Influence of Mediterranean Diet on Asthma Symptoms, Lung Function, and Systemic Inflammation: A Randomized Controlled Trial

Abstract

Objective. The rapidly increasing prevalence of asthma in developed countries suggests an environmental cause. The benefits of Mediterranean diet (MD) in cardiovascular disease have been tentatively attributed to its anti-inflammatory properties. Asthma is an inflammatory disease and MD is associated with reduced asthma risk in epidemiological studies, but there are no reported interventional studies of MD in asthma. Methods. In this 12-week open-label randomized trial, 38 adults with symptomatic asthma were allocated to high-intervention (HI), low-intervention (LI), and control groups. The first two groups were encouraged to adopt an MD and received multiple consultation sessions with a nutritionist, written advice, and vouchers for the purchase of appropriate foods. Food frequency questionnaires, asthma control questionnaires, asthma-related quality of life questionnaires (AQLQs), and spirometry were completed at the beginning and at the end of the study. Results: The MDt score increased in the HI group (p < .001), indicating successful alteration of dietary behavior. Statistically, nonsignificant improvements were seen in spirometry and several AQLQ subdomains in the two intervention groups. No changes were seen in the asthma control or in inflammatory markers. Conclusions: The trial intervention has successfully altered the dietary behavior among adults with asthma. Small but consistent improvements were seen in quality of life and spirometry among the intervention group. The use of the MD to treat asthma is feasible and warrants evaluation in a larger study, powered to examine clinical endpoints.

• airways disease
• asthma
• Mediterranean diet

Acknowledgments

This article is dedicated to our close friend and mentor Prof. Peter Black, who died suddenly in January 2010. Peter was instrumental in the conception and design of this study. His death is a huge loss to us personally and to the medical research community. Peter’s research family gratefully acknowledge his lasting contribution to Medicine through his research, teaching, and clinical work. A principled man of humanity and kindness, Peter remains an inspiration to all who were privileged to spend time with him.

Declaration of Interest

The authors report no conflicts of interest.

The study was funded by the Health Research Council of New Zealand. We thank Sanitarium Foods and Heinz Watties for their donations of food for the study.

Notes

1. Diet diaries were completed for 3 days of each inter-visit period, chosen at random.