Some people cannot start the day without a large mug of coffee or a warm cup of tea to perk them up. However, they might not need the kick-start as much as they think they do, as caffeine is likely to already be in their blood.
Whether brewed in your kitchen or bought from a coffee packaging machine, for many people, the brown stuff is addictive because it provides a caffeine boost that gives you more energy and makes you alert.
Most people are so enamoured with coffee and tea that a study from Oregon State University found every one of 18 batches of human blood tested positive for caffeine.
The research, published in the Journal of Pharmaceutical and Biomedical Analysis, revealed blood is not necessarily pure, as it can be contaminated with caffeine, as well as other drugs, such as anti-anxiety medication alprazolam; tolbutamide, used for type 2 diabetics; and dextromethorphan, a cough suppressant.
PHD student Luying Chen, who worked on the study, said: “From a ‘contamination’ standpoint, caffeine is not a big worry for patients, though it may be a commentary on current society.”
It is not just tea and coffee that could spike results though, as chocolate, energy drinks and some soft drinks also contain caffeine.
While many of us perhaps do not want our tea-drinking habits to be revealed in a blood test, a recent study by the National University of Singapore, the University of Essex and the University of Cambridge reported that drinking the beverage could be good for brain function.
Those who drink green, black or oolong tea four times a week or more for 25 years had good connections between their brain regions, improving their cognitive abilities.