British researchers have found that asthmatics taking vitamin D supplements have a lower risk of suffering a serious asthma attack.

Asthmatics who take vitamin D supplements could halve their chances of winding up in hospital being treated for a serious asthma attack.

British researchers reviewed data from 955 people, mainly adults with mild-to-moderate asthma, involved in seven trials that tested the use of oral vitamin D supplements.

Use of the supplements lead to a 50 per cent drop in the number of people being admitted to a hospital emergency department because of an asthma attack, the study published in The Lancet Respiratory Medicine journal on Thursday said.

There was also a 30 per cent slide in the number of asthmatics needing to be treated with steroids, the researchers from Queen Mary University of London found.

The supplements were found to be particularly beneficial for people who had low levels of vitamin D.

"These results add to the ever-growing body of evidence that vitamin D can support immune function as well as bone health," lead researcher Professor Adrian Martineau said.

"Vitamin D is safe to take and relatively inexpensive so supplementation represents a potentially cost-effective strategy to reduce this problem."

About one-in-nine Australians have asthma, a long-term lung condition that makes the airways in the lungs particularly sensitive and can cause breathlessness, coughing and wheezing.

Asthma Australia chief executive Michele Goldman says while the findings are encouraging as they suggest vitamin D could be another possible way of managing asthma but people should not ditch their preventer medication.

"This could be an effective way to manage asthma in addition to taking your regular preventer medication but it should in no means ....be taken in place of the preventer medication," Mrs Goldman told AAP.

"Preventer medication remains the beset way to treat underlying inflammation in the airway."