Vitamin D and omega-3 polyunsaturated fatty acid supplementation in athletes with exercise-induced bronchoconstriction: a pilot study

Abstract

Objective: The aim of this pilot study was to determine the combined effect of vitamin D and omega-3 polyunsaturated fatty acid (PUFA) supplementation on airway function and inflammation in recreational athletes with exercise-induced bronchoconstriction (EIB). Methods: Ten recreational athletes with EIB participated in a single-blind, placebo-controlled trial over six consecutive weeks. All subjects attended the laboratory on three occasions. Each visit was separated by a period of 3 weeks: visit 1 (usual diet), visit 2 (placebo) and visit 3 (SMARTFISH^® NutriFriend 2000; 30 µg vitamin D3–3000 mg eicosapentaenoic acid, 3000 mg docosahexaenoic acid) consumed once daily for a period of 3 weeks. Venous blood was collected at the beginning of each trial to determine vitamin D status. Spirometry was performed pre- and post-eucapnic voluntary hyperpnoea (EVH). Results: The Maximum fall in FEV1 (ΔFEV₁max) post-EVH was not different between visits (usual diet: −15.9 ± 3.6%, placebo: −16.1 ± 6.1%, vitamin D + omega-3 PUFA: −17.8 ± 7.2%). Serum vitamin D remained unchanged between visits. Conclusion: Vitamin D and omega-3 PUFA supplementation does not attenuate the reduction in lung function post-EVH. This finding should be viewed as preliminary until the results of randomised controlled trials are made available.

Keywords:

• airway dysfunction
• exercise-induced bronchoconstriction
• inflammation
• omega-3 polyunsaturated fatty acids
• vitamin D

Financial & competing interests disclosure

Dietary supplements were provided by SMARTFISH^® Medical Nutrition. All other funding was provided by Northumbria University. The authors have no other relevant affiliations or financial involvement with any organisation or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Key issues

• Vitamin D deficiency has previously been associated with the development and severity of asthma, with low serum vitamin D levels associated with reduced lung function and increased reactivity to exercise in children with exercise-induced bronchoconstriction (EIB).

• Omega-3 polyunsaturated fatty acid (PUFA) supplementation has been shown to attenuate airway inflammation and bronchoconstriction following indirect bronchoprovocation.

• The aim of this pilot study was to determine the combined effect of acute vitamin D and omega-3 PUFA supplementation on airway function in recreational athletes with EIB.

• The combination of vitamin D and omega-3 PUFA supplementation does neither reduce the markers of airway inflammation nor attenuate the reduction in lung function following eucapnic voluntary hyperpnoea.

• Serum vitamin D status does not appear to directly correspond to the severity of bronchoconstriction.

• The inherent variability of a test (i.e., indirect bronchoprovocation) employed to determine changes in lung function should be considered when advocating the efficacy of a treatment intervention to avoid masking or overestimating the proposed therapeutic benefit.

• Further work is required to determine the individual and combined effect of omega-3 PUFA and vitamin D as a non-pharmacological treatment for EIB. The findings of the present study should be viewed as preliminary until the results of randomised controlled trials are made available.

Notes