Side effects of high intake of caffeine
The EFSA opinion advises that for most individuals, caffeine intakes of up 400mg per day are unlikely to cause adverse effects. However, individuals who are sensitive to caffeine at low doses and/or individuals with underlying health conditions may experience some side effects such as jitteriness, anxiety or difficulty concentrating.
Short term adverse effects of an excessive consumption of caffeine in children and adults include interrupted sleep, anxiety and behavioural changes. Longer term consumption of excess caffeine has been linked to cardiovascular issues i.e. effects on the heart and blood vessels.
High exposure of caffeine is associated with increased tension, nervousness, anxiety, irritability, nausea, pins and needles sensation, tremor, - sweating, palpitations (racing irregular heartbeat), restlessness and possibly dizziness. These effects may be more severe in individuals who are caffeine sensitive and/or have underlying health issues such as heart disease or high blood pressure, and effects may occur at lower doses.
Excessive caffeine consumption is associated with a number of serious adverse effects such rapid heart rate, abnormal heart rhythms and seizures, which have been observed at intakes of approximately 1.2 grams (1,200 mg) of caffeine. Excessive consumption of caffeine during pregnancy has been associated with an increased risk of stunted foetus development.
Caffeine intakes of above 10-14 grams (10,000 mg – 14,000 mg) have been reported to be fatal, although smaller doses can also be life-threatening to sensitive populations. These cases have occurred where pure caffeine has been measured incorrectly.