Low blood levels of vitamin D linked to heart attacks and strokes

Jan 7 2008

According to new research people who have low levels of vitamin D in their blood are at an increased risk for heart attack, heart failure and stroke.

The researchers say vitamin D offers protection against cardiovascular disease and the risk was particularly significant among those with high blood pressure.

It is already known that vitamin D, which is produced in the body by sunshine, offers a number of health benefits, but there are concerns that many people get too little vitamin D, especially those with dark skins, the elderly, pregnant women, and individuals who wear all-concealing clothing.

Vitamin D helps the body absorb calcium and is important for bone health, and is also thought to protect against certain cancers, diabetes and osteoporosis as well as possibly multiple sclerosis; in children a vitamin D deficiency can lead to rickets.

Apart from sunlight on the skin, vitamin D can be obtained from milk, eggs, oily fish, cod liver oil and some fortified cereals.

Researchers at Harvard Medical School in Boston followed 1,739 people with average age 59, for a 5 year period; all were descendants of the original participants in the Framingham Heart Study, a major investigation of heart disease risk factors which began in 1948; they had no prior history of cardiovascular disease and all were white.

In order to gauge vitamin D levels the researchers took blood samples from the participants and they found that those with low vitamin D levels had about a 60 percent higher risk of a cardiovascular event such as a heart attack, heart failure or a stroke compared to those with higher levels.

This remained even after well-known cardiovascular risk factors such as diabetes, high cholesterol and high blood pressure were taken into account.

The study which was led by Dr. Thomas Wang also found that the risk for heart attack, heart failure or stroke was double in people with both hypertension (high blood pressure) and vitamin D deficiency.

Dr. Wang says he believes it would be premature to state that vitamin D supplements would lower a person's risk for heart disease or stroke, and to recommend that people take such supplements for that purpose.

Dr. Wang says vitamin D deficiency is extremely common, especially in areas of the world that get little sunlight during the winter months but such a deficiency is easily remedied with changes in the diet or the addition of dietary supplements containing vitamin D.

Few foods are naturally rich in vitamin D, it is found in fatty fish such as salmon and milk is commonly fortified with the vitamin.

Experts suggest that exposure to 10 to 15 minutes of sunshine three times weekly is sufficient to produce the necessary vitamin D levels.

Dr. Wang says there is a growing body of new information which suggests that vitamin D may have some actions on the heart and major blood levels, therefore a lack of vitamin D may be associated with the development of cardiac abnormalities.

The findings were published in Circulation, a journal published by the American Heart Association.