half a liter per day of coffee is a lot! I wonder if they controlled for caffeine
some highlights from my reading:
- 372mg caffeine per day
- water-only group specifically avoided caffeine
- coffee/caffeine group had to abstain from all caffeine for 4 weeks before study (baseline to 300+mg a day is a LOT for someone with no tolerance)
- they base their claim of the 'darkness' of the roast mattering on other similar studies, with less pronounced results, that used lighter roasts.
"Among several previous studies of the effects of coffee consumption on DNA damage, only two were randomised controlled trials, with DNA breakage rather than oxidative modification of DNA bases analysed [23]. Bakuradze et al. [14] also studied the effects of coffee C21 consumption, after 4 weeks of intervention, and found a decrease of DNA strand breaks by 27% in comparison to the control group with water consumption (p<0.001). Misik et al. [22] studied a much shorter intervention period (5 days) and a different coffee type and used isolated lymphocytes. In comparison to C21, the coffee had an approximately twofold content of caffeoyl quinic acids and trigonelline and about half of N-methylpyridinium. Therefore, the coffee used by Misik et al. is a light/ medium roast type while we used here a dark roast blend. We assume that the different degree of roasting accounts for the different outcome observed. "