Need a Supplement?
If you live in an area with little sunlight during parts of the year, a vitamin D supplement may be recommended. Others who may have a particular need for vitamin D supplements include:
- Dark-skinned people, who synthesize less vitamin D from sunlight than light-skinned people
- Children (especially infants who are breastfed exclusively) and adolescents, women who are pregnant or breastfeeding
- People who have liver or kidney disease or a disorder that hinders vitamin D absorption, such as Crohn's disease or cystic fibrosis
- Those who have undergone gastric bypass or take certain medications, such as corticosteroids
- If you are concerned about your vitamin D intake, talk to your doctor. You can find out if you have a deficiency with a simple blood test.
- Many multivitamins include vitamin D, and so do many calcium supplements. You may consider taking more than the current recommendation of vitamin D, but be careful about overdoing it. Expert opinions on the benefits and risks of higher intake from supplements are mixed. Studies are underway, but for now the U.S. government warns that consuming more than 2,000 IU a day from supplements and food over a long period can be toxic. Our bodies store vitamin D in the liver and fat, so it can accumulate and be used as needed.
- The bottom line? In general, spending a few minutes outside every day during the spring and summer, even when it's cloudy, is unlikely to do harm and may improve your vitamin D intake. After 5 or 10 minutes, make sure to apply sunscreen liberally to exposed skin areas (many people put on too little), and even when you do, don't bake. It's also wise to avoid the sun's strong midday rays. Still, it's nice to know that spending time outside on sunny days, which feels so good, might actually be good for you—if done in moderation.
Reviewed by Timothy Yarboro, M.D.