A really cool thing about vitamin D is that you can make it yourself, out of the cholesterol in your skin when it is exposed to sunlight. Most researchers think that you can make enough just from exposing your hands, arms and face or your back to the sun for 10-15 minutes a day 2-7x a week, without sunscreen. I thought I was doing myself a favor a while back by putting on sunscreen every day….Digging around in the scientific literature, I was surprised to find that there is by no means a consensus on sun exposure as the primary cause of skin cancer! North of San Luis Obispo or so, however, you can’t make vitamin D in your skin in the winter months. It’s so important that your body can store it for winter use, if you have enough.
Low vitamin D status is widespread. I’ve had two vegetarian and vegan friends break bones in the past couple of years, and, when their healing went slowly, they were tested and found out they had low vitamin D. Commercial milk is fortified with vitamin D, and so are other processed foods like breakfast cereal and breakfast bars, not generally foods I recommend. I don’t drink fortified milk, I drink raw milk, which still contains natural vitamin D but not a lot. Vitamin D is not well supplied in most diets. It is found in oily fish like sardines, salmon, mackerel, herring and tuna, shellfish, liver and other organ meats, butter, eggs, cheese, raw milk and fortified foods. While I try to include sustainable sources of these foods in my diet frequently, it is hard to meet even the RDA with food alone. Vitamin D2 is found in some mushrooms and small amounts in dark leafy greens, but this form is not easily used by the body.
For disease prevention and general health, the only supplement I take is high vitamin cod liver oil. I mail order it from a very conscientious company. Cod fisheries, as far as I have been able to find out, are abundant and well managed. From a Chinese medicine perspective, cod liver oil is a powerful kidney and liver yin tonic. It also contains those wonderful omega 3 fatty acids. Watch out, there is a lot of lesser quality cod and fish liver oil on the market, for example, the stuff sold at your average drug store. Look for a good balance of vitamins A and D, which work synergistically, while each protects against the toxicity of the other. Most important, I give it to my 5 year old. There is good reason why this is a traditional supplement for kids. A 2004 study found that daily cod liver oil and a multivitamin significantly reduced upper respiratory-related doctor’s office visits by urban kids. Read the abstract here: