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Healthy diet improves lung function in COPD-patients

BARCELONA –

A diet rich in antioxidants may protect against the progression of chronic obstructive pulmonary disease (COPD) and even improve lung function, according to data presented at the 20th Annual Congress of the European Respiratory Society.

The prevalence of COPD is increasing worldwide. The natural course of the disease is a progressive and irreversible airflow obstruction, impaired quality of life and increased mortality, and thus its management is currently considered a major health issue. COPD is characterised by episodic worsening – so-called exacerbations – and increased oxidative stress that may increase airway and systemic inflammation.

It has been hypothesised that balancing oxidative stress might be protective for COPD. Previous studies that investigated the role of dietary interventions against oxidative stress have shown that foods rich in antioxidants may be protective against oxidative stress resulting from smoking or air pollution. Cross-sectional surveys showed that forced expiratory volume in 1 second (FEV1) – a surrogate marker of lung function decline in COPD – for subjects with increased fruit intake was higher than that for subjects with lower intake of fruits.

Dr Eliana Keranis, Health Center Argalasti Volos, Greece, and colleagues investigated the association between lung function decline and dietary shift to foods rich in antioxidants over a period of three years. Their study is about to be published in the European Respiratory Journal.

They included 120 patients at different severity stages of COPD in their prospective, randomised open-label study. Patients were randomised either to follow a diet based on increased consumption of fresh fruits and vegetables (intervention group: IG), or to follow a free diet (control group: CG). The mean consumption of foods containing antioxidants was higher in the IG than in the CG throughout the study period (p<0.05). Patients were scheduled to attend a medical consultation every 6 months, where spirometry was performed.

After adjusting for confounding factors such as gender/age/smoking-status/comorbidities/exacerbations, the researchers found that the excess antioxidant consumption was associated with a statistically significant improvement in lung function (p<0.01).

Moreover, the study showed that COPD patients who were randomised to follow a diet with a high intake of foods rich in antioxidants (raw fresh fruits and vegetables) exhibited an increase of annual FEV1 while the condition of patients who were on a standard diet worsened, as shown by a decrease in FEV1 over 3 years.

Fruit and vegetables contain significant amounts of antioxidant vitamins such as vitamin C, E and beta-carotene, which may protect the lungs from oxidative damage resulting from smoking and/or air pollution. Those vitamins exert antioxidant and antinflammatory properties, support the normal hydration of airway surfaces and convert oxygen radicals to less-reactive forms, explains Dr Keranis.

Although this hypothesis seems plausible, it cannot be excluded that the beneficial impact of fruit/vegetables on lung function might be due to bioactive nutrients other than antioxidants.

“These findings suggest that a diet rich in antioxidants such as fruit and vegetables may be associated with favourable outcomes in COPD. In this respect, the place of such dietary interventions in the management of COPD warrants consideration,” concludes Dr Keranis.

 

Abstract Number: 577
Title: " Impact of dietary shift to higher antioxidant foods in COPD: A randomized trial."
Author contact: keril_gp@yahoo.gr

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