Dietary catechins and epithelial cancer incidence: the Zutphen elderly study

The flavonoids, a group of more than 4,000 polyphenolic antioxidants, are potential cancer preventive components of fruits and vegetables. Catechins, one of the 6 major groups of flavonoids, are present in high concentrations in tea as well. Our objective was to evaluate the association between intake of catechins and incidence of epithelial cancers with data from the Zutphen Elderly Study, a prospective cohort study among 728 men aged 65-84 years in 1985. The average catechin intake at baseline was 72 mg/day (range, 0-355 mg/day). After 10 years of follow-up, 96 incident epithelial cancers were recorded, including 42 cases of lung cancer. After multivariate adjustment, catechin intake was not associated with epithelial cancer (risk ratio [RR] from lowest to highest tertile: 1.00, 0.75, 0.94; p for trend: 0.82), or lung cancer (RR from lowest to highest tertile: 1.00, 0.72, 0.92; p for trend: 0.80). Catechins not from tea were borderline significantly inversely associated with lung cancer incidence (RR and 95% confidence interval [CI] for a 7.5-mg increase in intake: 0.66, 0.42-1.05), whereas catechins from tea were not. Catechins from apple, the major source of non-tea catechins, were also related to lung cancer incidence (RR and 95% CI for a 7.5-mg catechin increase: 0.67, 0.38-1.17). Because tea, the major catechin source in this population, was not associated with cancer risk, it seems unlikely that catechins are responsible for the observed inverse trend between non-tea catechins and lung cancer incidence. However, differences in bioavailability of the various catechins may play a role; effects on individual cancer sites cannot be excluded and merit further investigation.