On Vitamin D (notgames)

Several months ago, my wife Eve had a blood test and was subsequently informed by her physician that she was “very” deficient in vitamin D (also known as the “sunshine vitamin” because our bodies naturally generate it when exposed to solar UVB rays.) Since we live in Seattle, where it’s perpetually cloudy for approximately three-fourths of the year, Eve’s deficiency wasn’t too surprising. She started taking vitamin D supplements, and I started doing some research on vitamin D in general. I discovered three important things:

  • A very large percentage of 1st world residents are vitamin D deficient because we spend so much time indoors (and often use sunscreen when outdoors), and,
  • Vitamin D deficiency is linked to a disturbingly wide range of very serious diseases, including cancer, heart disease, autism, osteoporosis and multiple sclerosis, and,
  • Because the “daily recommended minimum” intake of vitamin D is 400 IU (the amount found in many multi-vitamins), many people mistakenly believe that a multi-vitamin is a sufficient source of vitamin D even if, like me, you go weeks at a time without significant sun exposure. Even people who get sun exposure before or after work may not be entirely OK; most UVB radiation penetrates the Earth’s atmosphere from approximately 10am to 3pm. The National Institute of Health recommends 5 to 30 minutes of sun exposure between those times at least twice a week, sans sunscreen, to people who wish to self-synthesize the recommended minimum amount of vitamin D.

Much of the available data about vitamin D presents a paradox that confuses many people. Vitamin D can be toxic in extremely high doses, so people are afraid to consume too much. On the other hand, if you investigate dosage limits, you’ll learn that just 30 minutes of full body sun exposure (at the right time of day) will cause the average person to synthesize 10,000 IU of vitamin D — 25 times the daily recommended minimum — which suggests that it’s pretty darn hard to overdose on vitamin D, but which also might make you think you don’t need supplements if you get any sun whatsoever. Unfortunately, for the reasons I mentioned earlier, most indoor office workers would probably still benefit from approximately 1,000 to 2,000 IU of vitamin D supplements per day (2.5x to 5x the daily recommended minimum.) At least, that’s what the experts say.

So, a few months ago, I started taking 2,000 IU regularly. Then, a few weeks ago, I visited my doctor and asked for a vitamin D blood test. The outcome? My vitamin D level was “slightly low.” I don’t even want to know what it looked like before I began taking supplements.

The ironic thing about me writing this post is that I’m a pretty serious skeptic when it comes to supplements of any kind. And for good reason: most studies have demonstrated little-to-no benefit from the vast majority of popular supplements. In fact, some well-regarded physicians have gone so far as to say that every supplement except vitamin D is a complete waste of money. A more balanced take on supplements can be found in this fantastic diagram, which visually depicts the varying levels of research supporting any given supplement. You’ll notice that very few supplements other than vitamin D and omega 3 make the cynic’s cut. My own physician heartily recommends both those supplements, and none other.

The bottom line is that, as of now, there’s enough evidence to support vitamin D supplementation for most indoor office workers. Of course, given the pretty dismal track record of even our most prestigious healthcare research institutions, I wouldn’t be surprised if ten years from now new studies dispute the benefits of supplementation. But I’ll take my chances (and heck, maybe I’ll even buy one of those UVB reptile sun lamps… it might help improve my mood during the long, dark Seattle winter!)

9 responses to “On Vitamin D (notgames)

  1. I used to think I couldn’t overdose on vit D, too. And the benefits seemed obvious with little risk. Multiple physicians told me to take 4,000 IU/day, which I did for a while because I had “severe” vit D deficiency (had almost none). Fast-forward a couple of years. In the most recent blood test, my vit D level was “too high!” I wasn’t even taking it every day–only when I remembered & felt like it. My endocrinologist tells me it’s 10 times as much as it should be (or something like that–3 digits instead of 1-2 digits), & if I keep at it it could cause calcium buildup in my body. So I’m holding off at the moment, not taking it every day :P Maybe I got sun AND took vit D? It remains a mystery. (But most of my conditions are mysterious so I’m used to that…) :D

  2. Hey Aya — 4,000 IU seems really high for a long term (i.e. multi-year) dosage. Everything I’ve read recommends 1,000 IU to 2,000 IU assuming very little sun exposure. But then again, I wouldn’t be at all surprised if different people required more or less for the appropriate effect! I think the most prudent course of action would be to get tested, start taking a given amount of supplement for a reasonable period of time (i.e. six months) and then get tested again to see how your body is reacting.

  3. you still get dosed with uv rays when it’s cloudy, that’s why people who work outdoors wear sunscreen regardless of the weather

  4. John — correct, but clouds do block approximately 50% of UVB rays.

  5. Another thing I forgot to mention: apparently UVB radiation does not penetrate glass, so exposure to sunshine indoors through a window does not produce vitamin D.

  6. Richard Nikoley has written quite a bit about his Vitamin D intake. http://freetheanimal.com/supplements I take it for the simple reason of boosting my immune system; I hate colds, so I will do almost whatever it takes to prevent them.

  7. Yeah, I got tested periodically about every 6 mo like you said (and I was taking it more like every other day or every 3 days :P), and it was like low -> low -> low -> low-normal -> boom! high. Our bodies are very mysterious sometimes ;) I got tested in Jan, so I’ll test again this month. That said, I hear most people who are darker than super-pale are vit D deficient in Seattle, so Daniel & I’d contemplated in the past opening a “vit D recharge salon” chain w/ special tanning machines where people can quickly/naturally re-charge their vit D. And I still take it.

  8. Quit all this jibba-jabba about supplements. You’re ruining my excuse to not bother with sunscreen.

  9. Any thoughts on sunlamps? Seattle is getting to me.

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