Health Article: Vitamin D Fact Sheet
Vitamin D is a term for several hormones that are stored mainly in the liver and in fat and muscle tissue. Vitamin D is essential for maintaining healthy bone structure because of its role in the absorption and metabolism of calcium. It is easily absorbed during digestion and is excreted from the body very slowly. It is manufactured in the body from a chemical reaction to the ultraviolet radiation in sunlight and is found in a few food sources, including vitamin D-fortified milk, fatty fish, egg yolk and liver. The AI (adequate intake) level is 200 IU (5 mcg) per day for children and most adults, 400 IU (10 mcg) for people over 50, and 600 IU (15 mcg) for those over 70 who do not have sufficient exposure to sunlight. Some experts believe that many people require supplements to achieve the recommended levels.
Deficiencies of Vitamin D
Deficiencies in vitamin D result in rickets in children and osteomalacia in adults. Both diseases are characterized by a softening of the bones caused by low amounts of calcium and phosphorous. Vitamin D deficiency also increases the risk for hip fractures in post-menopausal women, and is associated with a higher risk for breast cancer, especially in older women, and prostate cancer. There has been some concern that under-exposure to sunlight in older people, particularly if they live in northern regions, may put them at risk for low levels of vitamin D. A 1998 study suggests that vitamin D deficiency may be a significant problem in the general US population, even among younger adults. Experts note that adults may need higher daily amounts than the RDA suggests. Exposure to sunlight for about 15 to 20 minutes at mid-morning or mid-afternoon three times a week is also recommended for most people who live in temperate climates.
Toxicity of Vitamin D
Vitamin D is very toxic in high doses. Infants can be severely affected by daily amounts higher than 1000 IU, which can lead to mental and growth retardation, kidney failure and death. In children and adults, daily amounts over 50,000 IU can cause weakness, anorexia, vomiting, diarrhea and mental changes. Prolonged use of megadoses can cause calcification of soft tissue and life-threatening kidney failure. Low-calcium diets and withdrawal from the vitamin can usually reverse the side effects, except for kidney failure.
IMPORTANT NOTE: One of our readers disagreed with the content of this article. It’s important to be well-informed, so I agree with her suggestion that you should investigate this topic further at http://www.vitamindcouncil.org and any other source you deem appropriate. You should never accept just one source when it comes to your health. As a healthcare writer, I see varying opinions every day on a variety of important health-related topics. It’s up to you to do your own research and decide what’s right for your body.
Photo by Steve Woods
We hope you found this vitamin D health article helpful! You might also be interested in these vitamin-related articles:
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- Drugs That Deplete Vitamins and Minerals
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