Coffee consumption seems generally safe within usual levels of intake.
Coffee is one of the most commonly consumed beverages worldwide. As such, even small individual health effects could be important on a population scale. There have been mixed conclusions as to whether coffee consumption is beneficial or harmful to health, and this varies between outcomes. Roasted coffee is a complex mixture of over 1000 bioactive compounds, some with potentially therapeutic antioxidant, anti-inflammatory, antifibrotic, or anticancer effects that provide biological plausibility for recent epidemiological associations. Key active compounds include caffeine, chlorogenic acids, and the diterpenes, cafestol and kahweol. The biochemistry of coffee has been documented extensively elsewhere.4 Coffee undergoes a chemical metamorphosis from the unroasted green bean, and the type of bean (Arabica versus Robusta), degree of roasting, and preparation method including coffee grind setting and brew type, will all have an influence on the biochemical composition of the final cup. An individual’s genotype and gut microbiome will then determine the bioavailability and type of coffee metabolites to which that individual is exposed.
Coffee consumption seems generally safe within usual levels of intake, with summary estimates indicating largest risk reduction for various health outcomes at three to four cups a day, and more likely to benefit health than harm. Robust randomised controlled trials are needed to understand whether the observed associations are causal. Importantly, outside of pregnancy, existing evidence suggests that coffee could be tested as an intervention without significant risk of causing harm. Women at increased risk of fracture should possibly be excluded.