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Selenium Supplementation may Boost Cholesterol |
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Written by Adrian Wozniak
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Tuesday, 24 November 2009 |
Taking too much selenium, an essential mineral touted for immune boosting and anti-cancer benefits, could increase cholesterol levels by 10 percent and, as a result, raise the risk of heart disease, a new study suggests.
The findings, published online November 10 in the Journal of Nutrition,
a publication of the American Society for Nutrition, warns consumers
against taking too much selenium until more research is done to gain a
better understanding of the risks and benefits of selenium
supplementation.
Study co-author, Dr. Saverio Stranges of the Warwick Medical School in
Warwick, England, said the findings of this observational study are
"consistent with the findings of earlier clinical work," which have
suggested an association between elevated blood levels of selenium and
an increased risk of type 2 diabetes and high cholesterol.
Selenium is a mineral found in grains, nuts, fish and meats. Foods
grown and raised in selenium rich environments like the United States
have higher natural selenium content than those grown in selenium poor
areas, like China.
Not getting enough selenium can contribute to heart disease, an
underactive thyroid gland, and a weakened immune system. But, selenium
deficiency is rare in healthy populations like the United States where
a greater threat may be posed by getting too much.
"If you get more selenium than what you need ... there are no
additional benefits and actually there is the potential for adverse
effects," such as an increased risk of diabetes or high cholesterol,
Stranges noted in a telephone interview with Reuters Health.
As in the U.S., dietary supplement use is on the rise in the U.K.
Stranges and colleagues wanted to know if the findings of previous
selenium studies in the U.S. held true for Britain, where people are
exposed to less selenium in their environment.
The research team analyzed the 2000 and 2001 diets and health records
of more than a thousand British adults. Participants gave blood and
answered questions about smoking, drinking, exercise at work and at
play, prescription drug use, supplement use, income, and education.
Information about physical characteristics such as weight and height
was also gathered.
The researchers stopped short of claiming too much selenium causes a
boost in cholesterol but wrote that the association between selenium
levels in the blood and total cholesterol "was strong," and consistent
with earlier studies.
Cholesterol levels, the researchers found, rose in tandem with blood selenium concentrations.
The researchers caution that the benefits of antioxidants, like
selenium, have been aggressively marketed, despite "a lack of
definitive evidence on their efficacy for cancer and other chronic
disease prevention."
"We believe that the widespread use of selenium supplements or of any
other strategy that artificially increases selenium status above the
level required is unwarranted at the present time," Stranges said in a
prepared statement.
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