Vitamin D is a fat-soluble vitamin that is used by the body in
the absorption of calcium. Vitamin D promotes the body's absorption of
calcium, which is essential for the normal development and maintenance
of healthy teeth and bones. Calcium is also important to nerve cells,
including the brain. Vitamin D also helps maintain adequate blood levels
of calcium and phosphorus.
A vitamin D deficiency can lead to osteoporosis in adults or rickets
in children. Excessive doses of vitamin D can result in increased calcium
absorption from the intestinal tract. This may cause increased calcium
resorption from the bones, leading to elevated levels of calcium in the
blood. Elevated blood calcium may then cause calcium deposition in soft
tissues such as the heart and lungs. This can reduce their ability to
function.
Vitamin D is also known as the "sunshine vitamin" because the body manufactures
the vitamin after being exposed to sunshine. Ten to 15 minutes of sunshine
3 times weekly is adequate to produce the body's requirement of vitamin
D.
Food Sources: Cheese, Butter, Cream, Fortified milk (all milk in the
U.S. is fortified with vitamin D), Fish, Oysters, Fortified cereals, Margarine.
The current recommended intake of vitamin D is 5 micrograms up to age
50, 10 micrograms between the ages of 51 and 70, and 15 micrograms after
age 70. Very few foods naturally contain vitamin D. Good sources include
dairy products and breakfast cereals (which are fortified with vitamin
D), and fatty fish such as salmon and tuna. For most people, the best
way to get the recommended daily intake is by taking a multivitamin.
