Caffeine is the most widely consumed psychoactive drug in the world. Natural sources of caffeine include coffee, tea, and chocolate. Synthetic caffeine is also added to products to promote arousal, alertness, energy, and elevated mood. Over the past decade, the introduction of new caffeine-containing food products, as well as changes in consumption patterns of the more traditional sources of caffeine, has increased scrutiny by health authorities and regulatory bodies about the overall consumption of caffeine and its potential cumulative effects on behavior and physiology. Of particular concern is the rate of caffeine intake among populations potentially vulnerable to the negative effects of caffeine consumption: pregnant and lactating women, children and adolescents, young adults, and people with underlying heart or other health conditions, such as mental illness. Here, we review the research into the safety and safe doses of ingested caffeine in healthy and in vulnerable populations. We report that, for healthy adults, caffeine consumption is relatively safe, but that for some vulnerable populations, caffeine consumption could be harmful, including impairments in cardiovascular function, sleep, and substance use. We also identified several gaps in the literature on which we based recommendations for the future of caffeine research.

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The Safety of Ingested Caffeine: A Comprehensive Review.

Coffee, caffeine, and sleep: A systematic review of epidemiological studies and randomized controlled trials.

Systematic review of the potential adverse effects of caffeine consumption in healthy adults, pregnant women, adolescents, and children

Coffee, Caffeine, and Health In many countries, a large majority of adults consume caffeine daily. This review summarizes the evidence about the varied physiological effects of caffeine and coffee ...

https://www.nejm.org/doi/pdf/10.1056/NEJMra1816604

Coffee, Caffeine, and Health

Trends in intake and sources of caffeine in the diets of US adults: 2001–2010

https://cyberleninka.org/article/n/246687.pdf

Robyn Teplansky

Papers

Beverage caffeine intakes in the U.S.

Assessing dietary exposure to caffeine from beverages in the U.S. population using brand-specific versus category-specific caffeine values

Caffeine Intakes from Beverages in the U.S.