It’s summer! I have seen many tanned (and some red!) faces in the office this past month. Does all of this sun exposure, the best source of vitamin D, mean that you don’t need your normal supplement? This is a question I am asked frequently, and I hope that the information below will help answer that question.
Why the sun isn’t enough:
- Sunscreen over SPF 8 will block the sun’s ability to make vitamin D
- Caucasians need approximately 20 minutes per day between 10 and 2pm of direct sunlight, most of skin uncovered, to make their daily dose of vitamin D
- African-Americans, or other dark skinned individuals, need approximately 1 hour to make their daily dose
- The ability to make vitamin D depends at latitude and time of year. In areas north of 35-37 degrees latitude, little to no vitamin D is made November to February.
So between the sunscreen, lack of time outside during daylight hours and varying geographical chance of exposure, its no surprise so many people are vitamin D deficient. According to many, optimal levels for disease prevention should be greater than 50 ng/mL.
Did you know that vitamin D acts more like a hormone in the body? It’s effects are far reaching and still being studied! The recommended supplemental dose of vitamin D varies by healthcare practitioner and depends on the individual. The recommended adequate intake, according to the Institute of Medicine is 200 IU’s per day, which really is only adequate in that it prevents rickets. According to the American Academy of Dermatology’s position statement on Vitamin D, “Adults who regularly and properly practice photoprotection may also be at risk for vitamin D insufficiency, and may be considered for a daily total dose of 1000 IU vitamin D.”
Diet is the only other source of vitamin D and is found in a limited number of foods. Many people rely on their milk intake as an adequate dose, but unless you find yourself drinking approximately 10 eight ounce glasses of milk fortified with vitamin D per day, you might not be getting a therapeutic dose through diet alone.
Diet, supplementation and sun are the only options in this game. With the potential harm that the sun can cause and the dietary challenge of obtaining therapeutic doses, it seems like an easy solution to the battle is to have blood levels checked and simply take some vitamin D.