title: Manipulating antioxidant intake in asthma: a randomized controlled trial.
abstract: BACKGROUND
  Antioxidant-rich diets are associated with reduced asthma prevalence in epidemiologic studies. We previously showed that short-term manipulation of antioxidant defenses leads to changes in asthma outcomes.
  
  
  OBJECTIVE
  The objective was to investigate the effects of a high-antioxidant diet compared with those of a low-antioxidant diet, with or without lycopene supplementation, in asthma.
  
  
  METHODS
  Asthmatic adults (n = 137) were randomly assigned to a high-antioxidant diet (5 servings of vegetables and 2 servings of fruit daily; n = 46) or a low-antioxidant diet (≤2 servings of vegetables and 1 serving of fruit daily; n = 91) for 14 d and then commenced a parallel, randomized, controlled supplementation trial. Subjects who consumed the high-antioxidant diet received placebo. Subjects who consumed the low-antioxidant diet received placebo or tomato extract (45 mg lycopene/d). The intervention continued until week 14 or until an exacerbation occurred.
  
  
  RESULTS
  After 14 d, subjects consuming the low-antioxidant diet had a lower percentage predicted forced expiratory volume in 1 s and percentage predicted forced vital capacity than did those consuming the high-antioxidant diet. Subjects in the low-antioxidant diet group had increased plasma C-reactive protein at week 14. At the end of the trial, time to exacerbation was greater in the high-antioxidant than in the low-antioxidant diet group, and the low-antioxidant diet group was 2.26 (95% CI: 1.04, 4.91; P = 0.039) times as likely to exacerbate. Of the subjects in the low-antioxidant diet group, no difference in airway or systemic inflammation or clinical outcomes was observed between the groups that consumed the tomato extract and those who consumed placebo.
  
  
  CONCLUSIONS
  Modifying the dietary intake of carotenoids alters clinical asthma outcomes. Improvements were evident only after increased fruit and vegetable intake, which suggests that whole-food interventions are most effective. This trial was registered at http://www.actr.org.au as ACTRN012606000286549.
authors.affiliation: Centre for Asthma and Respiratory Diseases, University of Newcastle, New South Wales, Australia. lisa.wood@newcastle.edu
authors.forename: Lisa G
authors.initials: LG
authors.lastname: Wood
authors.forename: Manohar L
authors.initials: ML
authors.lastname: Garg
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Smart
authors.forename: Hayley A
authors.initials: HA
authors.lastname: Scott
authors.forename: Daniel
authors.initials: D
authors.lastname: Barker
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gibson
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D001249:Asthma / Q000097:blood / Q000178:diet therapy* / Q000276:immunology / Q000503:physiopathology; D002097:C-Reactive Protein / Q000032:analysis; D002338:Carotenoids / Q000009:adverse effects / Q000032:analysis / Q000627:therapeutic use; D004032:Diet / Q000009:adverse effects; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D005260:Female; D005638:Fruit / Q000009:adverse effects / Q000737:chemistry; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000009:adverse effects / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D010352:Patient Dropouts; D010936:Plant Extracts / Q000009:adverse effects / Q000737:chemistry / Q000627:therapeutic use; D012137:Respiratory System / Q000503:physiopathology; D014675:Vegetables / Q000009:adverse effects / Q000737:chemistry
chemical_list: D000975:Antioxidants; D018836:Inflammation Mediators; D010936:Plant Extracts; D002338:Carotenoids; D002097:C-Reactive Protein; D000077276:Lycopene