From the Guidelines
The maximum recommended caffeine intake for healthy adults is 400 milligrams per day. This is based on the most recent guidelines from the Dietary Guidelines for Americans (DGA) as reported in the study by 1. According to this study, limiting caffeine intake to <400 mg/d is recommended.
Key Considerations
- Pregnant women should limit their intake to 200 milligrams daily, as advised in the study by 2.
- Adolescents should consume no more than 2.5 mg · kg body weight –1 · d–1, which is approximately 100 milligrams per day for a 40 kg adolescent, as noted in the study by 2.
- Children should generally avoid caffeine due to their smaller body size and potential sensitivity to its effects.
- Exceeding these limits can lead to negative side effects such as insomnia, jitters, increased heart rate, headaches, anxiety, and digestive issues, as individual tolerance varies based on body weight, medications, and overall health status.
- Those with certain medical conditions like heart problems, high blood pressure, or anxiety disorders should consider further limiting caffeine intake or consulting with a healthcare provider.
- It's also important to be aware that caffeine is found in many products beyond coffee, including tea, chocolate, energy drinks, some medications, and certain supplements, so tracking total daily consumption from all sources is necessary to stay within safe limits, as highlighted in the study by 1.
Additional Recommendations
- When consuming coffee and tea, account for nutrients and calories from dairy, added sugars, and additions within the overall diet, as recommended in the study by 2.
- Decaffeinated coffee and tea can also serve as healthy beverage choices because the phenolic acids and flavonoids associated with health benefits, although modestly reduced in amounts, are present in these products, as noted in the study by 2.
From the Research
Caffeine Intake Guidelines
The amount of caffeine that can be safely consumed per day is a topic of ongoing research. According to the available evidence:
- Moderate intake of caffeine is generally considered safe and may have health benefits, such as protecting against cardiovascular diseases, obesity, and diabetes mellitus 3.
- The long-term or excessive consumption of caffeine can lead to addiction, insomnia, migraine, and other side effects 3.
- Children, adolescents, pregnant women, and people who are sensitive to caffeine should restrict or reduce their intake to avoid potential adverse effects 3.
Daily Caffeine Limit
- One study suggests that cardiovascular effects experienced by caffeine consumers at levels up to 600 mg/day are in most cases mild, transient, and reversible, with no lasting adverse effect 4.
- However, the evidence considered within this review suggests that typical moderate caffeine intake is not associated with increased risks of total cardiovascular disease; arrhythmia; heart failure; blood pressure changes among regular coffee drinkers; or hypertension in baseline populations 4.
- Another study found that the administration of 200-300 mg caffeine produced a mean increase of 8.1 mm Hg in systolic BP and of 5.7 mm Hg in diastolic BP, but no increase in BP was observed after coffee was compared with a caffeine-free diet or was compared with decaffeinated coffee 5.
Individual Variability
- The cumulative effect of coffee and a mental stress task on heart rate, blood pressure, and mental alertness is similar in caffeine-naïve and caffeine-habituated females, suggesting that individual variability plays a role in caffeine sensitivity 6.
- The dose of caffeine used in studies can vary, and the changes in cardiovascular and mental alertness responses have been mostly determined in male caffeine-habituated consumers, highlighting the need for more research on individual differences 6.