Caffeine
Caffeine: the World’s most common stimulant
More people use caffeine every day than any other psychoactive
drugs. Xanthines are the active ingredients in all these products.
Coffee has been seen as a curative for everything from measles to lust
reduction! Coffeehouses can be a place to socialize, relax, do business,
similar to a bar. The all time high of coffee consumption was 20 lbs per
person each year. Today soft drinks compete with coffee since they are
convenient and easily carried in the car, etc. In 1999 Americans were
drinking over 50 gal. of soft drinks per person, and 25 gal. of coffee. Brazil
is the primary supplier of coffee to the US, with Colombia second.
Decaffeination became popular for health reasons in the 1980s. This process
includes soaking the nonroasted beans in an organic solvent. The solvent
residue evaporates during roasting. There is also a water process but it
removes more of the coffee flavor. The caffeine removed from the coffee is
used in soft drinks such as Coke. Specialty coffee shops have spread rapidly
since the late 1980s.
Tea was also seen as a medicinal plant- as far back as 350 AD., good
for bladder ailments, headaches, stomachaches, joint pain. Tea can be
oxidized to produce black tea, or sold without oxidation (fermentation) as
green tea. Most Americans drink black tea. Iced tea was introduced at the
1904 world fair in St. Louis and is now 75% of the tea consumed. Tea has a
lower concentration of caffeine per cup than coffee. Herbal teas are popular
today, but they contain no tea and are decaffeinated. One active ingredient is
theophylline, which has a relaxing effect on the bronchi and is actually
prescribed for asthma in some cases.
Chocolate contains theobromine, and came to us from the Aztecs.
Chocolate comes from Mayan words choco- warm and latl- beverage. The
Aztecs did not sweeten it, however. The Spanish added sugar to the mix.
Theobromine has actions similar to caffeine, but is less potent.
Soft Drinks – Coca Cola was produced in Atlanta in 1886 from a
nerve tonic developed by Dr. J.C. Pemberton. IT is such a complex blend of
fruit flavors, that no particular flavor is recognizable. It was advertised as a
cure for nervous ailments- headache, pain, hysteria, melancholy. There was
some cocaine in the mix in 1903, but it was removed by 1906, after the
cocaine scandals of patent medicine at the turn of the century. Although
sugar-free and caffeine-free soft drinks are getting a larger market, the most
popular drinks are the regular colas. Coke and Pepsi cover 75% of the
market. High caffeine drinks became more popular with youth in the late
1990s, and these products advertised they would increase energy, feed the
rush. RC Edge has the most caffeine in soft drinks, half again as much as
Mountain Dew.
Over-the-counter drugs often have caffeine in them, but people
often don’t realize that is part of the active ingredient. Obvious stimulants,
such as Vivarin, may have as much as 200 mg. but many analgesics, pain
killers such as Excedrin also have caffeine, since caffeine constricts the
blood vessels in the brain and that often relieves a headache. Some diuretics
also contain 100 – 200 mg. of caffeine.
Mechanism of action
Xanthines are the oldest stimulants known. The word is Greek for
“yellow” and the residue that remains after xanthines are heated is yellow.
The primary xanthines are caffeine, theophylline (in tea), and theobromine
(in chocolate). Caffeine has the greatest effect. Theobromine has very little
effect on the CNS. Theophylline is most potent and caffeine the least potent.
Caffeine is rapidly absorbed, hitting peak blood levels within 30 min. after
ingestion. Tolerance does build up, especially in the kidneys and salivary
flow. These drinks have a diuretic effect on the body, which explains why
they are included in OTC water pills. Withdrawal effects include fatigue,
loss of energy and headaches and some depression when drinkers abstain.
Effects decline over 5 – 6 days. Caffeine is reinforcing, as it produces
pleasant, energized mood states. The way it works in the brain is by blocking
the brain’s receptors for adenosine, which produces sedation and inhibited
mood.
Physiological effects
200 mg. of caffeine (2 cups of coffee) activates the cerebral cortex
and decreases drowsiness/ fatigue. It can produce a nervous state in people
not accustomed to this stimulation. Even this amount of caffeine will disturb
sleep. It is a sign of dependence when you can get to sleep after drinking
coffee or Coke at night. At higher doses, 500 mg. heart rate and respiration
will increase. Caffeine has opposing effects on the neural system, however,
working on the heart and the medulla in the brain- the autonomic nervous
control center in conflicting ways. Continued use of high doses of caffeine
can produce an irregular heartbeat in some people.
Behavioral effects
Stimulation of the CNS is a natural effect, but this does not
necessarily improve cognitive function. IT may have beneficial short term
effects, but there occurs a tolerance that ultimately lowers academic
performance. High caffeine consumption is related to lower academic
performance overall. Caffeine will allow a tired person to work longer,
however, so there are some uses that can benefit pressured college students.
Headache can be relieved by high doses of caffeine, as it has
vasoconstrictive effects in the brain. Of course if you are withdrawing from
caffeine, you will have headaches due to dependence on caffeine’s effects on
the brain’s blood vessels.
Hyperactivity – caffeine has been used to calm hyperactive children
and it has a mild effect on attention span. It is not as effective as stimulants.
Sobering up after a drinking binge is not an effective use of caffeineit may forestall the drinker falling asleep on the trip home, but it won’t lower
blood alcohol levels. It may even stimulate aggression in a drunk.
Concerns are often described, since it is the most widely used psychoactive
drug in the world. Even most conservative religions do not prohibit caffeine
(not including the Mormons.) Testing for links to various diseases must
control for other addictive behaviors, as high coffee drinkers also smoke
more. And using reporting techniques, all forms of caffeine must be
assessed. People often do not realize how many sources of caffeine they use.
Cancer has been investigated but found no genuine link with caffeine.
Benign breast disease means non-cancerous cysts or lumps in the
breast. Although controlled studies have not found a link, individuals report
that when they stopped caffeine use, their cysts stopped developing and
improved overall.
Reproductive effects – there may be a link to infertility, difficulty
conceiving while drinking lots of caffeine. Other effects are greater risk of
miscarriage, lower birth weight in the baby.
Heart disease – in a longterm study of male medical students, they
found those who drank 5+ cups of coffee/ day were 2.5 times more likely to
suffer coronary heart disease. Coffee also seems to increase cholesterol
levels, so it may be a double risk factor for heart disease.
Caffeinism is excessive use of caffeine- and it can produce symptoms
of nervousness, irritability, shakiness, insomnia, heart palpitations,
arrhythmias and GI tract disturbances.