A lack of vitamin D, which is absorbed primarily through exposure to sunlight, helps boost the risk of heart attacks and strokes, new research finds.
"There is a whole array of studies linking increased cardiovascular risk with vitamin D deficiency," notes Dr. James H. O'Keefe, at the Mid America Heart Institute in Kansas City, Missouri.
"It is associated with major risk factors such as high blood pressure, diabetes, and stiffening of the left ventricle of the heart and blood vessels," he says. "Inflammation is really important for heart disease, and people with vitamin D deficiency have increased inflammation."
Dr. O'Keefe is the lead author of a review of such studies to be reported in the Journal of the American College of Cardiology.
Experts estimate that up to half of adults and 30 percent of children and teenagers in the United States are vitamin D-deficient, according to the report.
Recent data from the long-running Framingham Heart Study indicated that someone with vitamin D levels below 15 nanograms per milliliter of blood is twice as likely to suffer a heart attack, stroke, or other cardiovascular problem within two years as someone with the recommended 20 nanograms per milliliter, the report shows.
Vitamin D is well known as the "sunshine vitamin" because human skin makes the nutrient upon exposure to sunlight.
Only 10 minutes of exposure to sunlight between 10 am and 3 pm each day will be enough for Caucasians to reach the recommended level, experts say. People with darker skin will need somewhat longer exposure times.
Sunscreen can also block vitamin D production, the experts add, so people must balance the risks and benefits of sun exposure.
"A little bit of sunshine is a good thing, but the use of sunscreen to guard against skin cancer is important if you have more than 15 to 30 minutes of intense sunlight exposure," notes Dr. O'Keefe.
Some foods are also rich in vitamin D, he says. "Salmon and other deepwater fish are good. Also milk, which is supplemented with vitamin D, but you would have to drink 10 to 20 glasses of milk a day to get the recommended intake."
Recommended vitamin D intake is 200 international units a day up to age 50, 400 units for ages 50 to 70, and 600 units a day over the age of 70.
One way to reach that level is to take a supplement. "There is strong evidence that supplementing vitamin D improves health," notes Dr. O'Keefe.
"This is an important report," says Dr. Robert U. Simpson, a professor of pharmacology at the University of Michigan, whose group was the first to identify vitamin D receptors in heart cells. "It will help those interested in cardiovascular disease understand more about the vitamin D system."
Vitamin D is not just another vitamin, says Simpson. "It is a precursor to a hormone, and this prehormone is responsible for making a very important regulator of cardiovascular processes.”
Supplementation is an acceptable way of getting enough vitamin D, Simpson adds. "Food is not really an option. You don't get enough vitamin D in the foods we ordinarily eat.
Supplementation is my preferred choice, although I get sunlight whenever the sun shines here in Ann Arbor."
Always consult your physician for more information.
Improving eating habits and increasing physical activity play a vital role in heart health.
Eat five to nine servings of fruits and vegetables daily. A vegetable serving is one cup of raw vegetables or one-half cup of cooked vegetables or vegetable juice. A fruit serving is one piece of small to medium fresh fruit, one-half cup of canned or fresh fruit or fruit juice, or one-fourth cup of dried fruit.
Choose whole grain foods such as brown rice and whole wheat bread. Avoid highly processed foods made with refined white sugar, flour, and saturated fat.
Weigh and measure food in order to be able to gain an understanding of portion sizes. For example, a 3-ounce serving of meat is the size of a deck of cards. Avoid supersized menu items.
Balance the food "checkbook." Taking in more calories than are expended for energy will result in weight gain. Regularly monitor weight.
Avoid foods that are high in "energy density," or that have a lot of calories in a small amount of food.
For example, a large cheeseburger with a large order of fries may have almost 1,000 calories and 30 or more grams of fat.
By ordering a grilled chicken sandwich or a plain hamburger and a small salad with low-fat dressing, you can avoid hundreds of calories and eliminate much of the fat intake.
For dessert, have fruit or a piece of angel food cake rather than the "death by chocolate" special or three pieces of home-made pie.
Remember that much may be achieved with proper choices in serving sizes.
Accumulate at least 30 minutes or more of moderate-intensity activity on most, or preferably all, days of the week.
Examples of moderate intensity exercise are walking a 15-minute mile, or weeding and hoeing a garden.
Look for opportunities during the day to perform even ten or 15 minutes of some type of activity, such as walking around the block or up and down a few flights of stairs.
Always consult your physician for more information.