The sunshine vitamin

by Elizabeth Walker, Ph.D.

This article was originally published in January 2005

(January 2005) — You don’t need me to tell you that in a typical western Washington winter, we don’t get enough sunlight. The days are short, the clouds thick, and most of us work inside during daylight hours. But you may not know that as a result of this sun deprivation, more than half of us may be clinically deficient in vitamin D.

We make vitamin D when ultraviolet (UV) light reaches our skin, but this far from the equator the angle of the sun is too low for the UV rays to get through the atmosphere. Even if we sunbathed naked in the winter, we wouldn’t make any vitamin D.

If you were out in the sun last summer, you may have stored enough vitamin D to last for a few months, but by January those stores are likely to be low. And even if you are taking a multi-supplement, it probably doesn’t have as much D as recent research says we need.

So, what are the health effects of this deficiency? We’ve known for decades that vitamin D helps our bodies absorb and use calcium. The new research from The Vitamin D Council (see shows that it also works as a powerful regulator of cell growth, immunity and energy metabolism, with the potential to prevent and perhaps treat the following health problems:

  • Rickets in children and osteoporosis in adults. We absorb 65 percent more calcium when we have sufficient vitamin D.
  • Cancers of the breast, colon, prostate and probably other organs
  • Hypertension and heart disease, with supplemental vitamin D as effective as most medications in lowering blood pressure
  • Multiple sclerosis, type 1 diabetes, lupus, inflammatory bowel disease and other autoimmune illnesses
  • Type 2 diabetes and other problems related to high insulin levels
  • Joint pain, muscle weakness, fibromyalgia and balance problems
  • Gum disease and tooth loss
  • Seasonal Affective Disorder (SAD) and non-seasonal depression. (Light boxes and winter sunshine, improve mood but don’t make vitamin D. One study showed that high doses of vitamin D were even more effective than light therapy in treating SAD. In my counseling practice, where I see lots of people with depression, I advocate all three — outdoor light, light boxes, and supplemental vitamin D.)

The new research indicates that to get all the benefits of vitamin D, we need 1,000 to 4,000 IU/day, much more than the 400 IU commonly recommended and found in most multi-supplements. Although the Food and Nutrition Board recommended in 1997 an upper limit of 2,000 IU, a recent study in “The American Journal of Clinical Nutrition” concluded that 4,000 IU/day is safe for adults. To put it in a bigger perspective, we make 10,000 IU naturally with a few minutes of summer sunshine.

Vitamin D is found in only a few foods, including fatty fish (300 IU/serving) and milk (100 IU/cup). Some kinds of soymilk and orange juice are fortified with 100 IU/cup. Cod liver oil has 400 IU/teaspoon. Obviously, we can’t easily get the recommended amount from foods alone, so most of us need a supplement, at least in the winter.

The safest and most effective form is vitamin D3, also called cholecalciferol. A good basic dose is 1,000 IU in addition to food and a multi. If you have a special need for vitamin D and want to take more than 2,000 IU, a prudent course would be to take it for a few weeks to get your stores up and then ask your doctor for periodic blood tests to make sure you are getting enough but not too much. Ask for the test for 25-hydroxy vitamin D, and look for blood levels of 35-55 ng/mL.

And when the sun returns next spring, remember we can make all the vitamin D we need with just a few minutes of sunshine on skin without sunscreen. We get plenty from one-fourth of the time that would produce a mild sunburn, as little as five to 15 minutes at midday on exposed arms and legs for a pale-skinned person, or up to an hour for a dark-skinned person, each three times a week.

More exposure than this, especially enough to get a sunburn, will increase the risk of skin cancer, so after your brief exposure cover up with clothes or sunscreen. Like many things in health, a little is good, but too much can be harmful. Those at high risk of skin cancer might choose to avoid sunshine and take extra vitamin D supplements all year.

If we get adequate sunshine in the summer, we will store enough to last for several months after the sun stays low, but then we’ll run out again before the winter is over. Unless, of course, we can swing a midwinter trip to a vacation spot near the equator in the interest of strong bones, healthy cells, and joyful nervous systems.

Sources and research information available on request. Contact Elizabeth Walker at 206-725-6926 or email

Elizabeth Walker, M.S., Ph.D., is a counselor in private practice in Seattle. She provides her clients with holistic alternatives to Prozac and Ritalin, including neurofeedback, psychotherapy, energy psychology, nutrition education and light therapy. For a brochure on these services or to subscribe to her free email newsletter on mindbody health, contact her at 206-725-6926 or

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