Coffee and Health
Coffee and caffeine: properties and characteristics
Coffee is -paradoxically enough- a mysterious substance. This is because - due to the large number of different substances which are formed during the roasting stage - it is subject to notable changes throughout its processing. Hence there occur remarkable changes in its organoleptic characteristics.
Furthermore, changes take place in the chemical composition of coffee during the making of the beverage. This is due to the fact water-soluble substances are extracted during processing. Among the various types of compounds -besides water and certain minerals- caffeine is obviously very important. Caffeine is also present in considerable quantities in tea, mate, guarana, cocoa and in cola nuts (which are employed in the making of some well-known carbonated beverages).
The caffeine content varies according to the species. Of the two main species -Robusta and Arabica- the first contains on average 2.2%, and the second 1.2% of it: in the roasting process, in spite of a general loss in weight, the caffeine ratio decreases rather little.
Contrary to what is generally thought, the organoleptic characteristics.of bitterness in coffee are only marginally due to its caffeine content.
Caffeine is the pharmacologically active substance causing coffee to provoke in the human body those well-known and strongly marked physiological effects that have made this beverage so widespread and so popular.
Caffeine is the substance that stimulates the central nervous system. This results in behavioural effects like increased intellectual activity and learning ability; and a briefer reaction-time to exterior stimuli.
Gastrointestinal caffeine-absorption is rapid and complete. Caffeine circulates in the body�s water and its hematic concentration reaches the highest level 15-45 minutes after ingestion.
The time necessary for the organism to eliminate from the blood half the quantity of any substance introduced into it is called "half-life". Caffeine�s half-life in a human being varies according to age, sex, hormone condition, drugs taken, and effects of tobacco.
For example, in the average adult non-smoker (and without any special pathology), coffee�s half-life is some 4-6 hours; in the case of smokers, it is 3 hours or less. It increases up to 18-20 hours during the third quarter of pregnancy, and it is about 13 hours long in the case of women taking oral contraceptives. Caffeine is biotransformed by the liver and metabolites are expelled almost completely by the kidneys and the urinary tract.
Obviously, like every other substance -water included- coffee can be contraindicated for those people affected by pathologies in which coffee should be avoided: for example ulcers, heart diseases, or hypertension.
However -for an average healthy person- there are no contraindications except for the quantities of coffee, and consequently the intake of caffeine. As the Renaissance physician Paracelsus rightly said, "Nothing in itself is poison or cure, everything depends on the dosage".
As a matter of fact, a daily amount of 3-4 small cups of coffee is not only easily tolerable -as demonstrated by many reliable researches- but it also produces beneficial stimulating effects on the neuromuscular functions; hence such popular expressions as "energy boost", "it picks me up", and so on.
The threshold value over which caffeine intake could cause trouble is 10 milligrams per kilo weight a day (that is 550 milligrams for the average woman, and 700 milligrams for the average man). In Italy, the average per capita consumption is less than 2 small cups a day. This, expressed in milligrams, gives a total of 150, far away from both 700 and 550! Professor Silvio Garattini, Director of the Istituto Mario Negri, claims that "in the quantities commonly used in Italy, the ratio of 10 milligrams for each kilo weight would be reached; in the case of a man weighing 70 kilos, by the simultaneous swallowing of 7-8 small cups of coffee, each containing 100 milligrams of caffeine (one of the highest values for a single dose of Italian coffee - espresso or moka)".
The quantity generally recommended, for a positive effect on the organism is of 3-4 coffees at most: but, naturally, the stimulating effect and its duration vary from person to person. Suffice it to say that many people don�t drink coffee at night for fear of not being able to sleep, whilst other people drink it precisely to induce sleep!
Such data are confirmed by Garattini himself in his book "Caffeine, Coffee and Health" (published by the Raven Press, New York, 1993). This volume contains the fruits of a thorough and rigorous work of collecting and reviewing the latest scientific results involving outstanding researchers from all over the world. This book, gathering together as many as 1776 bibliographic items relating to researches and observations about coffee, deals with the most relevant problems on the relationships between coffee and the different physiological functions; and among other things the effects on the central nervous system, the cardiovascular system and on the reproductive organs.
The conclusions drawn by Garattini are that "to drink coffee does not damage health as long as one remembers the rule of moderation - a rule, good moreover for everything that we eat and drink". An important chapter is that dealing with consumption, from which it emerges that, contrary to what is commonly believed, Italians with their bare two small cups a day, are not at all heavy consumers; even though, in our country, coffee is considered a sort of national beverage! Actually, the record is held by the North-European countries like Finland, Sweden and Denmark.
This discrepancy is probably due also to the different ways of making and drinking coffee: in fact in our country the "espresso" or "moka" cup is popular, mostly in the morning and after the midday meal. It is considered a sort of "strengthening elixir"! In Northern Europe, by contrast, they prefer a more diluted coffee, to be consumed like a real drink at every moment of the day.