If you have asthma, a vitamin D supplement, taken along with standard medication, may help prevent attacks, according to a new Cochrane review, which looked at nine clinical trials involving children or adults, most with mild to moderate disease.
It found not only that people who took the supplements had fewer asthma attacks than those taking a placebo, but also that they were one-third less likely to have an attack requiring steroid medication, and two-thirds less likely to have an attack requiring a trip to the hospital.
However, vitamin D was not associated with improved lung function or day-to-day symptoms. It’s not known what dose is optimal (dosage ranged from 400 to 4,000 IU a day, or 60,000 IU a month, in the studies) nor how baseline vitamin D status affected the results. Moreover, the benefits were seen mainly in adults, so more research is needed, particularly involving children with asthma.
Also see Vitamin D: How Much Do You Know? for a quiz about the sunshine vitamin.