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Benefits and risks of caffeine and caffeinated beverages

Bryan Bordeaux, DO, MPH
Harris R Lieberman, PhD
Section Editor
Timothy O Lipman, MD
Deputy Editor
Howard Libman, MD


Caffeinated coffee and tea are the most consumed, socially accepted stimulants in the world. Approximately 90 percent of all adults in the world consume caffeine daily. In their natural forms, coffee and tea contain several chemical components that may confer both beneficial and adverse health effects, including caffeine and antioxidants (eg, polyphenols, catechins, and flavonoids).

Most of the data on the health benefits and risks of caffeine are from observational studies in which self-reported consumption of beverages and foods are associated with health outcomes. Such studies make it difficult to identify caffeine itself as the causative agent and to exclude residual confounding. Based on available data, there is insufficient evidence for promoting or discouraging regular coffee and/or tea consumption. Caffeine has multiple systemic effects on the neuropsychiatric, cardiovascular, endocrine, and gastrointestinal systems. The impact on health may be modified by genetic factors, age, sex, medications, and other environmental exposures.

This review will focus on the effects of caffeine and caffeinated beverages on specific disease processes, including insulin resistance, cancer, and all-cause mortality. The specific effects of caffeine on the cardiovascular system, as well as the effects of caffeine on pregnancy, are discussed separately. (See "Cardiovascular effects of caffeine and caffeinated beverages" and "Nutrition in pregnancy".)


Safe levels — For most adults, consumption of up to 400 mg of caffeine a day appears to be safe [1]. A list of commonly consumed caffeinated beverages and average caffeine content is shown in the table (table 1).

Safe levels of caffeine consumption for adolescents have not been established but are presumed to be lower than for adults. Young adults need to be cautioned about using caffeinated energy drinks in excess and not mixing them with other substances. (See 'Dependence and abuse' below.)


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