Caffeine capers
Caffeine is the most socially accepted stimulant in the world and in the history of the world. Approximately 90 per cent of all adults today consume caffeine in their daily diet. Global consumption of caffeine has been estimated at 120,000 tonnes per year and the trend is increasing, especially among teenagers. This adds extra meaning to the findings of a new study that shows caffeine has definite physical and psychological effects.
Estimations are that since 1977 there has been a 77 per cent increase in the amount of caffeine consumed by teens and even children. This is due largely to the proliferation in energy drinks in the market but also to soft drinks, chocolate and good old tea and coffee. This adds impetus to the need to discover how caffeine affects human function.
We know that caffeine is a central nervous system stimulant. It binds to adenosine receptors in the brain and starts to take effect within an hour with the effects lasting for 3-4 hours. There is great variability though in how caffeine affects people and of course children metabolise it less efficiently. In healthy adults, caffeine\’s half-life (the time taken to remove half of the caffeine in your system) is approximately 4.9 hours. In women taking oral contraceptives, this is increased to 5-10 hours, and in pregnant women the half-life is roughly 9-11 hours. Caffeine can accumulate in individuals with severe liver disease, increasing its half-life up to 96 hours. This is because caffeine is metabolised in the liver.
In the liver caffeine is acted on (metabolised) by cytochrome P450 and transformed into three other substances, which each have their own actions in your body. Paraxanthine (84 per cent) has the effect of increasing fat breakdown, leading to elevated glycerol and free fatty acid levels in the blood. Theobromine (12 per cent) dilates blood vessels and increases urine volume. Theophylline (four per cent) relaxes smooth muscles of the bronchi and is used to treat asthma, although the therapeutic dose of theophylline is much greater than the levels attained from caffeine metabolism.
Given this as a baseline of what caffeine can do, and that many people use it as a booster of mental performance, researchers first of all tested whether it would in fact improve mental function.
To do this, they gave teenagers and children a series of tests designed to test memory, reaction time and colour-word matching. Some of the participants were given caffeine while others were given a placebo. The results showed that caffeine led to an improved performance on memory tests and that females had a greater improvement in reaction time than males. Additionally, females responded differently to caffeine depending on where they were in their menstrual cycle. This suggests that caffeine somehow interacts with sex hormones.
The second was a touch more quirky and equally interesting. In this study, subjects were again given either caffeine or a placebo but this time they were then given a yoghurt that had been flavoured with an unusual flavour. The flavours included almond, maple, peppermint, pumpkin, raspberry-lemon, strawberry-coconut and cumin. When asked to rate the flavour of the yoghurt, the teens and children rated them much more highly if they had been given caffeine with them.
The key thing here, of course, is that caffeine has definite physical and psychological effects and we need to be careful as a society how children are consuming it. The intriguing possibility is that caffeine can increase your preference for new and unusual foods. Could the bold new food frontier for you be trying coffee or tea with your Brussel sprouts?
Estimations are that since 1977 there has been a 77 per cent increase in the amount of caffeine consumed by teens and even children. This is due largely to the proliferation in energy drinks in the market but also to soft drinks, chocolate, and good old tea and coffee. This adds impetus to the need to discover how caffeine affects human function.
We know that caffeine is a central nervous system stimulant. It binds to adenosine receptors in the brain and starts to take effect within an hour with the effects lasting for three to four hours. There is great variability though in how caffeine affects people and of course children metabolise it less efficiently. In healthy adults, caffeine\\\’s half-life (the time taken to remove half of the caffeine in your system) is approximately 4.9 hours. In women taking oral contraceptives, this is increased to 5 to 10 hours, and in pregnant women the half-life is roughly 9 to 11 hours. Caffeine can accumulate in individuals with severe liver disease, increasing its half-life up to 96 hours. This is because caffeine is metabolised in the liver.
In the liver caffeine is acted on (metabolised) by cytochrome P450 into three other substances which each have their own actions in your body. Paraxanthine (84 per cent) has the effect of increasing fat breakdown leading to elevated glycerol and free fatty acid levels in the blood. Theobromine (12 per cent) dilates blood vessels and increases urine volume. Theophylline (four per cent) relaxes smooth muscles of the bronchi, and is used to treat asthma although the therapeutic dose of theophylline is much greater than the levels attained from caffeine metabolism.
Given this as a baseline of what caffeine can do, and that many people use it as a booster of mental performance, researchers first of all tested whether it would in fact improve mental function.
To do this they gave teenagers and children a series of tests designed to test memory, reaction time, and colour-word matching. Some of the participants were given caffeine while others were given a placebo. The results showed that caffeine led to an improved performance on memory tests and that females had a greater improvement in reaction time than males. Additionally, females responded differently to caffeine depending on where they were in their menstrual cycle. This suggests that caffeine somehow interacts with sex hormones.
The second was a touch more quirky and equally interesting. In this study subjects were again given either caffeine or a placebo but this time they were then given a yoghurt that had been flavoured with an unusual flavour. The flavours included almond, maple, peppermint, pumpkin, raspberry-lemon, strawberry-coconut, and cumin. When asked to rate the flavour of the yoghurt the teens and children rated them much more highly if they had been given caffeine with them.
The key thing here of course, is that caffeine has definite physical and psychological effects and we need to be careful as a society how children are consuming it. The intriguing possibility is that caffeine can increase your preference for new and unusual foods. Could the bold new food frontier for you be trying coffee or tea with your brussel sprouts?
