Vitamin D Source

Vitamin D is an important nutrient, but many people aren’t getting enough of it. You need vitamin D in order to absorb calcium and build healthy bones. There is also some evidence that vitamin D also plays a role in reducing the risk of certain severe health conditions, like multiple sclerosis and colon cancer.

Unlike other vitamins, your body can make vitamin D on its own, when your skin is exposed to sunlight. Vitamin D is also found in some foods, as well as in vitamin supplements. While low vitamin D levels are relatively common, they are also usually easy to correct with lifestyle or dietary changes, or by taking supplements.

Vitamin D and the Sun

Sunlight is the easiest and most efficient way to get vitamin D. Your body can make all the vitamin D it needs if your skin is exposed to the sun’s UVB radiation in direct sunlight for between 5 and 30 minutes a few times a week.

Inadequate sunlight exposure is a major cause of vitamin D deficiency, and is a particular problem for people who live in northern climates, have dark skin, or keep most or all of their body covered when outside. Sunscreen may also inhibit production of vitamin D.

Vitamin D and Food

Vitamin D is naturally found in certain foods, such as tuna, mackerel, salmon, cod liver oil, egg yolks and beef liver. Milk, juice and margarine may also be fortified with vitamin D. While some foods are good sources of vitamin D, it is very difficult – if not impossible – for a person to get enough vitamin D from food sources alone.

Vitamin D Supplements

Vitamin supplements are another way to get vitamin D. If getting enough vitamin D through sun exposure or diet is difficult, a vitamin deficiency can usually be easily corrected by adding supplements.

Doctors routinely recommend vitamin D supplements for certain groups of people, such as breast-fed infants. If you have certain risk factors or conditions (such as osteoporosis or certain kidney and liver problems) your doctor may also prescribe vitamin D supplements. A blood test can also help your doctor determine if you need more vitamin D.

How Much Vitamin D Do I Need?

Currently, the Institute of Medicine recommends that adults get between 200 and 600 IU of vitamin D per day. Children need about 200 IU per day. However, some experts believe that these recommendations are too low, and that people may need 1,000 IU per day or more for optimum health. More than 2,000 IU of vitamin D per day may result in vitamin D toxicity.


Mayo Clinic Staff. (2009). Vitamin D. Retrieved December 27, 2009 from the Mayo Clinic website:

Merck Home Manual Staff. (n.d.). Vitamin D. Retrieved December 27, 2009 from the Merck website:

National Institutes of Health, Office of Dietary Supplements Staff. (2009). Dietary Supplement Fact Sheet: Vitamin D. Retrieved December 27, 2009 from the National Institutes of Health website: