Selected health and behavioral effects related to the use of caffeine.

This paper reviews the research literature concerning health and selected behavioral effects of caffeine. Epidemiological and laboratory findings are reviewed to determine the health risks associated with both acute and chronic caffeine exposure. Common sources of caffeine, its properties, and physiological effects are considered. The relationships between caffeine and various health conditions are examined including caffeine's association with heart disease, cancer, and benign breast disease. Caffeine's possible contribution to enhanced exercise performance is discussed along with a brief overview of caffeine's effects on mental and emotional health. Over 100 references cited in this review were part of a more extensive literature base obtained from several on-line services including MEDLINE and LEXIS/NEXIS medical data bases. Other sources of relevant literature included manual searches of research journals and the use of selected references from appropriate articles. The relationship between caffeine consumption and various illnesses such as cardiovascular disease and cancer remains equivocal. Prudence might dictate that pregnant women and chronically ill individuals exercise restraint in their use of caffeine, although research suggests relatively low or nonexistent levels of risk associated with moderate caffeine consumption.