Adding a vitamin D supplement on top of normal medication could lower severity of asthma symptoms, suggests a new review in The Lancet.

Researchers found that people with asthma who took vitamin D supplements alongside their usual medication were 50 percent less likely to visit the emergency department or require hospital admission as a result of an asthma attack.

What is more, the researchers found that vitamin D supplementation was linked to a reduction in the need for steroid injections or tablets following an asthma attack.