Sunshine and Vitamin D: A Catch 22

I don't want to rub it in for those of you living in more northern locales, but I'm sitting on my back porch today enjoying a 72 degree, perfectly sunny day in mid-February. (This is one of the many reasons why I love living in Austin, TX!) But even in Austin, we've had a pretty rainy and cold winter as far as winters go. For those of you living in Minnesota, no laughing please. And that means there has not been a whole lot of sunshine, which I usually take for granted.

In medical school (almost 20 years ago now - wow, time flies), I learned that sunshine is a key catalyst for humans to convert a chemical in our bodies to vitamin D. And, vitamin D is essential for our body to absorb and utilize calcium and phosphorous - thus, it's critical for healthy bones. Only recently has research pointed to even greater health benefits, like protection from certain types of cancers, autoimmune diseases, and high blood pressure.

The sun, not our diet, used to be the easiest way to obtain vitamin D. That is, until sunblock was developed to protect us from dangerous UV rays and skin cancer - hence the Catch 22. You have to choose the lesser of two evils...skin cancer or vitamin D deficiency.

You may not realize this, but very few foods contain vitamin D naturally. Milk is actually fortified with vitamin D - it's not in there when it comes from the cow. And even then, almost no one drinks enough milk to reach her daily vitamin D requirements. (More on this below). Cod liver oil is a good source of Vitamin D, but not too many people (adults or kids) guzzle this stuff.

Well, I also graduated from medical school thinking I'd never have a vitamin D deficiency living in a sunny place like Texas - especially since I'll sit outside and enjoy the sunshine for 15 minutes everyday without sunblock on (don't tell my dermatologist). Wrong.

Since vitamin D deficiency and vitamin D's health benefits have been such a hot topic of late, I asked my family doctor to test my vitamin D level at my annual physical recently.

At first, she laughed and said, "You're going to be deficient. Everyone is."

I replied, "Humor me. If I see how bad my numbers are, I'll be more inspired to take that vitamin supplement you're going to prescribe."

Well, the joke was on me. My vitamin D level was so low, it didn't even register! I am being a good patient and taking my vitamin D replacement pills now and will be taking a supplement going forward. I'm also going to encourage my own patients (even more than I already have) to take vitamin D supplements after this little experiment.

According to the American Academy of Pediatrics, babies under one year of age who are breastfed or who drink less than 32 oz a day of formula need 400 IU of a vitamin D supplement once a day. Infant vitamin supplements like Tri-Vi-Sol or D-Vi-Sol both have 400 IU per dropperful. And, after your child's first birthday, he also needs 400 IU of vitamin D a day. There's 100 IU of vitamin D per 8 oz of cow's milk (whole or 2%). So, if your child drinks the recommended 16 oz a day from age 1-3, he still lacks 200 IU of vitamin D a day. And once your child turns 3, if he isn't drinking at least a quart (32 oz) of skim or non-fat milk a day, he also needs a vitamin D supplement.

And, since many adults are also vitamin D deficient, you might want to consider picking up 1000 IU vitamin D supplements for yourself. And, take a moment to enjoy the sunshine if you've got any where you are!


- Ari Brown, MD, FAAP



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