CHICAGO (Reuters) - Adults with a vitamin D deficiency are more likely to
die than those with high levels, another indication of the nutrient's vital role
in guarding against ailments from heart disease to cancer, U.S. researchers said
on Monday.
The report follows several recent studies that have shown vitamin D may protect
against ailments including heart disease, cancers of the colon and breast,
diabetes and tuberculosis.
Those with the lowest levels of the "sunshine vitamin" had a 26 percent
increased risk of death over eight years compared to those with the highest
levels, the researchers reported in the Archives of Internal Medicine.
Dr. Erin Michos of Johns Hopkins University in Baltimore and colleagues
including Dr. Michal Melamed, who is now at the Albert Einstein College of
Medicine in New York, studied 13,331 adults for an average of 8.7 years.
Of the 1,806 people who died, 777 died of heart disease. Vitamin D deficiency
was also linked to a higher risk of death from cancer, diabetes and other
diseases.
"We think we have additional evidence to consider adding vitamin D deficiency as
a distinct and separate risk factor for death from cardiovascular disease,
putting it alongside much better known and understood risk factors such as age,
gender, family history, smoking, high blood cholesterol levels, high blood
pressure, lack of exercise, obesity and diabetes," Michos said in a statement.
Scientists have evidence that Vitamin D helps lower blood pressure, reduce
inflammation and boost the immune system.
"The fact that all the deaths went up, but we could not find the specific cause,
may be because vitamin D plays a role in both cancer and heart disease and
potentially other things" like diabetes, Melamed said in a telephone interview.
Vitamin D deficiency is common: about one-quarter of U.S. adults have less than
the 18 nanograms per milliliter of blood Melamed recommended as minimal. About
two in five American men and half of women have less than the 28 nanograms per
milliliter considered healthy.
The body makes vitamin D when skin is exposed to sunlight, and it is also found
in fatty fish like salmon. But many people get too little, especially in winter.
The vitamin is added to milk and other foods in many countries.
But too-high levels were also found to be harmful, Melamed said, although not as
harmful as deficiency.
How vitamin D works on the molecular level is unclear, but it can improve bone
health by helping absorb calcium. Receptors for the vitamin have been found on
the pancreatic cells that produce insulin.
"It's amazing the things that vitamin D has been associated with. I think part
of that may be that it's used as a messenger system, it's a hormone in the body,
and once the body finds a good messenger system, it uses it for a lot of
different things," Melamed said.
