A diet rich in whole grains and nuts but low on red meat and sugary drinks is associated with a reduced risk of developing chronic lung disease, according to the BMJ study.
The study analysed data from over 120,000 US patients who took part in biennial health questionnaires throughout the late '80s and '90s. Patients who reported having asthma or COPD at baseline were excluded.
Although the predominant risk factor for COPD in the developed world is smoking, up to a third of patients have never smoked, suggesting other risk factors could play a role.
Researchers from France and Harvard University in the US calculated the Alternative Healthy Eating Index (AHEI-2010) scores, a measure of diet quality, for these patients.
The AHEI-2010 is calculated based on 11 components. A higher score indicates a high intake of vegetables, whole grains, polyunsaturated fats, nuts and long chain omega-3 fats, and lower intake of alcohol, red and processed meats, refined grains and sugar-sweetened drinks.
Poor diet a risk factor
Over the study period, almost 900 patients were diagnosed with COPD. The researchers then investigated whether the likelihood of developing COPD was linked to diet quality.
They found that patients with the lowest AHEI-2010 values – and hence poorer diets – were a third more likely to be diagnosed with COPD than those who had the best quality diets, suggesting that poor diet could be a risk factor for poor lung health.
The results were consistent across genders and independent of smoking status.
The study authors said: ‘This is a novel finding that supports the importance of diet in the pathogenesis of COPD. Although efforts to prevent COPD should continue to focus on smoking cessation, these prospective findings support the importance of a healthy diet in multi-interventional programmes to prevent COPD.
‘Our results encourage clinicians to consider the potential role of the combined effect of foods in a healthy diet in promoting lung health.’
The researchers found no association between AHEI-2010 diet score and adult-onset asthma.
COPD is thought to be the third leading cause of death worldwide.
