Vitamin D supplements, in addition to asthma medication for more than six months, could reduce the risk of severe exacerbation by half, reports a recent study.

Researchers found that vitamin D reduces the risk of hospitalization in patients with mild to moderate asthma compared to those who did not take supplements. The number of patients in need of steroid treatment was also found to have decreased from one person every two years to one person every four years.

About 300 million people across the world experience symptoms of asthma, including chest tightness, wheezing, coughing and shortness of breath. Vitamin D has long been associated with asthma so the researchers looked into the efficacy of the supplement on patients with the condition.

For the purpose of the study, the researchers reviewed two trials involving 658 adults and seven trials involving 435 children. All the participants suffered mild to moderate asthma with symptoms at least two days per week. Though all patients were on regular asthma medications, their everyday routine wasn't much affected by the condition.

According to the study findings, with 25 to 30 micrograms of vitamin D supplements a day, the risk of exacerbation was observed to decrease in both children and adults, but the evidence was stronger among adults.

Adrian Martineau, lead author of the review who spoke at London's Science Media Centre, said that vitamin D helps in the development of bone, white blood cells and 35 other tissues. The vitamin also reduces inflammation and enhances immunity against diseases.

However, the researchers noted that it is not clear whether the supplements work only in patients with vitamin D deficiency or any asthma patient.

"While the vitamin supplements reduced the number of attacks needing hospital treatment from 6 per cent to 3 per cent, one size may not fit all," said Martineau.

He added that the study doesn't recommend substitution of asthma pills with supplements but that patients can consider taking them in addition to regular pills.

Dr. Imran Rafi, chair of clinical innovation and research at the Royal College of General Practitioners, said that to be able to prescribe vitamin D supplements for asthma patients further, research involving both children and adults are necessary.

Erika Kennington, head of research for the charity Asthma UK, also said that there are people suffering from different types of asthm, so vitamin D supplements could be helpful in treating few patients and not everyone.

The study was presented at European Respiratory Society meeting in London.

Photo: Alan Levine | Flickr