In Reply We thank Dr Palatini for the attention given to our study of coffee consumption and incident tachyarrhythmias.1 Dr Palatini discusses the importance of variations among types of coffee and the overall health effects of these substances.
When we defined a serving of coffee for our study, we attempted to be as inclusive as possible given the available data in the UK Biobank; however, we were unable to conduct subgroup analyses to disentangle associations with each type of coffee drink “on the menu” (so to speak). Therefore, it is possible that different types of coffee drinks may be associated with different arrhythmia risks, whether related to the specific components of a drink, the levels of caffeine, or the timing of the resultant caffeine load. However, we did not identify any meaningful interactions among caffeine metabolism-related genetic variants, the amount of coffee consumed, and the relative influence on arrhythmia risk.1 Our findings suggest that neither the amount nor the rapidity of caffeine exposure had detectible adverse consequences on arrhythmia risk. A common fallacy in nutrition research is the biological plausibility of effects inferred from the individual components of a consumed substance. These analyses should be viewed as hypothesis-generating work; conclusions about the actual health effects should be reserved for analyses of the whole food or substance itself. Whole food analyses are best achieved through interventional experiments rather than observational studies—a limitation of our study.