Vol.:(0123456789) 1 3 European Journal of Nutrition https://doi.org/10.1007/s00394-018-1863-2 ORIGINAL CONTRIBUTION Consumption of a dark roast coﬀee blend reduces DNA damage in humans: results from a 4-week randomised controlled study Dorothea Schipp 4 · Jana Tulinska 1 · Maria Sustrova 1 · Aurelia Liskova 1 · Viera Spustova 1 · Miroslava Lehotska Mikusova 1 · Zora Krivosikova 1 · Katarina Rausova 2 · Andrew Collins 3 · Vaineta Vebraite 3 · Katarina Volkovova 3 · Eva Rollerova 2 · Magdalena Barancokova 1 · Sergey Shaposhnikov 3 Received: 15 July 2018 / Accepted: 14 November 2018 © Springer-Verlag GmbH Germany, part of Springer Nature 2018 Abstract Purpose To determine the DNA protective eﬀects of a standard coﬀee beverage in comparison to water consumption. Methods The single-blind, randomised controlled study with parallel design included healthy women (n = 50) and men (n = 50) recruited from the general Central European population. The subjects were randomised in a coﬀee and a control group, with stratiﬁcation for sex and body mass index. The study comprised two periods of 4 weeks: a preconditioning period, with daily consumption of at least 500 ml water but no coﬀee, nor tea, nor any other caﬀeine-containing product. During the subsequent intervention period the coﬀee group consumed 500 ml of freshly brewed dark roast coﬀee blend per day, the control group consumed water instead. On the last day of each period, blood was drawn and analysed by comet assay (single-cell gel electrophoresis) to assess the level of DNA damage (strand breakage). Results At the end of the intervention period the mean level of DNA strand breaks in the coﬀee group has decreased in comparison to the control group [diﬀerence in means 0.23% TI (tail intensity), p = 0.028]. The mean change from baseline (delta value) was − 23% in the coﬀee group (p = 0.0012). Eﬀects of coﬀee intake were similar for men and women. During intervention, neither group showed any signiﬁcant change in body weight or calorie intake. Conclusions Our results indicate that regular consumption of a dark roast coﬀee blend has a beneﬁcial protective eﬀect on human DNA integrity in both, men and women. Keywords Coﬀee · Comet assay · Human intervention study · DNA strand breaks · DNA damage Abbreviations BMI Body mass index CQA Caﬀeoylquinic acid ITT Intention to treat NMP N-Methylpyridinium PP Per protocol SD Standard deviation TI Tail intensity WRST Wilcoxon rank sum test WSRT Wilcoxon signed rank test Introduction It is known that a range of disorders are associated with an impairment of cell DNA integrity due to increased damage to DNA. Among these disorders, there are certain cancers, cardiovascular diseases, diabetes and inﬂammatory bowel diseases. Numerous epidemiological and experimental data suggest that coﬀee consumption is associated with a reduced risk of developing these diseases [1–6]. Previ- ous investigations have shown DNA-protective eﬀects of coﬀee constituents with diﬀerent chemical compositions [7–10]. It was assumed that a probable mechanism respon- sible for protection of DNA is the induction of a resistant state towards toxic compounds by pre-incubation with cof- fee constituents. For instance, several coﬀee constituents * Dorothea Schipp kontakt@ds-statistik.de 1 Medical Faculty, Slovak Medical University, Bratislava, Slovakia 2 Faculty of Public Health, Slovak Medical University, Bratislava, Slovakia 3 Norgenotech AS, Skreia, Norway 4 Statistical Consulting, Pirnaer Str. 1, 01824 Rosenthal-Bielatal, Germany