From the Guidelines
The maximum recommended caffeine intake for most healthy adults is 400 milligrams per day, as stated by the Dietary Guidelines for Americans (DGA) 1, 2, 3.
Key Considerations
- This is roughly equivalent to four 8-ounce cups of brewed coffee, 10 cans of cola, or two energy shot drinks.
- Pregnant women should limit their intake to 200 milligrams daily, as advised by the European Food Safety Authority 1.
- Adolescents should consume no more than 100 milligrams per day, and children should generally avoid caffeine altogether, with a recommended limit of 2.5 mg · kg body weight –1 · d–1 1, 3.
Potential Risks
- Exceeding these limits can lead to negative side effects including insomnia, jitters, increased heart rate, headaches, anxiety, and digestive issues.
- 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.
Additional Factors
- It's also important to be aware of hidden sources of caffeine in medications, chocolate, and some foods.
- Caffeine works by blocking adenosine receptors in the brain, preventing drowsiness and temporarily boosting alertness, but consuming too much can overstimulate your nervous system and cause unpleasant symptoms.
Recommendations
- The DGA recommends limiting caffeine intake to 400 mg/d, and pregnant women are advised to consume no more than 200 mg caffeine/d 2, 3.
- Decaffeinated coffee and tea can also serve as healthy beverage choices because the phenolic acids and flavonoids associated with health benefits are present in these products, although modestly reduced in amounts 3.
From the Research
Maximum Caffeine Intake
- The maximum recommended caffeine intake varies depending on the population, with healthy adults generally considered to be safe up to 400 mg/day 4, 5.
- For children and adolescents, the recommended maximum intake is 2.5-3 mg/kg body weight per day 4, 5.
- Pregnant and lactating women, as well as people with underlying heart or other health conditions, should be cautious with their caffeine intake and consider reducing it to avoid potential adverse effects 4, 6.
- The European Food Safety Authority and Health Canada have established similar guidelines for caffeine intake, with a maximum recommended intake of 400 mg/day for adults and 2.5-3 mg/kg body weight per day for children and adolescents 5.
Factors Affecting Caffeine Intake
- Coffee, tea, and soft drinks are the most important sources of caffeine in the diet 5.
- Energy drinks contribute relatively little to total caffeine intake across all age groups 5.
- Individual sensitivity to caffeine can vary greatly, with some people experiencing adverse effects at much lower doses than others 7, 8.
- The timing and dose of caffeine consumption can also impact its effects, with higher doses and consumption later in the day potentially disrupting sleep and reducing attention accuracy 7, 8.
Health Effects of Caffeine
- Moderate caffeine intake has been associated with several health benefits, including antioxidant and anti-inflammatory activities, and protective effects on cardiovascular diseases, obesity, and neurodegenerative diseases 6.
- Excessive caffeine consumption, on the other hand, can lead to addiction, insomnia, migraine, and other side effects 6, 7.
- Caffeine can also have negative effects on sleep quality, particularly in older adults and individuals with certain genetic polymorphisms 7.