From foodconsumer.org
Low vitamin D linked to increased risk of peripheral arterial disease
By David Liu, Ph. D.
Apr 16, 2008 - 3:37:51 PM
WEDNESDAT April 16, 2008 (foodconsumer.org) -- Low levels of vitamin D may increase risk of peripheral arterial disease (PAD), according to a study reported at the American Heart Association’s Arteriosclerosis, Thrombosis and Vascular Biology Annual Conference 2008.
Results of the study were scheduled also to appear in Arteriosclerosis, Thrombosis, and Vascular Biology: Journal of the American Heart Association.
But the authors and the American Heart Association do not recommend people rush to start taking supplemental vitamin D other than suggesting use of a balanced diet to get adequate nutrients as more research is needed.
Peripheral arterial disease (PAD) is a condition in which a fatty material called plaque (plak) builds up on the inside walls of the arteries that carry blood from the heart to the head, internal organs, and limbs. PAD is also known as atherosclerotic peripheral arterial disease, according to The National Heart Lung and Blood institute.
PAD affects about 8 million Americans and is linked to significant disease and death, according to the American Heart Association’s Heart Disease and Stroke Statistics – 2008 Update.
Vitamin D, or 25-hydroxyl vitamin D, is known primarily to benefit bone health. Recent studies have showed high intake of this vitamin can also drastically reduce risk of a variety of cancer in addition to its association with cardiovascular disease.
"In animals, vitamin D has anti-inflammatory activity," said Michal Melamed, M.D., M.H.S., lead author of the study and assistant professor at Albert Einstein College of Medicine in New York City.
"In addition, in mice, vitamin D is a regulator of one of the hormone systems that affects blood pressure. The cells in the blood vessels in the body have receptors for vitamin D, so vitamin D may have direct effects on the vessels, although this has not been fully worked out."
For the study, Melamed and colleagues analyzed data from a national survey for vitamin D levels in 4,839 U.S. adults. The surveyors had also documented ankle-brachial index, a PAD screening tool that measures blood flow to the legs.
"We also measured other risk factors for peripheral arterial disease such as cholesterol levels, diabetes, blood pressure and inflammatory markers such as C-reactive protein," Melamed said.
Higher levels of vitamin D were correlated with a lower prevalence of PAD. In the participants with the highest vitamin D levels - more than 29.2 nanogram per milliliter (ng/mL) - only 3.7 percent had PAD compared to 8.1 percent among those with the lowest levels - less than 17.8 ng/mL.
"After adjusting for age, sex, race and co-existing health problems, we found adults in the lowest vitamin D group had a 64 percent higher prevalence of PAD compared to those with the highest vitamin D levels," Melamed said. "For each 10 ng/mL lower vitamin D level, there was a 29 percent higher risk of peripheral arterial disease."
The results, the researchers cautioned, did not mean that taking vitamin D supplements would render a protective effect although the possibility could not be excluded. One possibility is that vitamin D serves as a biomarker for a person's dietary habit and lifestyle, which are known to have an effect on the cardiovascular health.
A scientist affiliated with foodconsumer.org who was not part of the research team suggested that evidence from other studies is sufficient to recommend high intake of vitamin D for a variety of health benefits.
The current recommended daily allowance for adults under 51 is 200 international units and for adults over 50 is 400 IU. Vitamin D experts have already recommended the daily allowance should be increased to at least 1000 IU per day.
Dietary sources for vitamin D are limited. The food that is most rich in the vitamin is oily fish such as salmon fish. Eggs also contain some, but not a whole lot. Because of this, vitamin D is used to fortify a number of foods including orange juice, milk and cereal.
Sunshine is the best and cheapest source of vitamin D. Exposure of the face and hands to sunshine for 15 minutes per day is generally believed to be enough to get the amount a person needs.
But those who count on vitamin D for treatment or prevention of certain health condition, more than 1,000 or even 1500 IU are recommended. Up to 10,000 IU a day is considered safe.
But to prevent cardiovascular disease, one should not count on vitamin D alone, the foodconsumer.org scientist suggested. They should do their best to reduce the risk by controlling other risk factors such as cholesterol and saturated/trans fat among others.