Vitamin D is required by your body to absorb and utilize calcium, which keeps your bones and teeth strong. A deficiency of vitamin D leads to weakened bones and rickets in children and osteomalacia in adults.
Although sunlight exposure is the main source of vitamin D, the Institute of Medicine has set a daily requirement for dietary vitamin D.Daily Requirements
1 to 50 years of age 5 mcg per day
51 to 70 years of age 10 mcg per day
51 to 50 years of age 15 mcg per day
Research studies indicate that having insufficient levels of vitamin D may be correlated with an increased risk of cancer, multiple sclerosis, diabetes and high blood pressure.
Vitamin D is found naturally in just a few foods such as oily fish, however milk and breakfast cereals are usually fortified with vitamin D. Vitamin D supplementation may be beneficial for many people, especially during the winter or if you avoid sun exposure. Vitamin D supplementation is often recommended for people who take calcium supplements to prevent osteoporosis.
There are two types of vitamin D supplements, either D2, which is also called ergocalciferol or D3, cholecalciferol. Both forms will raise your body's stores of vitamin D, however, cholecalciferol is becoming the preferred form for vitamin D supplements.
Taking vitamin D supplements in large doses for extended periods of time may result in vitamin D toxicity, so the Institute of Medicine determined tolerable upper levels to be 25 mcg per day for infants and 50 mcg per day for the age of 12 months through adulthood. Vitamin D toxicity does not occur from the vitamin D that your body makes when your skin is exposed to the sun.
Sources:
Office of Dietary Supplements. "Dietary Supplement Fact Sheet: Vitamin D." NIH. Updated 08/2007.
Food and Nutrition Board. "Dietary Reference Intakes." Institute of Medicine. Published 2004.
