Protective effect of fish oil supplementation on
exercise-induced bronchoconstriction in asthma
BACKGROUND: Previous research has demonstrated that fish oil
supplementation has a protective effect on exercise-induced bronchoconstriction
(EIB) in elite athletes, which may be attributed to its antiinflammatory
properties. Since EIB in asthma involves proinflammatory mediator release, it is
feasible that fish oil supplementation may reduce the severity of EIB in
asthmatic subjects. STUDY OBJECTIVES: To determine the efficacy of fish oil
supplementation on severity of EIB in subjects with asthma. DESIGN: Randomized,
double-blind, crossover study. SETTING: Lung function and exercise testing in a
university research laboratory. Patients and measurements: Sixteen asthmatic
patients with documented EIB entered the study on their normal diet and then
received either fish oil capsules containing 3.2 g of eicosapentaenoic acid and
2.0 g of docohexaenoic acid (fish oil diet, n = 8) or placebo capsules (placebo
diet, n = 8) daily for 3 weeks. At the beginning of the study (normal diet) and
at the end of each treatment phase, the following pre-exercise and postexercise
measures were assessed: (1) pulmonary function; (2) induced sputum differential
cell count percentage and proinflammatory eicosanoid metabolite (leukotriene C4
[LTC4]-leukotriene E4 [LTE4] and prostaglandin D2 [PGD2]) and cytokine
(interleukin [IL]-1beta and tumor necrosis factor [TNF]-alpha) concentrations;
and (3) eicosanoid metabolites leukotriene B4 (LTB4) and leukotriene B5 (LTB(5))
generation from activated polymorphonuclear leukocytes (PMNLs). RESULTS: On the
normal and placebo diet, subjects exhibited EIB. However, the fish oil diet
improved pulmonary function to below the diagnostic EIB threshold, with a
concurrent reduction in bronchodilator use. Induced sputum differential cell
count percentage and concentrations of LTC4-LTE4, PGD2, IL-1beta, and TNF-alpha
were significantly reduced before and following exercise on the fish oil diet
compared to the normal and placebo diets. There was a significant reduction in
LTB4 and a significant increase in LTB5 generation from activated PMNLs on the
fish oil diet compared to the normal and placebo diets. CONCLUSION: Our data
suggest that fish oil supplementation may represent a potentially beneficial
nonpharmacologic intervention for asthmatic subjects with EIB. Mickleborough TD,
Lindley MR, Ionescu AA, Fly AD. Chest. 2006 Jan;129(1):39-49.
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*These statements have not been evaluated by the Food & Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
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