Monday, February 21, 2011

How much Vitamin-D do you need?

Vitamin D is a vitamin (a substance the body requires in small doses for proper nutrition and function) that is
fat-soluble, meaning that it is dissolved and stored in the fat of your body. Vitamin-D maintains proper levels
of calcium and phosphorus in the blood and together with calcium builds strong bones. The November 9,
2005, issue of JAMA (the Journal of the American Medical Association) contains an article about sufficient
levels of vitamin D for healthy bones.

Sunlight Exposure
Sun exposure for 10 to 15 minutes at least twice a week usually provides adequate amounts of vitamin D.
Certain conditions such as cloud cover, northern climates, pollution, and the winter months may not provide
adequate sunlight exposure. Excess sun exposure causes skin cancer, so you should limit exposure to
sunlight, not use tanning beds, and wear protective clothing and a sunscreen with a sun protection factor
(SPF) of at least 15 when outdoors for longer than 10 to 15 minutes twice a week. Infants should be kept out
of direct sunlight all together.

Vitamin-D Deficiency
When vitamin D levels are low, bones become weak and brittle. In children, vitamin D deficiency causes a
disease called rickets, which results in poorly developed weak bones, delayed growth, immune deficiencies,
and, when severe, seizures. In adults, vitamin D deficiency causes a disease called osteomalacia, which
results in weak bones, fractures, bone pain, and weakness. Low levels of vitamin D may be a factor in
osteoporosis (thin bones).

Who is at risk of developing Vitamin-D deficiency?
• Infants who are exclusively breast-fed or receiving less than about 2 cups a day of vitamin D fortified
formula or milk.
• People who have darker-pigmented skin.
• People with very limited sunlight exposure.
• People with fat malabsorption diseases, such as pancreatitis, cystic fibrosis, celiac disease, and
surgical resection of the bowel.
• People who have liver or kidney disease or enzyme deficiencies.
• People in the northern hemisphere during winter.

How much Vitamin-D do you need?
For infants to adults aged 50 years, the daily adequate intake is 200 international units (IU) of vitamin D. For
adults aged 51 to 70 years, 400 IU is required, and for those older than 70 years, 600 IU is recommended.
Discuss with your doctor the proper vitamin D intake and sun exposure for you and whether you should take
a supplement, especially if you are at risk of developing a deficiency. Too much vitamin D can occur from
taking excess vitamin D supplements and can cause serious problems, such as nausea, vomiting, and
weakness or even confusion and heart rhythm abnormalities.

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