Nigella sativa Supplementation Improves Asthma Control and Biomarkers: A Randomized, Double-Blind, Placebo-Controlled Trial.

Poor compliance with conventional asthma medications remains a major problem in achieving asthma control. Nigella sativa oil (NSO) is used traditionally for many inflammatory conditions such as asthma. We aimed to investigate the benefits of NSO supplementation on clinical and inflammatory parameters of asthma. NSO capsules 500 mg twice daily for 4 weeks were used as a supplementary treatment in a randomized, double-blind, placebo-controlled trial in asthmatics (clinicaltrials.gov: NCT02407262). The primary outcome was Asthma Control Test score. The secondary outcomes were pulmonary function test, blood eosinophils and total serum Immunoglobulin E. Between 1 June and 30 December 2015, 80 asthmatics were enrolled, with 40 patients in each treatment and placebo groups. After 4 weeks, ten patients had withdrawn from each group. Compared with placebo, NSO group showed a significant improvement in mean Asthma Control Test score 21.1 (standard deviation = 2.6) versus 19.6 (standard deviation = 3.7) (p = 0.044) and a significant reduction in blood eosinophils by -50 (-155 to -1) versus 15 (-60 to 87) cells/μL (p = 0.013). NSO improved forced expiratory volume in 1 second as percentage of predicted value by 4 (-1.25 to 8.75) versus 1 (-2 to 5) but non-significant (p = 0.170). This randomized, double-blind, placebo-controlled trial demonstrated that NSO supplementation improves asthma control with a trend in pulmonary function improvement. This was associated with a remarkable normalization of blood eosinophlia. Future studies should follow asthmatics for longer periods in a multicentre trial.