Vitamin D is also known as cholecalciferol, calciferol or the "sunshine vitamin". The body produces Vitamin D when the sun's ultraviolet rays shine on it - only a few minutes a day is enough to meet the average person's requirements. Some animal-based dietary sources are also available.
Natural Food Sources
Cod-liver oil, egg yolk, halibut-liver oil, herring, liver, mackerel, salmon, sardines, tuna, vitamin D fortified milk.
Vitamin D helps the body absorb calcium and phosphorous from the small intestine. It is essential for the growth and maintenance of bones and teeth and can boost your immune system. People who get sufficient vitamin D are less likely to get colon cancer and research suggests it may help treat irritable bowel diseases.
Severe vitamin D deficiency can lead to rickets, a childhood disease that makes bones soft and pliable. Osteomalacia is the adult form of rickets. Deep bone pain and numerous cavities are other symptoms. Children and seniors who live in sun-deprived areas may need vitamin D supplements.
If more than 2000 IU of vitamin D is taken daily, kidney stones, weight loss, irregular heartbeat, diarrhea, extreme thirst, high blood pressure and calcification of tissue may result.
Dietary Reference Intake
5-10 mcg (older adults need 15 mcg)