Introduction
Vitamin D is essential for strong bones. It may also help prevent some cancers and even heart disease.
It is difficult for most people to get enough vitamin D from food (e.g. fortified milk, fatty fish), so the best sources are sun exposure and supplements.
The recommended amount of vitamin D for adults ranges from 400 to 600 IU a day. However, vitamin D experts say more may be better as much as 800 to 1,000 IU a day.
While it is important not to overexpose your skin to the sun, a little is good health insurance say experts. For the average light-skinned person, 10-15 minutes of sun exposure (without sunscreen) at least three or four days a week should be enough. Ater this, apply some sunscreen. If you have dark skin you will need more exposure.
A sunscreen with an SPF of 8 block 95% of the skin's ability to make vitamin D and an SPF of 15 blocks it by 99%.
During North American winters it is impossible to get enough vitamin D from the sun. That is when many people may need to take supplements or a quality cod liver oil.
Who needs more vitamin D?
People likely to be deficient in vitamin D are the elderly; dark-skinned people; obese people; people who never expose their skin to the sun; infants who breast-feed for more than about six months; North Americnas and Europeans; just about everyone who cannot spend time in the sun most months of the year.
Disclaimer: This information is not intended be a substitute for professional medical advice. It is provided for educational purposes only. You assume full responsibility for how you choose to use this information.
Sources: National Osteoporosis Foundation; Reinhold Vieth and Dr. Michael Holick, vitamin D researchers.