Vitamin D helps your body absorb calcium, which makes it a key component in building sturdy bones. It also supports muscles and the immune system, and many people have questions about how to get enough.
How much you need
Daily recommended amounts depend on age. Adults 19 to 70 need 15 micrograms (600 IU), adults 71 and older need 20 micrograms (800 IU), and infants need 10 micrograms (400 IU). Breastfed infants should receive a daily supplement. Your needs can differ, so ask a health care provider before you start taking one.
Where it comes from
- Food: very few foods contain vitamin D naturally. Egg yolks, saltwater fish and liver do, and most dietary intake in the United States comes from fortified foods such as milk, many breakfast cereals, some yogurts and some orange juice. Cheese and ice cream usually are not fortified.
- Sunlight: your skin produces it after unprotected exposure to the sun. Clouds, smog, age and darker skin lower the amount produced, and skin does not make it through window glass.
- Supplements: they come as D2 and D3, and both raise blood levels. Vitamin D is fat soluble, so taking it with a meal that has some fat helps absorption.
Sun and skin safety
Health experts advise limiting time in the sun and using sunscreen of SPF 15 or higher, even though sunscreen reduces vitamin D production a little. Vitamin D should not be a reason for skipping sun protection.
Checking your level
A blood test can tell you where you stand. Blood levels from 50 nmol/L (about 20 ng/mL) upward are considered adequate for most people. Under 30 nmol/L is too low, and over 125 nmol/L may cause problems. Nearly one in four people in the United States has a level that is too low or marginal.
Who may need extra attention
Older adults, people with limited sun exposure, people with darker skin and those whose bodies do not absorb fat well may have a harder time reaching adequate levels. Taking more than recommended is not harmless, so talk with your provider before supplementing.
Filed under: Washington DC Health News
