Methods and results

In a short‐term human intervention study, we determined the effects of coffee intake on DNA integrity during 8 h. Healthy male subjects ingested coffee in 200 mL aliquots every second hour up to a total volume of 800 mL. Blood samples were taken at baseline, immediately before the first coffee intake and subsequently every 2 h, prior to the respective coffee intake. DNA integrity was assayed by the comet assay. The results show a significant (p < 0.05) reduction of background DNA strand breaks already 2 h after the first coffee intake. Continued coffee intake was associated with further decrements in background DNA damage within the 8 h intervention (p < 0.01 and p < 0.001, respectively). Mean tail intensities (TIs%) decreased from 0.33 TI% (baseline, 0 h) to 0.22 TI% (within 8 h coffee consumption).