Vitamin D ‘protects against severe asthma attacks’

“Vitamin D supplements could halve risk of serious asthma attacks,” The Guardian reports. A review of previous data found that vitamin D supplements could have a protective effect against serious asthma attacks when taken alongside normal asthma treatment.

Vitamin D is made in the skin when it’s exposed to sunlight. Many people in the UK have low levels of vitamin D, especially during the winter when sunlight is weak. People with low levels of vitamin D seem to be more likely to have asthma attacks. The researchers wanted to pool data to get a clearer picture of whether vitamin D supplements could help.

Any review of this sort is only as good as the studies fed into it. While the studies were judged to be of a good quality, the reviews’ authors warn that there were “relatively few” studies included; seven in total. But the main conclusions were based on just three studies which mainly involved adults with mild or moderate asthma. This means the results may not apply to people with severe asthma, or to children.

Unfortunately, the review can’t tell us whether everyone with asthma would benefit from taking vitamin D, or only people whose vitamin D levels are low. Also, it doesn’t give us a recommended dose.

Public Health England recently recommended everyone in the UK considers taking a 10microgram dose of vitamin D daily, especially in winter. However doses in some of these asthma studies were much higher.

So it is unclear whether there is such a thing as an optimal dose, and even if there was, what that would be.

Story courtesy of the NHS