Caffeine is a naturally occurring chemical called an alkaloid. It is found in the seeds, leaves and fruits of over 60 different types of plants, chiefly coffee and tea, but also in chocolate and some herbal beverages.
Caffeine is a mild central nervous system stimulant that has a number of effects on the body. In addition to the appeal of the aroma and taste, these effects are without a doubt a reason for the popularity of caffeine containing beverages. According to current Government of Canada statistics, Canadians get about 60 per cent of their caffeine on average from coffee and 30 per cent from tea. The balance comes from caffeinated soft drinks and medications.
Sensitivity to caffeine is highly variable. While some can enjoy several cups of coffee in an hour with little or no effect, others will notice the effect of a single cup.
There is a natural tendency to self-select the amount of caffeine you wish to consume on a regular basis. However, like many of the good things in life, moderation is the key to enjoying the positive aspects of coffee and caffeine without incurring any effects that may be linked to over consumption.
Caffeine stimulates the central nervous system in a manner that causes a short term elevation of blood pressure, an increased metabolic rate and increased blood flow to the muscles.
What this produces in terms of the sensation and experience of consuming caffeine for most people is a variety of physical and psychological effects. These include enhanced mental alertness, an increased ability to concentrate, swift reaction times and prolonged vigilance for performing tasks
(brain activity section).
Coffee also seems to be a mood elevator for most people and even has been linked to a reduced risk for depression amongst regular coffee drinkers. Coffee also impacts physical as well as mental endurance, which is why it can be used to enhance athletic performance (link to coffee and exercise section).
Moderate caffeine consumption has almost always been found to be free from adverse effects and research conducted over the last ten to twenty years has in fact established some beneficial effects.
The effects of caffeine in coffee vary greatly between individuals. Those who are most sensitive should probably stop caffeine consumption at least several hours prior to going to bed. Others may enjoy coffee even late into the evening with no sleep disruption. The effects on sleep patterns (link to section on brain activity) are likely very subjective and may be influenced by how regular the use, the amount of coffee consumed and the level of enjoyment or sensitivity.
Certainly, one can take in too much caffeine and for some this will result in feeling jittery. Forgoing consumption for four to five hours should remove this feeling. It is advisable to review how much caffeine is actually consumed from all sources and note that level to moderate future intake patterns.
Dangerous levels of caffeine can produce more serious side effects. These cases almost always involve over the counter medications rather than beverages and typically involve dosages of caffeine that would be equal to a minimum of one hundred or more cups of regular coffee.
For those who want to enjoy coffee with less stimulation, decaffeinated coffee is an option.
As previously mentioned, caffeine tolerances and preferences will vary greatly amongst individuals but there some rough guidelines available to help evaluate consumption. In recent years, Health Canada conducted a very thorough review of past and current caffeine research and set standards which allow for reasonable limits for caffeine intake.
These limits are:
For average adults a guideline limit of 400-450 milligrams of caffeine per day.
For women planning to become pregnant, pregnant or nursing newborns they advise a moderated level of no more than 300 milligrams per day.
For preteens they have recommended daily limits tied to the body weight of the child.
Below is a table summarizing widely found levels of caffeine in popular products. The reason for the range of caffeine levels amongst coffee and tea products is due to the variability of caffeine within natural products as compared to the controlled amounts put into man-made beverages.
Almost all relevant authorities believe that caffeine is not a genuinely addictive product. There are several criteria given as to why caffeine is not considered an addictive substance compared to other beverages, such as alcohol, and many recreational drug substances that are considered to be addictive.
With coffee consumption, there is little or no increased tolerance to dose, so a coffee lover does not need to increase amounts of coffee or caffeine to achieve the effects they enjoy. This means the consumer who likes three cups of coffee today to enjoy the sensations will not need five or six cups to feel the same way in a few years . This is very different from genuinely addictive products such as alcohol and many forms of illegal drugs where regular users will be inclined to increase intake to achieve the same feeling.
Secondly, withdrawal is not genuinely a challenge. Someone who wished to stop drinking coffee could just moderate their consumption downward for several days to stop drinking completely with no effects. Caffeine withdrawal usually only appears amongst a small percentage of regular coffee consumers who abruptly stop their caffeine consumption. They may experience mild headaches, irritability and nervousness from sudden deprivation.
Thirdly, as much fun as can be made of a coffee lover’s craving for a cup of coffee, there are no anti-social behaviours linked to caffeine consumption.
If for any reason you are advised to stop or reduce your caffeine intake, just reduce consumption gradually to the desired level, or to no intake at all.