The Effect of Combining Fish Oil and Vitamin C on Hyperpnea-Induced Bronchoconstriction in Asthmatic Adults
Sally K. Head Medicine & Science in Sports & Exercise Volume 45, May 2013, Supplement 1 5S, p 218
Asthma is a multi-faceted disease that often includes exercise-induced bronchoconstriction (EIB). Previous research has demonstrated that individual nutritional supplements, such as fish oil and vitamin C, alleviate EIB. Hyperpnea-induced bronchoconstriction (HIB) has been shown to reliably detect EIB.
PURPOSE: To determine whether the combination of fish oil and vitamin C supplementation offers increased protection against HIB over either one alone.
METHODS: Fourteen subjects (18-29 yrs; 8 M, 6 F) with asthma and HIB participated in a randomized, double-blind, parallel group trial consisting of two treatment periods in which subjects first received either active fish oil (Fish Oil Group, n = 7) or vitamin C supplements (Vitamin C Group, n = 7) every day for 3 weeks. After a 2-week washout period, all subjects received both active fish oil and vitamin C for 3 weeks. Subjects visited the laboratory following an initial 2-week run-in phase and after each supplementation phase for a total of three visits.
Bronchoprovocation was elicited with eucapnic voluntary hyperventilation (EVH), a surrogate exercise challenge involving rapid breathing. Pulmonary function and fraction of exhaled nitric oxide (FENO) were measured pre- and post-EVH.
RESULTS: Fourteen subjects completed the trial. One subject, whose post-EVH forced expiratory volume in one second (FEV1) progressively worsened during the study, was deemed a “nonresponder” and was excluded from further data analysis. The two groups of subjects were analyzed separately. For the primary outcome of maximum percent change in post-EVH FEV1, the Fish Oil Group (n = 6) significantly improved (p < 0.016) with fish oil (9.94 ± 1.90%), but not with the combination treatment (10.19 ± 3.35%), as compared to pre-supplementation (17.29 ±
1.98%). The Vitamin C Group (n = 7) did not show a significant change (p > 0.016) with either vitamin C (18.03 ± 7.05%) or combination treatment (8.64 ± 2.14%) as compared to presupplementation (23.48 ± 4.50%).
CONCLUSIONS: Previous research has shown that either fish oil or vitamin C can reduce bronchoconstriction and airway inflammation on their own. The variable responses obtained in this study suggest that for subjects not reaping the full benefits from either supplement alone, a combination of fish oil and vitamin C may be more effective.