New research shows that people with asthma who have low levels of vitamin D have worse lung function and poorer response to treatment.

Lead researcher, Dr E Rand Sutherland said, “Our findings suggest that low vitamin D levels are associated with worse asthma.”

In the study, 54 asthma patients had their lung function, airway hyper-responsiveness, response to steroids and vitamin D levels measured. For patients with blood levels below 30 nanograms per milliliter, the critical symptom of airway hyper-responsiveness almost doubled! In addition, low vitamin D was linked with worse response to steroids and higher levels of TNF-alpha. TNF-alpha is a cytokine that promotes inflammation in the body; it is implicated in the inflammation of the airways of asthma patients.

Being overweight was linked to the lowest levels of vitamin D. Given the association of asthma with obesity, it is possible that vitamin D levels are behind the relationship.

Dietary sources of vitamin D include fatty fish and fish oils like cod liver oil. The best source of vitamin D is sunlight. Exposure of bare skin to direct sunlight for even a few minutes a day can help to improve vitamin D levels.

Sources: Business Week; BeAllergyWise