December 15, 2009
Get Extra Sunshine with Vitamin D
The Word from WIC
by Heather Plaster, WIC Dietitian
Now that Old Man Winter has set in and the amount of sunlight is decreasing each day, it's time to talk about a vitamin that is directly affected in our bodies by sun exposure-vitamin D.
Vitamin D is a fat-soluble vitamin that is normally produced by the skin when UVB rays in sunlight are absorbed into the skin. Vitamin D serves an important role in preventing rickets (bones that are too soft) and osteoporosis (bones that are too brittle), as well as newly discovered roles in the immune system, the cardiovascular system, brain chemistry, and the inflammatory response.
In the body, vitamin D has the same chemical structure as a hormone and acts just like a hormone when it gets into the nucleus of the cell. Simply put, vitamin D does a lot of different things in the body in a lot of different places.
In ancient times, humans evolved this ability to produce vitamin D from sunlight because they lived closer to the equator and wore less clothing. In Alaska, however, the low winter sunlight and the need to wear warm clothing impairs the body's ability to produce vitamin D. Vitamin D is also found in foods such as fish (especially cod liver oil), fortified foods such as milk, eggs, and beef, but the typical Alaskan diet is still short on vitamin D from dietary sources.
Most Americans, even those in the sunny Lower 48, are vitamin D deficient. The recommended daily value is 400 IU (international units), but most Americans only get 100 IU each day. Even at the recommended amount, newer research is indicating that the daily value is too low and the recommendations may be revised as early as Spring 2010. So what's a typical Alaskan to do?
Well, dietitians usually like to preach getting all vitamins from the diet, but in the case of vitamin D, supplementation may really be a good idea, especially for the winter months. The supplements are fairly inexpensive and easy to take. I recommend that healthy adults take 1,000 IU of vitamin D per day, in the form of Vitamin D-3 (aka cholecalciferol), but first check in with your healthcare provider to see if you have any problems that contraindicate vitamin D (such as liver or kidney disorders). Try not to use the Vitamin D-2 supplements, because the D-3 form is more active in the body. Children should stick to 400 IU per day. Toxicity with vitamin D is rare, and the only known cases have occurred in individuals taking more than 40,000 IUs per day.
So, as the winter nights get longer, and the colder temperatures keep us huddled by the fire, give thought to whether you might need a vitamin D supplement to keep your bones strong and your body healthy so that, come breakup, you'll be ready to get out there and run in the sun!
