Caffeine is the world’s most widely consumed psychoactive substance, used without significant restrictions in nearly every country on earth. Derived from certain plants, it is available in beverages such as coffee, tea, cola and energy drinks, as well as in chocolate and the medication Excedrin. Research reported in September 2005 in the New Scientist journal indicates that more than 90% of western adults consume caffeine. Given that it is nearly universal, it pays to know what it is and whether it is safe.
What Is Caffeine?
In isolation, caffeine is an odorless white powder that dissolves poorly in cold water but very well in hot water. Caffeine does not, however, occur in isolation in nature. It is present in the leaves, seeds and fruit of certain plants, where it serves the purpose of discouraging insects from eating them by acting as a natural pesticide, and of encouraging pollinating insects to return by rewarding them with its psychoactive effects.
This plant matter is not directly consumed by humans; rather, the seeds of the coffee plant (coffee beans) are roasted and ground to create coffee powder, tea plant leaves are dried and shredded to help make tea, and the kola nut undergoes special processing to make chocolate. Caffeine powder extracted from decaffeinated beverage stock is added to other beverages such as cola and Mountain Dew, as well as energy drinks and certain medications. Caffeine is also sold in special caffeine tablets.
What Does Caffeine Do to You?
Caffeine is indeed psychoactive to people, in that it affects the human central nervous system and thereby the human mind. It is a stimulant that increases alertness, reduces or staves off drowsiness, and increases respiration and heart rate, along with other, minor effects.
A very large dose of caffeine can be fatal, but the fatal dose for a normal human adult is about 10 grams, while a cup of coffee contains no more than about 175 milligrams of caffeine, so that the adult would need to consume more than 57 cups of coffee in the space of one hour in order to die from caffeine poisoning!
At lower doses over prolonged consumption, caffeine could potentially be dependency forming, and the withdrawal symptoms observed in some heavy caffeine include headaches and mood changes. Prolonged use of significant doses of caffeine can lead to tolerance in some people, so that a cup of coffee will no longer help keep them awake, and they need two cups; but this is not universal. Significantly, there is some evidence that caffeine affects pregnant and nursing women, so that, in the United States, the drugs regulator recommends that pregnant and nursing women not consume more than two cups of coffee per day.
Caffeine is also well-known for causing insomnia in some users, but not all. Contrary to popular belief, there is no convincing evidence that caffeine causes dehydration.
Is Caffeine Safe?
Medical people in most countries consider caffeine to be relatively safe for normal adults if consumed in small amounts. One to two cups of coffee per day do little or no harm and can be of some benefit, but 20 cups per day can have deleterious health effects! As with everything we put into our bodies, moderation is crucial. So enjoy that chocolate bar, but don’t eat 30 of them at a sitting.
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Author Colin McD: I am coffee lover, there is no other way around it. I dream of getting office coffee machines installed everywhere I work so that I can have it when I need it! I was also relieved to find out that even espresso’s have under 200mg per shot (well under normally), so I’m not risking the caffeine overdose! However I forgot it appeared in so many forms, so perhaps tea and chocolate will have to be reduced!