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Manipulating antioxidant intake in asthma: a randomized controlled trial.
Am J Clin Nutr 2012; 96(3):534-43AJ

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.

DESIGN

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+Show Affiliations

Centre for Asthma and Respiratory Diseases, University of Newcastle, New South Wales, Australia. lisa.wood@newcastle.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Randomized Controlled Trial
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22854412

Citation

Wood, Lisa G., et al. "Manipulating Antioxidant Intake in Asthma: a Randomized Controlled Trial." The American Journal of Clinical Nutrition, vol. 96, no. 3, 2012, pp. 534-43.
Wood LG, Garg ML, Smart JM, et al. Manipulating antioxidant intake in asthma: a randomized controlled trial. Am J Clin Nutr. 2012;96(3):534-43.
Wood, L. G., Garg, M. L., Smart, J. M., Scott, H. A., Barker, D., & Gibson, P. G. (2012). Manipulating antioxidant intake in asthma: a randomized controlled trial. The American Journal of Clinical Nutrition, 96(3), pp. 534-43. doi:10.3945/ajcn.111.032623.
Wood LG, et al. Manipulating Antioxidant Intake in Asthma: a Randomized Controlled Trial. Am J Clin Nutr. 2012;96(3):534-43. PubMed PMID: 22854412.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Manipulating antioxidant intake in asthma: a randomized controlled trial. AU - Wood,Lisa G, AU - Garg,Manohar L, AU - Smart,Joanne M, AU - Scott,Hayley A, AU - Barker,Daniel, AU - Gibson,Peter G, Y1 - 2012/08/01/ PY - 2012/8/3/entrez PY - 2012/8/3/pubmed PY - 2012/10/27/medline SP - 534 EP - 43 JF - The American journal of clinical nutrition JO - Am. J. Clin. Nutr. VL - 96 IS - 3 N2 - 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. DESIGN: 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. SN - 1938-3207 UR - https://www.unboundmedicine.com/medline/citation/22854412/Manipulating_antioxidant_intake_in_asthma:_a_randomized_controlled_trial_ L2 - https://academic.oup.com/ajcn/article-lookup/doi/10.3945/ajcn.111.032623 DB - PRIME DP - Unbound Medicine ER -