Vitamin D         

Essential for

the absorption and use of calcium and phosphorus, which are vital for functions such as the development of bones and teeth
healthy nervous and immune systems
regulation of some hormones
normal cell growth and maturation

Absorption and metabolism

Vitamin D requires fat for absorption. It is also made in the skin.

Deficiency

Deficiency in children leads to rickets in which bones lose calcium and become soft and curved. In adults, symptoms include bone pain and tenderness, and muscle weakness. Deficiency may also increase the risk of osteoporosis, arthritis and cancer.

Sources

Good sources include fortified milk, oily fish, liver and eggs.

Daily recommended dietary intakes

Men                        200 IU

(over 50)                400 IU

(over 70)                600 IU

Women                  200 IU

(over 50)                 400 IU

(over 70)                600 IU

Pregnancy             200 IU

Lactation                200 IU

Toxic effects of excess intake

These include symptoms of unusual thirst, sore eyes, itching skin, vomiting, diarrhea, and eventually, calcium deposits in the blood vessels, lungs and kidney.

Interactions

Cholestyramine, anticonvulsants, alcohol and mineral oil interfere with the action of vitamin D.

Therapeutic uses of supplements

Supplements have been used to treat osteoporosis and osteoarthritis in elderly people. Synthetic vitamin D analogues are used to treat psoriasis.

Vitamin D Categories:

Vitamin D
Vitamin D health
Vitamin D absorption
Vitamin D deficiency
Vitamin D sources
Vitamin D recommended daily
Vitamin D overdose
Vitamin D supplements
Vitamin D interactions

Other Vitamins:

Vitamin A
Carotenes
Beta carotene
Lycopene
Lutein
Thiamin
Riboflavin
Niacin
Vitamin B6
Folate
Vitamin B12
Biotin
Pantothenic acid
Vitamin C
Vitamin D
Vitamin E
Vitamin K