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Comparable reductions in hyperpnoea-induced bronchoconstriction and markers of airway inflammation after supplementation with 6·2 and 3·1 g/d of long-chain n-3 PUFA in adults with asthma.
Williams, NC, Hunter, KA, Shaw, DE, Jackson, KG, Sharpe, GR, Johnson, MA
The British journal of nutrition. 2017;(10):1379-1389
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Abstract
Although high dose n-3 PUFA supplementation reduces exercise- and hyperpnoea-induced bronchoconstriction (EIB/HIB), there are concurrent issues with cost, compliance and gastrointestinal discomfort. It is thus pertinent to establish the efficacy of lower n-3 PUFA doses. Eight male adults with asthma and HIB and eight controls without asthma were randomly supplemented with two n-3 PUFA doses (6·2 g/d (3·7 g EPA and 2·5 g DHA) and 3·1 g/d (1·8 g EPA and 1·3 g DHA)) and a placebo, each for 21 d followed by 14 d washout. A eucapnic voluntary hyperpnoea (EVH) challenge was performed before and after treatments. Outcome measures remained unchanged in the control group. In the HIB group, the peak fall in forced expiratory volume in 1 s (FEV1) after EVH at day 0 (-1005 (sd 520) ml, -30 (sd 18) %) was unchanged after placebo. The peak fall in FEV1 was similarly reduced from day 0 to day 21 of 6·2 g/d n-3 PUFA (-1000 (sd 460) ml, -29 (sd 17) % v. -690 (sd 460) ml, -20 (sd 15) %) and 3·1 g/d n-3 PUFA (-970 (sd 480) ml, -28 (sd 18) % v. -700 (sd 420) ml, -21 (sd 15) %) (P<0·001). Baseline fraction of exhaled nitric oxide was reduced by 24 % (P=0·020) and 31 % (P=0·018) after 6·2 and 3·1 g/d n-3 PUFA, respectively. Peak increases in 9α, 11β PGF2 after EVH were reduced by 65 % (P=0·009) and 56 % (P=0·041) after 6·2 and 3·1 g/d n-3 PUFA, respectively. In conclusion, 3·1 g/d n-3 PUFA supplementation attenuated HIB and markers of airway inflammation to a similar extent as a higher dose. Lower doses of n-3 PUFA thus represent a potentially beneficial adjunct treatment for adults with asthma and EIB.
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Vitamin D and omega-3 polyunsaturated fatty acid supplementation in athletes with exercise-induced bronchoconstriction: a pilot study.
Price, OJ, Hull, JH, Howatson, G, Robson-Ansley, P, Ansley, L
Expert review of respiratory medicine. 2015;(3):369-78
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.
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Exercise-induced bronchoconstriction in children: montelukast attenuates the immediate-phase and late-phase responses.
Melo, RE, Solé, D, Naspitz, CK
The Journal of allergy and clinical immunology. 2003;(2):301-7
Abstract
BACKGROUND Montelukast, a leukotriene receptor antagonist, attenuates exercise-induced bronchoconstriction. We and others have shown that there is a late-phase response 3 to 8 hours after exercise in a subset of asthmatic patients. OBJECTIVE We sought to evaluate the protective effect of montelukast on immediate-phase and late-phase responses after exercise challenges. METHODS Twenty-two atopic asthmatic children aged 7 to 16 years with reproducible exercise-induced bronchoconstriction (minimum of 15% decrease of FEV(1) from baseline) were enrolled in this placebo-controlled crossover study. Exercise challenges were performed while breathing cold dry air, and FEV(1) measurements were taken up to 480 minutes after exercise. Patients underwent exercise challenges on a screening day and 1 week after placebo treatment. Subsequently, after a week with no treatment, pulmonary function was assessed after breathing dry cold air (control day). Finally, an exercise challenge was carried out after a week of treatment with montelukast. RESULTS Reproducible late-phase reactions occurred in 5 of 22 patients, which correlated with the extent of the immediate response (P <.05). After 1 week of treatment with montelukast, a significant decrease of immediate responses was observed. Montelukast treatment compared with placebo was associated with a lower mean maximum decrease of FEV(1) (mean +/- SEM: 17.3% +/- 2.4% and 35.1% +/- 2.6%, respectively), decrease of the area above the curve (267.8% +/- 42.7%/min and 868.0% +/- 103.8%/min, respectively), and shorter time for recovery (6.9 +/- 1.1 minutes and 30.9 +/- 4.0 minutes, respectively; P <.05). Treatment with montelukast also abolished late-phase responses. CONCLUSION Once daily treatment with oral montelukast attenuated the immediate-phase response and abolished the late-phase response induced by means of exercise challenge in asthmatic children.
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Fog-induced respiratory responses are attenuated by nedocromil sodium in humans.
Lavorini, F, Fontana, GA, Pantaleo, T, Camiciottoli, G, Castellani, W, Maluccio, NM, Pistolesi, M
American journal of respiratory and critical care medicine. 2001;(5):1117-20
Abstract
Fog inhalation induces cough and bronchoconstriction in patients with asthma, but only cough in normal subjects; whether it also influences the pattern of breathing is unclear. Nedocromil sodium (NCS) inhibits the cough response to inhalation of several pharmacological agents but its effects on fog-induced cough and changes in the pattern of breathing are unknown. We evaluated the effects of no drug, placebo, and 4- and 8-mg NCS administration on the cough threshold and changes in the pattern of breathing during fog inhalation in 14 healthy subjects. Measurements of tidal volume (VT), duration of inspiratory and expiratory times (TI and TE, respectively), total duration of the respiratory cycle (TT), mean inspiratory flow (VT/TI), duty cycle (TI/TT), respiratory frequency (f, 60/TT), and inspiratory minute ventilation (V I) were obtained by inductive plethysmography. Median cough threshold values were unaffected by placebo, but were increased (p < 0.01) by both NCS doses. In no-drug and placebo trials, inhalation of the threshold fog concentration caused increases in both VT/TI and V I (p always < 0.05) due to selective increases (p < 0.01) in VT. These changes were markedly attenuated by both NCS doses administration. Thus, fog induces coughing and increases in VT, VT/ TI, and V I in healthy subjects; NCS possesses antitussive effects and attenuates fog-induced changes in the pattern of breathing, possibly through inhibition of rapidly adapting "irritant" receptors.
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Dietary chloride as a possible determinant of the severity of exercise-induced asthma.
Mickleborough, TD, Gotshall, RW, Kluka, EM, Miller, CW, Cordain, L
European journal of applied physiology. 2001;(5):450-6
Abstract
Dietary sodium chloride (NaCl) has been shown to alter the severity of exercise-induced asthma, but it is not known if the sodium and chloride ions have independent effects in this regard. The hypothesis tested in the present study was that both a low sodium, low chloride diet and a high sodium, low chloride diet would improve post-exercise pulmonary function in subjects with exercise-induced asthma (EIA) compared to a normal NaCl diet (NSD); but that neither of these diets would have an effect on post-exercise pulmonary function in control (non-EIA) subjects. Eight subjects who suffered from EIA and eight subjects who did not (control) took part in a double-blind crossover study. Pre- and post-exercise pulmonary function was assessed after 2 weeks on a NSD, a low NaCl diet (LSD, low sodium, low chloride) or a sodium bicarbonate diet (NaHCO3 diet, high sodium, low chloride). A 1 week washout period occurred between diets. Altering dietary sodium or chloride had no effect on pre-exercise (baseline) pulmonary function in either group or on post-exercise pulmonary function in control subjects. However, both the LSD and the NaHCO3 diet lessened the deterioration in post-exercise pulmonary function in EIA subjects. Comparing results from pre- to post-exercise, forced expiratory volume in 1 s (FEV1) at 15 min post-exercise differed significantly (P < 0.05) between diets [mean (SEM) 7 (4)% on the LSD, 14 (4)% on the NaHCO3 diet, and 19 (2)% on the NSD]. Similar patterns were observed for forced vital capacity (FVC), forced expiratory flow rate at 25%-75% FVC and peak expiratory flow rate. The NaHCO3 diet lessened the deterioration of post-exercise pulmonary function, but not to the extent of LSD. These data suggest that both sodium and chloride contribute to the worsening of EIA symptoms seen after consuming a normal or high NaCl diet.