From the Guidelines
For most healthy adults, a safe daily caffeine intake is up to 400 milligrams, as recommended by the DGA 1. This is roughly equivalent to 4 cups of brewed coffee, 10 cans of cola, or 2 energy shot drinks. However, individual tolerance varies based on factors like body weight, medications, and health conditions.
Key Considerations:
- Pregnant women should limit intake to 200 milligrams daily, as advised by the European Food Safety Authority 1.
- Adolescents should consume no more than 100 milligrams, which is equivalent to 2.5 mg · kg body weight –1 · d–1 1.
- Children should generally avoid caffeine due to the potential risk of behavioral issues and anxiety 1.
- People with certain health conditions like anxiety disorders, high blood pressure, heart problems, or sleep disorders may need to further restrict their caffeine consumption.
Mechanism and Side Effects:
Caffeine works by blocking adenosine receptors in the brain, which helps you feel more alert but can cause side effects like jitteriness, increased heart rate, and insomnia when consumed in excess. If you're sensitive to caffeine or taking medications, it's best to start with lower amounts and monitor how your body responds. Consuming caffeine earlier in the day rather than in the evening can help prevent sleep disruption. It's essential to consider the overall diet and account for nutrients and calories from dairy, added sugars, and additions when consuming coffee and tea 1.
From the Research
Safe Caffeine Intake
- The safe caffeine intake for healthy adults is up to 400 mg per day, as supported by a systematic review of potential adverse effects of caffeine consumption 2.
- For healthy pregnant women, the safe caffeine intake is up to 300 mg per day, as evidence suggests that consumption of up to this amount is generally not associated with adverse reproductive and developmental effects 2.
- For children and adolescents, the available evidence suggests that 2.5 mg caffeine/kg body weight/day remains an appropriate recommendation 2.
- However, other studies suggest that caffeine intake may be associated with an elevated risk of anxiety, especially when the intake dose is greater than 400 mg 3.
- Additionally, maternal caffeine consumption has been linked to negative pregnancy outcomes, including miscarriage, stillbirth, low birth weight, and childhood acute leukemia, with no threshold of consumption below which associations were absent 4.