Low Vitamin D Levels May Raise Heart Risk
Study Shows Vitamin D Supplements May Be Useful in Preventing Heart Disease
By
Charlene Laino
WebMD Health News
Reviewed By
Louise Chang, MD
Nov. 16, 2009 (Orlando, Fla.) -- Some men with low levels of vitamin D in
their blood are at particularly high risk of developing heart disease and
weakened bones that can lead to osteoporosis, researchers report.
In a study of more than 1,000 men, those with low levels of both
vitamin D and the sex hormone estrogen were at significantly increased risk of
having cardiovascular disease, says study head Erin Michos, MD, a cardiologist
at Johns Hopkins.
"They were also at dramatically increased risk of osteopenia," or bone loss
that can lead to osteoporosis, she says.
"Our results suggest that vitamin D supplements, which are already
prescribed to treat osteoporosis, may also be useful in preventing heart
disease," Michos tells WebMD.
Men with low levels of vitamin D and testosterone, on the other hand, were
not at heightened risk for heart disease or osteopenia.
Role of Estrogen and Vitamin D
The new findings build on previous studies showing that low levels of
vitamin D and estrogen, a sex hormone found in differing amounts in men and
women, are independent risk factors for developing plaque-laden arteries and
weakened bones.
The new study confirmed that men who had low levels of estrogen were at
increased risk of both heart disease and osteopenia.
And if both estrogen and vitamin D levels were depressed, the men's rates of
heart and bone disease were even higher, Michos says.
Michos and colleagues now plan to analyze blood samples from women to see if
the same results hold true for them. Studies are also under way to determine
whether vitamin D supplements can cut the risk of heart attack, stroke, and
osteoporosis.
The findings were presented at the annual meeting of the American Heart
Association (AHA).
How to Get Enough Vitamin D
Previous research showed that 41% of men and 53% percent of women are
deficient, with vitamin D levels below 28 nanograms per milliliter, Michos
says.
The Institute of Medicine suggests that an adequate daily intake of vitamin
D is between 200 and 400 international units for children and adults up to age
70. But Michos feels this is inadequate to achieve optimal nutrient blood
levels.
Michos recommends that men and women boost their vitamin D levels by eating
diets rich in fatty fish, such as cod, sardines, and mackerel. She also
suggests consuming fortified dairy products, taking vitamin supplements, and
briefly exposing skin to the sun's vitamin-D-producing ultraviolet light.
AHA spokeswoman Alice Lichtenstein, DSc, a nutritionist at Tufts University,
says the new studies add to growing evidence suggesting a link between vitamin
D insufficiency and cardiovascular disease.
But until well-designed studies show that vitamin D can improve heart
health, people should refrain from taking mega-supplements on their own, she
says.
"People sometimes think if a little is good, a lot is better. But that's not
always true. Too much vitamin D can build up and be toxic to organs like the
kidney," Lichtenstein says.
Low Levels of Vitamin D Linked to Stroke
Also at the meeting, Utah researchers reported that low levels of vitamin D
may raise the risk of stroke, heart disease, and death.
The researchers followed 27,686 people, ages 50 and older, with no history
of cardiovascular disease. The participants were divided into three groups
based on their vitamin D levels: normal (more than 30 nanograms per
milliliter), low (15 to 30 nanograms per milliliter), or very low (less than 15
nanograms per milliliter).
After one year, those with very low levels of vitamin D were 77% more likely
to die, 45% more likely to develop heart disease, and 78% more likely to have a
stroke, compared with people with normal vitamin D levels.
"We concluded that among patients 50 years of age or older, even a moderate
deficiency of vitamin D levels was associated with developing coronary artery
disease, heart failure, stroke and death," says researcher Heidi May, PhD, an
epidemiologist with the Intermountain Medical Center in Murray, Utah.
SOURCES: American Heart Association Scientific Sessions 2009, Orlando, Fla., Nov. 15-19, 2009.
Erin Michos, MD, Johns Hopkins.
Alice Lichtenstein, DSc, Tufts University.
Heidi May, PhD, Intermountain Medical Center, Murray, Utah.
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