Known as the "sunshine vitamin" because the body naturally manufacturers the vitamin after exposure to the sun, vitamin D is crucial in helping the body absorb calcium-critical in maintaining strong bones-and in keeping normal blood levels of calcium and phosphorus. In fact, vitamin D is so important to good health, research is showing that vitamin D may also provide protection against hypertension (high blood pressure), cancer and some autoimmune diseases.
Now studies are showing potential protective heart benefits as well. Findings presented at the annual meeting of the American Heart Association found that some men with low levels of vitamin D and the sex hormone estrogen were at greater risk of having cardiovascular disease. The findings correspond to previous studies showing that low levels of vitamin D and estrogen, which is found in differing amounts in both men and women, are independent risk factors for developing clogged arteries and weakened bones. Studies in both men and women are also showing a correlation between low levels of vitamin D and increased risk of stroke, heart disease and death.
How much vitamin D should you be getting? The exact amount is now being debated. The recommendations from the Food and Nutrition Board at the Institute of Medicine (IOM) call for 200 IUs of vitamin D daily from birth to age 50 and then 400 IUs to age 70. But new evidence is prompting the IOM to reevaluate how much vitamin D individuals actually need and which doses are safe. Current IOM guidelines say individuals shouldn't go above 2,000 IUs daily-too much vitamin D can lead to nausea and kidney stones-but some vitamin D proponents say as much as 4,000 IUs a day for adults is safe, others say between 800 IUs and 1,000 IUs is enough to prevent health deficiencies. New IOM recommendations are expected in May.
In the meantime, check with your doctor to see what your vitamin D levels are and whether you should be taking a supplement. Healthy levels should be above 50 ng/ml.
Good food sources of vitamin D include fatty fish such as salmon, tuna and mackerel and fortified foods like milk, orange juice and some breakfast cereals. Exposing your skin to 10 to 15 minutes of sunshine three times a week may also produce enough of your body's requirement of vitamin D.
