Vitamin D - Possibly your best defense against flu and disease

Check out http://www.grc.com/health/Vitamin-D.htm and then read below for how to get your levels up if they are deficient.

From: Vitamin D Council

What We Recommend

If you use suntan parlors once a week or if you live in Florida and sunbathe once a week, year-round, do nothing. However, if you have little UVB exposure, my advice is as follows: healthy children under the age of 2 years should take 1,000 IU per day—over the age of 2, 2,000 IU per day. Well adults and adolescents should take 5,000 IU per day. Two months later have a 25-hydroxy-vitamin D blood test, either through ZRT or your doctor.

Start supplementing with the vitamin D before you have the blood test. Then adjust your dose so your 25(OH)D level is between 50–80 ng/ml, summer and winter. But remember, these are conservative dosage recommendations. Most people who avoid the sun—and virtually all dark-skinned people—will have to increase their dose once they find their blood level is still low, even after two months of the above dosage, especially in the winter. Some people may feel more comfortable ordering the blood test before they start adequate doses of vitamin D. We understand. Test as often as you feel the need to, just remember, no one can get toxic on the doses recommended above and some people will need even more.