How does your body naturally produce vitamin D?

Dr. Michael Roizen, MD
Internal Medicine
Production of vitamin D is a three-stage process. In the first stage, the body takes in food that contains a kind of cholesterol that is a precursor to vitamin D. Our bodies cannot use this form of the vitamin without converting it to another form. Only a few foods, such as cod liver oil and certain fatty fishes (tuna, salmon, sardines, oysters, mackerel, and herring) naturally contain vitamin D in the form that can be used by the body.

For the second stage of the conversion, we need sun. The energy of the sun's radiation is necessary to create the right chemical reaction that turns the precursor cholesterols into the form of vitamin D the body can use.

In the final stage of the process, the liver and kidneys convert that vitamin D into yet another form of the vitamin -- vitamin D3, the active form of the vitamin that our bodies can use. You need just 10 to 20 minutes of sunlight a day to ensure that your body is producing enough vitamin D.

After we reach our seventies, the precursor to vitamin D generally found in skin diminishes three- or four-fold, making it increasingly difficult for us to produce vitamin D naturally.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Most people get their vitamin D by exposing their bodies to the sun's rays. It typically takes at most 30 minutes of exposure twice a week to synthesize all of the vitamin D you need. You should keep in mind, however, that staying in the sun for too long could cause skin damage and put you at greater risk for developing a skin disorder or disease.

Use a sunscreen and wear protective clothing to safeguard your skin from the sun's harmful rays.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.