Vitamin D is required by your body to absorb and utilize calcium, which keeps your bones and teeth strong. A vitamin D deficiency leads to weakened bones and rickets in children and osteomalacia in adults.Although sunlight exposure is the main source, the Institute of Medicine has set a daily requirement for dietary vitamin D.
- Up to age 70: 600 International Units (IUs) per day
- Ages 71 and older: 800 IUs per day
Observational 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 oily fish. It's also added to milk, soy milk and breakfast cereals. Vitamin D supplements may be beneficial for many people, especially during the winter or if you normally avoid sun exposure. Vitamin D is usually added to calcium supplements to increase calcium absorption in order to prevent osteoporosis.
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:
- Ages 1-3: 2500 IUs per day
- Ages 4-8: 3000 IUs per day
- Ages 9 and above: 4,000 IUs per day
"Dietary Supplement Fact Sheet: Vitamin D." National Institutes of Health. Updated 08/2007.
Otten JJ, Hellwig JP, Meyers LD. "Dietary Reference Intakes: The Essential Guide to Nutrient Requirements." IOM, 2006.