Ahhh…. the sun just came out! It’s streaming through the window behind me warming my legs. Hopefully there’s no UV coating on this glass… I need my daily dose.

This morning felt so cold, I couldn’t believe it. And all day has been cloudy so far. Just another reminder to swallow those Vitamin D pills when I get home tonight from my long day up on the hill.

Up until about a year ago, I never paid Vitamin D much attention. All I really knew was the basics:

1. it works along with calcium and magnesium for bone health
2. your body makes it from sunshine
3. it’s added to pasteurized milk in this country
4. it’s fat soluble like Vitamin A- which means you can overdose because your body stores it instead of excreting it through sweat/urine.

Pretty much all common knowledge. It wasn’t until I went down to see the Endo in Houston that I learned that I had a severe vitamin D deficiency. (I found this very ironic, since until I moved to the Pacific Northwest, I felt like I spent my life baking in the sun.) That news meant, of course, that I had to find out more. And much to my surprise, this is one fascinating nutrient.

I’ve read that Vitamin D deficiency has been linked to iron deficiency. The reason may be that individuals who are iron deficient have trouble metabolizing Vitamin D…. but I think that it is likely more of a correlation than causal relationship. Persons with fat malabsorption often have Vitamin D deficiencies, meaning that it requires some dietary fat for absorption. Symptoms of fat malabsorption include diarrhea and oily stools… (sorry again to be graphic). Fat malabsorption is associated with a variety of medical conditions including… drum roll please: CELIAC DISEASE. And, like I mentioned before, people with celiac or other malabsorption problems (like Crohns, etc.) are also very likely to have iron deficiency.

On another point high caffeine intake (300mg/day, which is equivalent to 18 oz of regular coffee) inhibits both vitamin d and iron absorption from the diet. Just another reason for me to cut back… (it is just sooo hard! Starting tomorrow!)

BUT… diet is not the best way to get vitamin D anyways. Our bodies prefer to make it from the sun. 10 to 15 minutes of sun exposure at least two times per week to the face, arms, hands, or back without sunscreen is usually sufficient to provide adequate vitamin D. Of course, this news flies in the face of the recommendations of your dermatologist- all of whom push the sunscreen. Unfortunately, if you are slathering on the sunscreen (spf 8 and higher) you’re blocking the UV rays that your skin needs to produce the required amounts of Vitamin D.
Hmmmm…. skin cancer or rickets?

Just kidding.

What makes the sunlight issue more difficult is that many of us live in Northern latitudes where the angle of the sun and weather patterns hamper our best efforts to tan. Also playing a role are season, time of day, cloud cover, and smog, affect UV ray exposure and vitamin D synthesis. For example, sunlight exposure from November through February in Boston is insufficient to produce significant vitamin D synthesis in the skin. Complete cloud cover halves the energy of UV rays, and shade reduces it by 60%.

According to the National Weather Service’s data for the period between 1951-1995. There was an average of 67 clear days per year. That’s it. 71 days were partly cloudy and a whopping 227 days were ENTIRELY CLOUDY!!!!

I am severely deficient in Vitamin D and I get outside to run every day, and I’m fair-skinned (the more pigment in your skin, the more sun it takes to make adequate amounts of vit D). It is hard to imagine how anyone here could be high without a supplement.

So, why does any of this matter?

There have been hosts of more recent studies that have linked high levels of vitamin D in the body to much decreased incidences of cancer, autoimmune diseases, and Alzheimer’s, among others. What is very interesting is that the levels needed for this kind of disease prevention are far above those needed merely for optimal bone health. These findings have led to an increased awareness of the nutrient and talks to increase the federal government’s RDA, which is currently a pathetic 200 IUs for adults under 50.

One of the most interesting tidbits for me is that Vitamin D functions more like a hormone in your body than it does like an actual vitamin. It affects your calcium absorption, thyroid, and immune system.

There are two types of Vitamin D commonly available in pill form: D2 and D3. D3, or cholecalciferol, has been found to be up to 10 times more potent that equal amounts of D2. The problem for vegans is that D3 is made from an animal source (Lanolin, which is derived from sheep’s wool). D2, on the other hand, is made from yeast and perfectly suited to vegans.

The upper limit for consumption of Vitamin D (D3) is about 2,000 IUs per day for adults. If you are deficient, your doctor will probably tell you to take more, or prescribe a 25,000 IU tablet that you take once per week.

In order to achieve the full benefit of the nutrient, many experts are recommending supplementing with 1,000 IUs of D3 per day.

Just please don’t use it as an excuse to drink more gross cow’s milk. The benefits of your increased vitamin D intake would come no where near to outweighing the health risks…. not to mention the acne and phlegmy mucus… but that is another post entirely.