Vitamin D, a fat-soluble vitamin, is responsible for bone mineralization and can help prevent painful muscle spasms caused by faulty calcium absorption. Unlike most essential vitamins, vitamin D is not abundant in foods. Healthy children and adults can attain most of the vitamin D they need through sun exposure or supplements.
About Vitamin D
Skin produces vitamin D when hit by ultraviolet sunlight. It is not unusual for people living closer the equator to have higher vitamin D levels compared to those who live closer to the poles. Vitamin D is a fat-soluble vitamin, meaning the body can store it in the liver and fatty tissues. The body also eliminates fat-soluble vitamins more slowly than water-soluble vitamins, which it must replenish regularly. Typically, there is less risk of vitamin deficiency with fat-soluble vitamins since they store in the body. Vitamin D, however, is an anomaly. The fact that the vitamin is not abundantly available in foods and that people avoid sunlight are to blame for increasing deficiency levels in the United States, according to a 2004 article published by Boston.com.
Vitamin D Block
In 2009, "Scientific American" reported that vitamin D deficiency affects three out of four teens and adults in America. One of the biggest problems is that in the past several years, experts have been driving home the dangers of sunlight. While slathering sunscreen on your skin dramatically reduces your chances of developing skin cancer, a sun block with an SPF of 15 cuts your skin's ability to produce vitamin D by 99 percent, according to research by Adit Ginde, a University of Colorado School of Medicine assistant professor who co-authored a vitamin D study in 2009.
Risks
There is a greater risk for vitamin toxicity in fat-soluble vitamins that the body can store. If you get your vitamin D mostly through direct sunlight or fortified foods, the risk is relatively nonexistent. If you take vitamin D supplements, there is still little chance you will develop a toxic reaction unless you go beyond the recommended daily allowance. The RDA, indicated by the Institute of Medicine, is 600 international units for teens and adults, and 800 IU for seniors over age 50. While the current RDA of vitamin D is relatively new -- the Institute of Medicine raised the requirements in 2010 -- some studies, according to a 2010 article published by "The New York Times," are investigating the effects of vitamin D supplementation at levels of 1,500 to 2,000 IUs a day.
How to Identify Deficiency
The only way to know for sure if your body does not have adequate stores of the sunshine vitamin is through a blood test. If you get less than 15 to 20 minutes of direct sunlight a day while not wearing sunscreen, if you do not eat fortified foods like cereal, eggs, milk and orange juice, or you do not take a vitamin D supplement or multi-vitamin, consider talking to your doctor about having your blood tested.
References
- Office of Dietary Supplements: Vitamin D
- U.S. News & World Report: Americans Fall Short on their Vitamin D; March 2009
- Boston.com: Vitamin D Deficiency Tied to Host of Dangers
- Scientific American: Vitamin D Deficiency Soars in the U.S.; March 2009
- The Washington Post: Vitamin D Deficiency Called Major Health Risk; May 2004
- Mayo Clinic: Vitamin D: New Recommendations Released; Jennifer Nelson, M.S.; December 2010
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