Welcome to our Educational Resource (E-Source), an informative newsletter that keeps you up-to-date on current nutritional supplement information and gives you advice about use and effectiveness from a physician.

There is a great deal of confusion in the public and in the medical profession about vitamin D. Is it a hormone or is it a vitamin? And why is it an important issue? Calling it a vitamin makes us think that it really is a vitamin, a vitamin being defined as something that our body needs and cannot make. The answer is that it is both. Yet vitamin D is really more of a hormone than a vitamin. Let me explain.

When our skin is exposed to ultraviolet light in sunshine, our skin begins the manufacture of vitamin D. This provitamin D is then passed first to the liver and then to the kidneys, where the fully functional vitamin D is finally made. I have read various estimates, but in 20 minutes of full body sun exposure, our bodies can make 10,000 or 20,000 IU’s of vitamin D. It varies of course upon time of day, latitude, skin pigmentation and our age. The point is that it does not take a long time to make a lot of vitamin D, and the amount made is quite large.

There are problems, since in winter, especially in northern climates, we are limited by lack of sunshine and skin exposure, thus making vitamin D a true vitamin in the winter. While vitamin D can be stored for several weeks, we cannot store enough to last us through a typical winter. An additional factor in considering making our own vitamin D through sun exposure has been the advice of the medical profession about limiting sun exposure with clothing and sunscreens. Looking at the American Academy of Dermatology website, the advice is to avoid sun and to get your D through supplements. I’m glad they didn’t say to get vitamin D through our food, because Vitamin D is almost non-existent in our diet. I do not feel that this is good advice.

Historically, we have gotten our vitamin D through cod liver oil, which we have taken as a supplement for decades, fish oil being one of the few dietary sources of D. Since the 1950’s, we have had our milk fortified with ergocalciferol, or D2, derived from plant sources. While D2 has some vitamin D activity and has an effect in preventing rickets, it is not the cholecalciferol, or D3, which is human vitamin D. Thus if we are really going to try to get D3 from our diet, we are very limited indeed, certainly nowhere near the 10 to 20,000 IU’s that we can make for ourselves with just a little sunshine. To get that much requires supplementation. It seems that we were made to get our vitamin D from sunshine on our skin and not through our food. I believe the bottom line is to maximize our vitamin D levels through sun-exposed skin when we can (unless you have extremely sun-sensitive skin), and supplement during the winter months.

The AMA in June 2008 just issued a request to the FDA to re-evaluate the recommendations for vitamin D, suggesting that the current recommended levels of 200 IU (400 IU over age 50 and 600 IU over age 70) are way to low. Most of the current research suggests 4-5,000 IU is a better figure. The risks of toxicity have been over-estimated, and do not seem to occur below 40,000 IU daily intake for sometime. The better formulated multivitamins, such as the Perfect Multi, Perfect Multi Super Greens, and Perfect Multi Focus, now have 2,000 IU of vitamin D3 in them. Vitamin D3 can also taken as an individual supplement in pill form from Vital Nutrients of either 2000 IU or 5000 IU, or as a liquid in drop form (Liqui-D3), where each drop contains 2000 IU of D3. My recommendation is 4 or 5,000 IU daily if you are not getting sun exposure.

You will be hearing much more about vitamin D3 in the news in coming months. It is coming none too soon.