There are plenty of sources to be found

House Calls is published monthly. Today's article was written by Dody McLeod, a physician's assistant who works in the Ambulatory Surgery Department of Sutter Coast Hospital.

Odds are, if you live north of San Francisco, don't get outside for at least a 15-minute daily walk in the sun, are African-American and otherwise dark-skinned, are older, or overweight, you don't get enough vitamin D.

Vitamin D is necessary for the absorption of calcium and phosphorus for bone health. Rickets (a softening and weakening of bones in children) had largely been eradicated by the "enriching" of foods with vitamin D.

Unfortunately, we are seeing more cases of rickets these days. Most research points to the use of sunscreen in children and the fact that children are not playing outside as much as the cause.

Other symptoms of vitamin D deficiency are fatigue, general muscle pain and weakness, muscle cramps, joint pain, chronic pain, weight gain, hypertension, restless sleep, poor concentration and headaches. In children, Vitamin D is especially important for bone development.

One study suggested that half of American children were deficient in Vitamin D.And, depending on your geographic location, 30 to 100 percent of American adults can be deficient.

Vitamin D is found naturally occurring in wild fish, fish oils, egg yolks and mushrooms. It is also found in fortified foods such as grain and dairy.But sun exposure in moderation is the major source of Vitamin D.

Current recommendation for sun exposure is going outside during the summer without sunscreen (except for the face) and wearing limited clothing from 10 a.m. to 3 p.m., two to three times weekly for 5-10 minutes.

Sunscreen reduces exposure by 95andndash;98 percent.Vitamin D can quickly be restored by sunlight. Six days of casual sunlight exposure without sunscreen can make up for 49 days of no sunlight exposure.

People are especially at risk for deficiency if they live in Canada or the northern half of the United States. Other populations that are at risk for Vitamin D deficiency are; the elderly, obese individuals, exclusively breast-fed infants, and those who have limited sun exposure.Darker-skinned races are also more susceptible to deficiency, as they are not able to absorb the sun's rays as well.

Recent studies have suggested that vitamin D may provide protection from osteoporosis, hypertension (high blood pressure), cancer and several other autoimmune diseases.

If you feel that you may be deficient in Vitamin D, contact your health-care provider and he or she may order a simple blood test that can determine your levels. Recommended doses can vary and should be tailored to the individual.

So until then, enjoy that smoked salmon sandwich on vitamin enriched bread out in the sunshine and get your Vitamin D.