Diet quality tied to slower lung decline in COPD

Clinical takeaway: Diet quality may be worth raising with COPD patients as a low-cost adjunct to standard therapy. 

Patients with COPD often ask what they can do beyond inhalers. Smoking cessation and pulmonary rehabilitation carry strong evidence, but advice about food has mostly been borrowed from cardiovascular prevention rather than grounded in respiratory outcomes. That leaves clinicians with little to say when a motivated patient wants to know whether eating better will help their lungs. 

Healthier dietary patterns, rich in fruits, vegetables, and whole grains, have been associated with better lung function, but mostly in general-population samples, often small ones, and usually with disease risk rather than lung function as the outcome. Whether people who already have airway disease stand to gain more or less from a better diet remained an open question. It's also a plausible one, since both asthma and COPD run at higher baseline inflammation and oxidative stress levels that an anti-inflammatory eating pattern might impact. A large Dutch population-based cohort analysis now takes that question on directly, comparing the diet and lung function relationship in people with and without airway disease over roughly a decade. 

The clearest signal came from people with COPD. Higher diet quality was associated with better lung function at baseline, and the association was significantly stronger in participants with COPD than in those without airway disease, a pattern that held at every level of disease severity and grew larger as severity worsened. Across the full cohort, each one-point increase on the 48-point diet score was associated with about 5 mL higher FEV1. In people with COPD, each point was associated with an additional 8.31 mL gain on top of that, the difference that marks the stronger relationship. For scale, the cohort overall lost about 23 mL of FEV1 per year, and the threshold usually treated as clinically meaningful in COPD is around 100 mL. 

Across roughly 10 years of follow-up, lung function declined more slowly in people with COPD who ate better at baseline, with significantly slower loss of FEV1, FVC, and their ratio compared with participants without COPD. The slower decline concentrated in mild and moderate disease; the most severe group was too small to assess. 

Participants with asthma showed a stronger cross-sectional association between diet and FEV1 than those without airway disease, but no significant association with slower decline emerged over follow-up. The authors suggest that factors such as medication use and disease management may outweigh diet in shaping lung function change over time in asthma. 

The findings come from Lifelines, a prospective population-based Dutch cohort. Researchers analyzed 83,460 adults with baseline spirometry and dietary data, 37,752 of whom had follow-up spirometry over roughly a decade. Diet was scored once, at baseline, from a food frequency questionnaire graded against Dutch dietary guidelines, rewarding vegetables, fruit, whole grains, legumes, nuts, and fish while penalizing red and processed meat, butter, hard margarines, and sugar-sweetened drinks. COPD was defined spirometrically, as a pre-bronchodilator FEV1/FVC below 70 percent, rather than by physician diagnosis; asthma was self-reported physician diagnosis. 

Without intervention trials, the results cannot become formal dietary prescriptions for COPD, and no diet is likely to match the effect of pharmacotherapy. But the pattern they describe, a stronger diet signal exactly where inflammation and oxidative stress run highest, gives the association biological footing and gives clinicians a defensible reason to treat food as part of COPD care rather than an afterthought. 

"Higher diet quality was associated with better lung function and slower lung function decline in individuals with COPD and across COPD severity stages," the authors conclude. "Among individuals with asthma, significant associations were observed only in cross-sectional analyses. These findings support the potential role of diet as a modifiable lifestyle factor in respiratory health, especially in participants with COPD." 

Source: Martinez-Rodriguez AF, et al. (2026 Mar 19) ERJ Open Res. Healthy diet is associated with better lung function, especially in individuals with COPD: findings from the Lifelines cohort study