Caffeine,
the most popular drug
November
20, 2004
by
Laura Dolson
What
is caffeine?
Caffeine is a substance which occurs naturally in some plants - coffee
and cacao (chocolate) beans and the leaves of the tea plant are the
most common sources. These plants are often used in beverages, or food
in the case of chocolate. Caffeine is also added to other beverages
and some medicines.
There
are other naturally-occuring compounds in the same family as caffeine
with some similar and some different effects. Theophylline is found
in tea, and theobromine in chocolate.
Why
do people like to drink beverages containing caffeine? Caffeine
is often called "the most commonly used drug in the world".
People like its stimulating effect - it makes them feel more alert.
For certain kinds of tasks, caffeine improves concentration and reaction
time.
What
does caffeine do in our bodies? Caffeine blocks the effect
of a neurotransmitter in our brains that normally works to relax us.
Also, it causes the body to secrete more of the hormone adrenaline,
the substance that "revs up" our nervous systems in a similar
way to stress. Our heart rates and blood pressure increase slightly,
as well as the other effects of a mild "adrenaline rush".
What
are the negative effects of caffeine? The negative effects
of caffeine come in three categories:
1)
Short-term effects - People who have too much caffeine can get nervous
and jittery. Their hearts may race, and their hands may shake a bit.
It may be harder to solve complex problems. They may have trouble calming
their minds and bodies down, and often have trouble sleeping. At higher
doses, headaches and stomach disturbances can occur. In very large doses,
caffeine is toxic.
2) Long-term effects - Caffeine can cause calcium loss, so unless
a person consumes extra calcium, long-term high caffeine use can lead
to osteoporosis. One study showed that teens who drink caffeinated beverages
regularly have slightly higher blood pressure. Pregnant women should
not use much if any caffeine, as it stays in the baby's system longer,
and can lead to having a baby with low weight, which in turn can cause
problems for the baby. However, the current thinking is that caffeine
does not generally lead to serious diseases like cancer or heart disease.
3) Poor health practices - This is perhaps the most risky of
the effects of regular caffeine use. Caffeine users can easily get into
the habit of drinking caffenated beverages when tired or needing a break
from work, when it would be healthier to perk themselves with a quick
walk or a short nap. In other words, it can become a crutch to make
up for poor health practices. The following are healthier ways to make
sure you keep your energy high and stay productive:
A) Get enough sleep! This is very
important for good health. If you are chronically underslept, you will
be amazed at how much better you feel with regular sleep in adequate
amounts.
B) Eat a good diet. In particular,
high sugar diets can send your body on an energy roller-coaster which
might tempt you to use caffeine to get you through the "dips".
Eat an adequate amount of protein, and a variety of vegetables, fruits,
whole grains, nuts, and legumes.
C) Get enough regular exercise.
Stay active. Walk, ride your bike, dance, or play sports on a regular
basis - anything that makes you feel good. It's easy to get feeling
"bogged down" without regular activity. If you feel like reaching
for a caffeinated drink, try putting on your favorite music and dancing
for a few minutes, or run outside and practice your soccer or other
sports skills.
Is
caffeine addictive? Yes, although it is considered to be
"mildly" addictive, because with some effort an addicted person
can "get off" caffeine and won't continue to have the same
level of cravings as many other addictive drugs.
What
does "addictive" mean in regards to caffeine? The
word "addictive" has a lot of different meanings. I am using
the term in the classic biological sense to mean that it has two distinct
properties:
1)
Tolerance - Taken regularly, the body adapts to the drug and gradually
needs more of it to achieve the same effect.
2) Withdrawal - When a person stops taking the drug, they feel
bad - in the case of caffeine, this means headaches, fatigue, and irritability.
People who are addicted to their morning coffee will feel bad (usually
groggy and somewhat grumpy) until they have had their coffee.
Caffeine
addiction can be avoided by not using caffeine too regularly, or in
large quantities, and by varying the amount of caffeine so the body
doesn't get used to it.
How
much caffeine is safe? Different bodies have different sensitivities
to caffeine, so it's difficult to say. Generally, adults are recommended
not to go over 300 mg per day. There aren't guidelines for kids in the
US, but in Canada, the recommendation is that middle school-aged kids
consume no more than 85 mg per day (less for younger children).
How much caffeine is in various beverages and
foods? This is harder to say than you'd think. If you look
at charts of this sort of thing, you will see that the amount of caffeine
in a naturally-derived product (coffee, tea, chocolate) is quite variable.
This is simply because plants are living things which vary in a lot
of ways from species to species and plant to plant. Also, the way the
beverage is prepared makes a big difference - how long the tea is brewed,
for example. Here are some averages:
| Cola Beverages |
30-55 mg/can |
| Sunkist Orange Soda |
40 mg/can |
| Minute Maid Orange Soda |
no caffeine |
| Mountain Dew |
55 mg/12 oz |
| Jolt Cola |
70 mg/12 oz |
| 7-11Big Gulp Cola |
190 mg/64 oz |
| Häagen-Dazs Coffee Ice Cream |
58 mg/cup |
| Dannon Coffee Yogurt |
45 mg/cup |
| Hershey Milk Choc Bar |
10 mg/1.5 oz bar |
| Hershey Special Dark |
31 mg/1.5 oz |
| Baking Chocolate |
35 mg/oz |
| Hot Cocoa or Chocolate Milk |
4-8 mg/8 oz |
| Coffee, drip |
90-150 mg/ 8 oz |
| Coffee, instant |
60-100 mg |
| Coffee, "gourmet" |
up to 270 mg |
| Coffee, espresso |
50-100 mg/serving |
| Tea, black |
20-60 mg/8 oz (up to 110 mg) |
| Tea, green |
10-36 mg/8 oz |
Questions
for Discussion: What
is a drug? How can we go about making decisions about substances such
as caffeine?
More
Health Articles for Junior High Students