Also Known as:   Cholecalciferol

Vitamin D Facts
Vitamin D (Cholecalciferol) is a fat soluble vitamin often referred to as the sunshine vitamin because the ultraviolet B rays of the sun cause skin oils to produce this vitamin. Light-skinned people get the RDA of Vitamin D with 30 minutes of sunlight exposure twice a week, and darker-skinned people require longer exposures for the light to penetrate the skin. Excessive exposure will not result in an overdose of Vitamin D, because the body simply stops production and conversion of this vitamin when it reaches what it needs. Since the body's ability to manufacture Vitamin D declines with age, older people (and people who don't go outside much) may become deficient in this vitamin. Vitamin D's importance is its role of making calcium and phosphorus available for the body to use.

How Vitamin D Works
Vitamin D regulates the blood levels of calcium and phosphorus, by increasing the absorption of these minerals and by promoting them into the bones. Vitamin D does this by stimulating DNA to produce transport proteins, which bind to the calcium and phosphorus and increase absorption through the small intestine. This stimulating feature is unusual for a vitamin and normally a function of hormones. Vitamin D also stimulates the uptake of these minerals by bone cells. This process is helpful in building strong bones and healthy teeth.

Possible Benefits

• Helps prevent osterporosis
• Promotes healthy bones and strong teeth
• Helps absorption of the minerals calcium and phosphorus
• Prevents rickets in children and osteomalacia in adults
• May help prevent colon, breast, and prostate cancer
• May slow progression of osteoarthritis of the knee

Usage Guidelines
The RDA for Vitamin D is 400 IU a day (200 IU for children, 600 IU for over age 70). Vitamin D is the most toxic of all vitamins, therefore supplement doses 2 times the RDA for children and 10 times the RDA for adults can produce Vitamin D toxicity. Symptoms may include constipation or diarrhea, headache, appetite loss, nausea, vomiting, irregular heartbeat, and fatigue. Excess Vitamin D in the blood causes calcium to accumulate in the soft tissues of the heart, kidney, and brain, possibly resulting in seizures, disorientation, joint pain, and other problems. A deficiency of Vitamin D can lead to a disease called rickets (in children) or osteomalacia (in adults), which causes soft, fragile bones that are porous and break easily. Other deficiency symptons include diarrhea, insomnia, nervousness, and muscle twitches.

Some Natural Sources
Sunlight, fortified milk, salmon, tuna, shrimp, herring, beef and chicken liver, egg yolk, and fortified cereals