Caffeinated drinks are commonly consumed throughout the World with tea and coffee providing a significant contribution. A recent study conducted on a United States population measured the concentrations of caffeine and some of its metabolites in the urine of subjects1. The median concentration of caffeine and its metabolites detected was 1 μmol/L with 9 analytes (caffeine, theophylline, paraxanthine, 1-methylxanthine, 1-methyluric acid, 1,3-dimethyluric acid, 1,7-dimethyluric acid, 1,3,7-trimethyluric acid, and 5-acetylamino-6-amino-3-methyluracil) showing moderate correlations with caffeine intake as would be expected. Higher caffeine and caffeine metabolite excretion was detected in the urine of men compared to women and this was reflected in higher caffeine intakes in men. Caffeine intake appears therefore to be widespread amongst the Unites States population and the use of a number of metabolites appears to be a reasonable way of estimating the caffeine intake of a population.
These results in themselves may not the overly interesting, but do confirm that caffeine is a widely consumed drink within the United States. Estimates of consumption amounts suggest that about 200 mg caffeine is consumed each day on average. Evidence suggest that caffeine in moderation poses no real negative health effects, and the only real evidence for a detrimental effect comes from weak associations with certain diseases in epidemiological studies, and in studies using very high concentrations. Caffeine for example can induce irregular heart beats in sensitive individual and at very high intakes in some habitual caffeine drinkers. Caffeine has also shown some beneficial associations such as a reduction in Parkinson’s disease. However, the exact relationship is not fully understood, and confounding variables may play a part (such as the antioxidants in tea and coffee that can protect neurones). Therefore regular moderate caffeine intake does not seem to pose any health problem and may have potential benefits.
RdB
