by William Menna

Created on: February 17, 2010

Vitamin D is a fat-soluble vitamin that is obtained primarily through sunlight.  The Mayo Clinic reports that the primary purpose of vitamin D in the body is to regulate the content of calcium and phosphorus in the blood stream.  A vitamin D deficiency can throw off these levels among other effects, leading to potential complications including reduced bone strength, high blood pressure, and an increased risk of various medical conditions including autoimmune diseases.

Lack of exposure to sunlight is the most frequent cause of vitamin D deficiency.  One of the main sources of vitamin D is simply sunlight.  By simply getting exposure to some sunlight a few times a week, the body’s vitamin D needs are often met independent of dietary vitamin D.  However, wearing sunscreen can actually severely inhibit the body’s ability to absorb the nutrient from sun rays.

People who don’t get outdoors much or who live in areas that receive little sunlight are at a higher risk of vitamin D deficiency.  Because of the method by which it is acquired, the winter season is often a cause of vitamin D deficiency.  In fact, it is believed that the lack of vitamin D acquired through sunlight during the winter months is at least partly responsible for the development of seasonal affective disorder.

Another partial cause of vitamin D deficiency is limited intake through the diet.  This is in large part due to the limited number of foods in which vitamin D naturally occurs.  Fish is the only true natural food source of a substantial amount of vitamin D.  Some other foods are fortified with vitamin D including milk, some dairy products, and certain kinds of juices and cereals.  Fish oil capsules and vitamin supplements are the easiest ways to get the recommended daily intake independent of sunlight.

Conditions affecting the absorption of the nutrient can also cause vitamin D deficiency.  According to the Linus Pauling Institute of Oregon State University, conditions that affect the absorption of fat like cystic fibrosis and cholestatic liver disease can cause vitamin D deficiency by hindering the body’s ability to absorb vitamin D.

Vitamin D is an essential nutrient responsible for a number of functions and immune boosting properties.  Lack of sunlight is the most frequent cause of vitamin D deficiency, but it can be associated with medical conditions that affect the body’s ability to digest or absorb certain nutrients.  Any questions about the causes of vitamin D deficiency should be directed to a primary care provider.

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