title: Effects of cysteine donor supplementation on exercise-induced bronchoconstriction.
abstract: OBJECTIVE
  Reactive oxygen/nitrogen species (ROS/RNS) in resident airway cells may be important in bronchoconstriction following exercise. Glutathione (GSH) is a major lung antioxidant and could influence pathological outcomes in individuals with exercise-induced bronchoconstriction (EIB). This study examined the effects of supplementation with undenatured whey protein (UWP) in subjects exhibiting airway narrowing following eucapnic voluntary hyperventilation (EVH), a surrogate challenge for diagnosis of EIB. UWP is a cysteine donor that augments GSH production.
  
  
  METHODS
  In a randomized, double-blind, placebo-controlled study, 18 EIB-positive subjects (age: 25.2 +/- 9.01 yr; weight: 77.3 +/- 18.92 kg; height: 1.7 +/- 0.09 m) with post-EVH falls of > or =10% in FEV1 received 30 g UWP (TX) or casein placebo (PL)/d. Subjects performed 6-min EVH challenges before and after 4 and 8 wk of supplementation. Exhaled nitric oxide (eNO) was measured serially before spirometry and at 1-wk intervals. Spirometry was performed pre- and 5, 10, and 15 min postchallenge.
  
  
  RESULTS
  Subjects exhibited significant mean improvement in postchallenge falls in FEV(1) from 0 wk (-22.6 +/- 12.22%) with TX at 4 (-18.9 +/- 12.89%, P < 0.05) and 8 wk (-16.98 +/- 11.61%, P < 0.05) and significant mean reduction in post-EVH peak falls in FEF(25-75) from 0 wk (-40.6 +/- 15.28%) with TX at 4 (-33.1 +/- 17.11%, P < 0.01) and 8 (-29.7 +/- 17.42%, P < 0.05) wk. No changes in FEV(1) or FEF(25-75) were observed in the PL group at any time point. Mean eNO for PL and TX groups at 0, 4, and 8 wk (46.8 +/- 31.33, 46.5 +/- 35.73, 49.3 +/- 37.12 vs 35.2 +/- 26.87, 29.1 +/- 17.26, 34.7 +/- 21.11 ppb, respectively) was not significantly different.
  
  
  CONCLUSIONS
  UWP may augment pulmonary antioxidant capacity and be therapeutically beneficial in individuals exhibiting EIB, as postchallenge pulmonary function improved with supplementation. The lack of significant change in eNO suggests that the pulmonary function improvements from UWP supplementation are independent of eNO.
authors.affiliation: Human Performance Laboratory, Marywood University, Scranton, PA 18509, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Baumann
authors.forename: Kenneth W
authors.initials: KW
authors.lastname: Rundell
authors.forename: Tina M
authors.initials: TM
authors.lastname: Evans
authors.forename: Alan M
authors.initials: AM
authors.lastname: Levine
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D001250:Asthma, Exercise-Induced / Q000178:diet therapy* / Q000378:metabolism / Q000503:physiopathology; D001944:Breath Tests; D003545:Cysteine / Q000008:administration & dosage*; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008168:Lung / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008894:Milk Proteins / Q000008:administration & dosage*; D009569:Nitric Oxide / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D012129:Respiratory Function Tests; D016896:Treatment Outcome; D000067816:Whey Proteins
chemical_list: D000975:Antioxidants; D008894:Milk Proteins; D000067816:Whey Proteins; D009569:Nitric Oxide; D003545:Cysteine