Taking vitamin D supplements could significantly reduce the risk of severe asthma attacks for some patients, health experts have found.
An investigation involving nine trials with more than 1,000 people found that asthma patients who suffer from severe attacks, or exacerbations, were at a lower risk of an attack if they took regular doses of the vitamin.
They were also less likely to need treatment with steroid tablets and less likely to need hospital treatment.
The researchers are hopeful the findings could pave the way for new treatment options for the 300 million people living with the chronic respiratory disease worldwide.
The trials were conducted by Cochrane, a not-for-profit network of health professionals, and found there were no side effects to taking the supplements.
However, they also found that vitamin D supplements did not improve lung function or day-to-day asthma symptoms in patients, either.
Speaking at a review of the research at London’s Science Media Centre on Monday, lead research author Professor Adrian Martineau said: “Asthma is a rising problem in the UK, with one out of 11 people receiving treatment for it every day.
“Vitamin D, or the sunshine vitamin, as well as enhancing bone development, helps the development of at least 35 other tissues and white blood cells. This can boost immunity against other illnesses and dampen down inflammation.”
The researchers found vitamin D may help prevent respiratory infections, such as the common cold, which can lead to exacerbations in patients.
During the studies, the patients, from a range of ethnic backgrounds, were given different dosages over six to 12-month periods.
Dosages ranged from one to 2,000 units (the equivalent of 50 micrograms) per day - five times the 400-unit dosage recently recommended by Public Health England for all people, with or without asthma.
According to PA, Prof Martineau added: “While the vitamin supplements reduced the number of attacks needing hospital treatment from 6% to 3%, one size may not fit all.
“We don’t know whether these heightened dosages will benefit all asthma patients or just those who already have low levels of vitamin D. Also, about three quarters of asthma patients do not suffer from exacerbations, and we need to do further trials to discover whether the supplements can benefit other groups.”
Commenting on the findings, GP Dr Rebecca Normansell said: “We would recommend anybody to take the simple blood test to determine their vitamin D levels, and to talk to a GP or pharmacist for advice.”
Prof Martineau added: “We would not encourage any asthma patients to replace their regular medication with vitamin D supplements, but to consider taking them in addition to it.”
Dr Imran Rafi, chair of clinical innovation and research at the Royal College of GPs, shared his support for the research and the impact that further investigation could have for treating asthma.
He said: “More work still needs to be done in gathering the evidence, particularly around effectiveness for young people and children – especially as it currently affects as many as one in 11 children.
“It is still too early to make general recommendations on prescribing vitamin D to patients with asthma, but we look forward to seeing the results of further rigorous clinical trials both in adults and children so that we gain a better understanding of this potential method of treatment.”