You may need more vitamin D than you're getting. Our bodies can make vitamin D from sunlight, but at this time of the year the sun is not strong enough in the Bay Area for us to make any. Even if you were to go outside and sun bathe from mid-October to mid-March - and we've seen plenty of people getting out in the sun around Marin in the past few days - you're not making any vitamin D.
Vitamin D acts as a hormone in the body to regulate calcium, and vitamin D supplements may be even more important than calcium supplements in the prevention of osteoporosis. In the last few years vitamin D insufficiency has been linked to more than a dozen cancers, including colon, breast and prostate. Vitamin D insufficiency is also linked to Multiple Sclerosis, Parkinson's, Diabetes, Heart Disease, Blood Pressure, Infectious Diseases, Asthma, immune function, and autoimmune diseases. There are more than 2,000 genes directly or indirectly regulated by vitamin D. Every cell in the body has a vitamin D receptor.
The research is expanding rapidly and we are discovering that vitamin D is much more important than originally thought. One recent study showed children decreased their risk of getting the flu by 50 percent by taking vitamin D, while another study showed post-menopausal women who took vitamin D had a 60 percent lower risk of cancer. Vitamin D supplementation has also been shown to help treat Depression and Seasonal Affective Disorder (also known as The Winter Blues).
In our modern society, we spend most of our time indoors. When we do go outside, the medical community has effectively convinced us to cover up and wear sun screen at all times. The result has been an epidemic of vitamin D insufficiency. Approximately one third of otherwise healthy adults do not have adequate serum vitamin D levels, as do almost two thirds of hospital patients.
Vitamin D is not found in foods in great amounts. It has been added to some foods, particularly dairy foods to help prevent Rickets, a bone softening condition, in children. We need it in much higher amounts than we can get from foods. When we were evolving, near the equator, unclothed, we got all we needed from the sun. These days we need to get it from supplements. The Recommended Daily Allowance (RDA) of 600 international units is considered too little in light of recent research. Most experts agree that when the RDA panel meets again to set the recommendation, it will be raised to 1,000 units. The upper limit for safe intake is 2,500 units per day.
The best thing to do now is take up to 600 units per day, and have your blood levels checked next time you get a check up. Vitamin D is fat soluble and it is stored in the body for about three weeks. Now that the sun is weaker we can rely on our body's stores, but they will start running low in December, just in time for cold and flu season, and the Winter Blues. Take vitamin D supplements this season and see if it makes a difference for you.
Our bodies use vitamin D (sunshine) for so many purposes that you’d think we were plants. We seem to need it just as much.