accompanied by an improvement in insulin action," added Dr. Villareal.
He did caution that it's still much too early to
officially recommend DHEA as a weight-loss supplement.
Two Arizona researchers however warned that the
supplement could pose problems, especially for women, by potentially
increasing their risk of heart attacks. And its effect on younger people
is unknown, according to The Tucson
Citizen.
Brent Alva, a professor of exercise and wellness at
Arizona State University East, said consumers shouldn't take DHEA
without first checking with their doctors.
Ronald Watson, a professor of public health at the
University of Arizona, said the findings make sense but warned against
reading too much into the study, especially for younger adults.
DHEA has also been promoted as an “anti-aging”
remedy. A report by the National Institute on Aging says, “Researchers
are concerned that DHEA supplements may cause high levels of estrogen or
testosterone in some people.”
The NIA also warned, “Although the long-term (over
one year) effects of DHEA supplements have not been studied, there are
early signs that these supplements, even when taken briefly, may have
several detrimental effects on the body including liver damage.”
The study appears in the Nov. 10 issue of the
Journal of the American Medical Association.
National Institute on Aging
DHEA
Dehydroepiandrosterone or DHEA is made from
cholesterol by the adrenal glands, which sit on top of each kidney.
Production of this substance peaks in the mid-20s, and gradually
declines with age in most people. What this drop means or how it affects
the aging process, if at all, is unclear. In fact, scientists are
somewhat mystified by DHEA and have not fully sorted out what it does in
the body. However, researchers do know that the body converts DHEA into
two hormones that are known to affect us in many ways: estrogen and
testosterone (see below).
Supplements of DHEA can be bought without a
prescription and are sold as “anti-aging remedies.” Some proponents of
these products claim that DHEA supplements improve energy, strength, and
immunity. DHEA is also said to increase muscle and decrease fat. Right
now there is no consistent evidence that DHEA supplements do any of
these things in people, and there is little scientific evidence to
support the use of DHEA as a “rejuvenating” hormone. Although the
long-term (over one year) effects of DHEA supplements have not been
studied, there are early signs that these supplements, even when taken
briefly, may have several detrimental effects on the body including
liver damage.
In addition, some people's bodies make more
estrogen and testosterone from DHEA than others. There is no way to
predict who will make more and who will make less. Researchers are
concerned that DHEA supplements may cause high levels of estrogen or
testosterone in some people. This is important because testosterone may
play a role in prostate cancer, and higher levels of estrogen are
associated with an increased risk of breast cancer. It is not yet known
for certain if supplements of estrogen and testosterone, or supplements
of DHEA, also increase the risk of developing these types of cancer. In
women, high testosterone levels can cause acne and growth of facial
hair.
Overall, the studies that have been done so far do
not provide a clear picture of the risks and benefits of DHEA. For
example, some studies in older people show that DHEA helps build muscle,
but other studies do not. Researchers are working to find more definite
answers about DHEA's effects on aging, muscles, and the immune system.
In the meantime, people who are thinking about taking supplements of
this hormone should understand that its effects are not fully known.
Some of these unknown effects might turn out to be harmful.
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