"The analysis that we did showed the amount of caffeine ranged from 50mg per cup from Starbucks, up to over 300mg per cup from another coffee house, Patisserie Francoise," he said.
For doses lower than 10 mg/kg, the half-life of caffeine ranges from two and a half hours to four and a half hours, with no significant difference between young and elderly humans [ 2].
In blood, linearity was observed for caffeine concentrations ranging from 10 to 500 mg/l with a correlation coefficient of 0.999.
There was, however, a high variability in baseline caffeine levels ranging from sub-detection levels to 1942 ng/ml.
The European Food Safety Authority (EFSA) said single doses of up to 200mg of caffeine from a range of sources – such as tea, coffee, chocolate and energy drinks – should be a safe level for most healthy adults.
Snuff products or herbal powders, claiming to contain caffeine and a range of other plant-based ingredients, are also being sold as a legal alternatives to cocaine and amphetamines.
When combined with analgesics, caffeine produces a range of clinical effects in these patients.
Energy drinks can also contain caffeine in the range of 75 to 200 mg caffeine or more per serving.
Typically, administration of caffeine in the range of 50 to 150 mg improves reaction times, psychomotor function, attention, vigilance and alertness-with the effects being particularly evident in fatigued individuals.
Numerous dietary supplements also contain caffeine with doses ranging from 30 to 200 mg, sometimes even higher, leading to a concentration up to 10 mg/l.
