Chronic obstructive pulmonary disease and intake of catechins, flavonols, and flavones: the MORGEN Study

Flavonoids have been suggested to protect against chronic lung disease. We studied intake of catechins, flavonols, and flavones in relation to pulmonary function and COPD symptoms in 13,651 adults from three Dutch cities examined from 1994 to 1997. Dietary intake was estimated using a food frequency questionnaire, and flavonoid intake was calculated using specific food composition tables. Pulmonary function (FEV1) was determined by spirometry and COPD symptoms by questionnaire. Associations were presented for the fifth versus the first quintile of intake (Q5-Q1), adjusted for age, height (for FEV1 only), sex, smoking, BMI, and energy intake. Smoking was strongly associated with COPD, independent of dietary effects. Average catechin, flavonol, and flavone intake was 58 mg/d (SD = 46) with tea and apples as main sources. Total catechin, flavonol, and flavone intake was positively associated with FEV1 (beta(Q5-Q1) = 44 ml, 95% CI = 18-69) and inversely associated with chronic cough (OR(Q5-Q1) = 0.80, 95% CI = 0.66-0.97) and breathlessness (OR(Q5-Q1) = 0.74, 95% CI = 0.58- 0.94), but not chronic phlegm. Catechin intake was independently associated with FEV1 (beta(Q5-Q1) = 130 ml, 95% CI = 101-159) and all three COPD symptoms (OR(Q5-Q1) = 0.60-0.72, p < 0.001). Flavonol and flavone intake was independently associated with chronic cough only. Solid fruit, but not tea, intake was beneficially associated with COPD. Our results suggest a beneficial effect of a high intake of catechins and solid fruits against COPD.