Heart disease is the leading cause of death in the industrialized world, and kills 869,000 people in the U.S. each year, according to the American Heart Association. Deaths from heart disease rise in the winter, at higher latitudes and lower latitudes, where exposure to sun declines, the researchers said.
They tracked the health history of 18,225 men in the Health Professionals Follow-Up Study, comparing those who had a heart attack or died from heart disease with healthy participants. Men with a vitamin D deficiency at the start of the study were more than twice as likely to have a heart attack as those in the normal range, even after other reasons such as family history, weight, diabetes and cholesterol levels were considered.
``The risk of dying of a heart attack was even higher,'' said Edward Giovannucci, the lead researcher and professor of nutrition and epidemiology at the Harvard School of Public Health in Boston, in a telephone interview. ``Particularly for people who live in the northern-most states and in the winter months, when we don't get a lot of exposure to sunlight, 1,000 to 1,500 units a day of Vitamin D may be warranted.''
The study, funded by the National Heart, Lung and Blood Institute and the National Cancer Institute, appears in today's Archives of Internal Medicine. Previous studies found women who don't get enough sunlight may be at greater risk from aggressive breast cancer.
Sunny Days
Sunshine is the greatest source of vitamin D, produced when ultraviolet light strikes the skin. Studies have shown vitamin D, which occurs naturally in few foods, may make several types of cancer less lethal and protect against breast cancer, the most common malignancy in women.
On a sunny day in the summer, just 10 minutes outside in shorts and a T-shirt will generate enough vitamin D to reach the higher levels found protective in the study, Giovannucci said. Light-skinned people, the group with the highest risk of skin cancer, are the most efficient at producing vitamin D and need the least time in the sun, he said. Darker-skinned people need two to three times longer, he said.
``The people most concerned about skin cancer should definitely not be baking in the sun, but for about 10 minutes at midday, you can make a lot of vitamin D quickly,'' he said. ``You don't need to get a sunburn to make vitamin D.''
Sunscreen
Sunscreen partially blocks vitamin D production, particularly when lotions with higher sun protection factor, or SPF, levels are used. Some vitamin D is produced even when sunscreen is applied thoroughly, something most people don't do, according to the National Institutes of Health Office of Dietary Supplements.
In the winter, spending an entire day outside might not yield much vitamin D, Giovannucci said. And it may take 10 to 15 glasses of milk to raise men from the lowest levels to the highest, he said. It is during those winter months that supplements may be helpful, he said.
The reason for the protective effect of vitamin D isn't clear, though there are several hypotheses, he said.
Vitamin D can help lower blood pressure and reduce calcium deposits in the arteries, the fatty plaque that can rupture to cause clots and heart attacks, he said. It may also help reduce the risk of respiratory ailments that can be tied to heart attacks or help the heart muscle function better, he said.
To contact the reporter on this story: Michelle Fay Cortez in Minneapolis at mcortez@bloomberg.net
No comments:
Post a Comment