Boosting Vitamin D levels in deficient asthmatics could help manage asthma flare-ups, Israeli researchers have found.
"Vitamin D has significant immunomodulatory effects and believed to have an effect on asthma - an immunologically mediated disease," said Dr Ronit Confino-Cohen from Tel Aviv University's Sackler Faculty of Medicine.
Dr Confino-Cohen and her team analysed the medical records of nearly four million members of Clalit Health Services, Israel's largest health care provider.
The Vitamin D levels of 307,900 people were measured between 2008 and 2012.
Of some 21,000 asthma patients in Israel studied, those with a Vitamin D deficiency were 25 percent more likely than other asthmatics to have had at least one flare-up in the recent past.
"The results add more evidence to the link between Vitamin D and asthma, suggesting beneficial effects of Vitamin D on asthma exacerbations,a Dr Confino-Cohen added.
While most of the Vitamin D in people's bodies comes from exposure to the sun, dermatologists recommend obtaining the ingredient from other sources - fish, eggs, cod liver oil, fortified milk, or a dietary supplement - due to the dangers of overexposure to the sun.
Based on the findings, the researchers recommend that people whose asthma cannot be controlled with existing treatments have their Vitamin D levels tested.
The paper appeared in the journal Allergy.