Long-term studies have shown that coffee consumption might protect against DNA damage in humans. Coffee has also been associated with a reduced risk of conditions such as diabetes, Parkinson’s disease, and some cancers. The responsible components might be chlorogenic acids and Maillard reaction products generated during roasting. These compounds could act as radical scavengers. If that is the case, the protective effect should alreadly be observable shortly after coffee consumption.

Elke Richling, University of Kaiserslautern, Germany, and colleagues performed a short-term study of the effects of coffee consumption on DNA breaks. 13 healthy subjects drank four 200 mL cups of coffee over a period of eight hours and blood samples were taken at regular intervals. The samples’ DNA integrity was tested using the so-called comet assay, a simple technique involving single-cell gel electrophoresis. The results showed a significant reduction of DNA strand breaks as soon as two hours after the first cup of coffee, and the protective effect increased during the test period. The researchers observed a damage reduction of up to 30 % compared the baseline before coffee intake.

These results indicate that coffee has a direct and immediate effect, most probably caused by compounds with rapid uptake and radical scavenging properties such as chlorogenic acids and their metabolites.

• Coffee consumption rapidly reduces background DNA strand breaks in healthy humans: Results of a short term repeated uptake intervention study,
  Tamara Bakuradze, Roman Lang, Thomas Hofmann, Dorothea Schipp, Jens Galan, Gerhard Eisenbrand, Elke Richling,
  Mol. Nutr. Food Res. 2015.
  DOI: 10.1002/mnfr.201500668