caffeine

Shared by: hedongchenchen

Tags

Stats

views:: 15
posted:: 8/12/2012
language:: English
pages:: 8

Public Domain

Document Sample

Huong Le
Per: 4

Caffeine
Pre-Quiz
1. The most commonly known source of caffeine
a. Almond nuts
b. Sugar
c. Coffee beans
d. None of above

2. Caffeine is a member of the alkaloid family.
a. True
b. False

3. Caffeine is addictive:
a. True
b. False

4. Caffeine makes people
a. Improves coordination and cognitive performance
b. More alert
c. Sleepy
d. Both a and c
e. Both a and b

5. Caffeine is often added to headache medications because …
a. It helps preserve the active ingredients
b. It helps the body absorb the drugs more quickly
c. It helps keep the person awake in case of head injury
d. None of above

6. Women who get a lot of caffeine should reduce their consumption when pregnant.
a. True
b. False

7. Caffeine effects mostly on ________ in a human body
a. Brain
b. Kidneys
c. Stomach
d. All of above
8. The amount of caffeine in food products varies depending on the serving size, the type
of product and preparation method.
a. True
b. False

9. How does caffeine affect the body?
a. Increases ability to concentrate
b. Increases heart rate
c. Increases blood pressure
d. All of the above

10. Which of these over-the-counter medications contain caffeine?
a. Diuretics
b. Pain relievers
c. Cold remedies
d. All of the above

--------------------------------------------------------------------------------------------------------
Information
 Definition of caffeine

Caffeine, scientific name methylxanthine. It is a member of the alkaloid
family; a group of compounds obtained from plants whose molecules consist of nitrogen-
containing rings. Caffeine is naturally occurring in the leaves, seeds or fruits of more
than 63 plant species. The most commonly known sources of caffeine are coffee and
cocoa beans, cola nuts; tea leaves and artificially added to certain soft drinks. In its pure
form, caffeine is a fleecy white solid or long silky crystal. It is odorless, but has a
distinctive bitter taste.

 Common routes of intake

The majority of caffeine is ingested in a beverage such as coffee, tea, or soda.
Beyond beverages, caffeine is also consumed in snacks such as chocolate candy bars, or
as a component in drug medications. The amount of caffeine in food products varies
depending on the serving size, the type of product and preparation method. With teas and
coffees, the plant variety also affects caffeine content.

 Short-term effects

Caffeine stimulates the central nervous system. It generally makes people
more alert and less drowsy, and improves coordination and cognitive performance when
it is consumed in coffees, teas, soft drinks, or in tablet form. Caffeine can help people to
stay awake. If taken before bedtime it can delay the onset of sleep, short sleep time,
decrease the depth of sleep and decrease the amount of dream sleep. Caffeine cannot
replace sleep and should not be used regularly to stay awake, because this can lead to
more serious sleep disorders, like insomnia. Very large doses (10g or more) can produce
high blood sugar and urinary acid levels. Some people are sensitive to caffeine and may
experience tremors, nausea and insomnia, even when small amounts are consumed. When
combined with certain pain relievers and medicines for treating migraine headache, for
example, caffeine makes those drugs work more quickly and effectively. Caffeine alone
can also help relieve headaches. Caffeine can sometimes cause restlessness, irritability,
nervousness, shakiness, headache, lightheadedness, sleeplessness, nausea, vomiting, and
upset stomach.

 Long-term effects

Effects of caffeine on the heart can be considerable. Rapid or irregular
heartbeats can result from ingesting large amounts of caffeine. People at risk for heart
attacks might be ill advised to drink coffee or indulge in other sources of caffeine.
Caffeine intake exceeding the amount found in five or more cups of drip coffee a day
result in a statistically increased risk of cardiac arrest. Caffeine may cause problems for
people with the following medical conditions: food or drug allergies; peptic ulcer; heart
arrhythmias or palpitations; heart disease or recent heart attack; high blood pressure; liver
disease; insomnia (trouble sleeping); anxiety or panic attacks; agoraphobia (fear of being
in open places); and premenstrual syndrome (PMS). Certainly, the amounts of caffeine
used to cause birth defects in rodents exceed the usual amounts consumed by people.
Doctors were simply telling women, pregnant or planning pregnancy to keep caffeine
consumption within a cup or two of coffee a day.

 Receptors in the brain

The most important effect of caffeine is that it stimulates nerve cells,
particularly those in the brain. It appears that caffeine molecules bind to neurotransmitter
receptor sites in nerve cells, causing the continual stimulation of those cells. This
property explains the most common clinical symptoms of caffeine ingestion:
wakefulness, excitability, increased mental awareness, and restlessness. Caffeine affects
nerve tissue in the brain much more quickly than it does nerve tissue anywhere else in the
body. As a result, it will bring about muscular changes such as convulsions only with
very high doses of the drug--10 g or more, the equivalent of drinking 70 to 100 cups of
coffee in a short time.

 Adverse effects the user may experience with
prolonged use

Caffeine is a mild stimulant people differ greatly in their innate sensitivity
to caffeine. Whereas many individuals can drink several cups of coffee within an hour
and notice no effects, others may feel some effect after one serving. In sensitive
individuals, tests show that caffeine can quicken reaction time and prolong vigilance of
various demanding tasks. People who use large amounts of caffeine over long periods of
time build up a tolerance to it. When that happens, they have to use additional caffeine to
receive the same effects. Heavy caffeine use can also lead to dependence. Thus, if the
person stops using caffeine abruptly, withdrawal symptoms may occur. These symptoms
can include throbbing headaches, fatigue, drowsiness, yawning, irritability, restlessness,
vomiting, or runny nose. These symptoms can persist for as long as one week if caffeine
is avoided. Then the symptoms usually disappear.

 Tolerance and withdrawal

Tolerance is the user's body gets used to caffeine. When that happens, they
have to use additional caffeine to receive the same effects. Some coffee drinkers develop
tolerance to their sleep disrupting effects, but others apparently do not. Withdrawal
symptoms including headache, irritability, inability to concentrate, drowsiness, insomnia,
and pain in the stomach, upper body, and joints may appear within 12 to 24 hours after
discontinuation of caffeine intake, peak at roughly 48 hours, and usually last from one to
five days. Caffeine tolerance develops rather quickly, and symptoms of caffeine
withdrawal include fatigue, drowsiness, headache, depression, irritability, difficulty
concentrating, insomnia, nausea, vomiting and muscle pain or stiffness.

 Brief history of caffeine

People have enjoyed caffeinated beverages for thousands of years around the
world. Many anthropologists believe that caffeinated beverages may use date back to the
Stone Age. Coffee originated in Ethiopia and later introduced to Arabia and the rest of
the east. By the middle Ages, coffee was a popular drink of Muslims. In 1573 coffee was
introduced to the Europeans. Tea was introduced later in 1657 and became very popular
to the people of Europe. Revolutionary Americans made a nationwide switch from tea to
coffee as the caffeinated drink of choice in the eighteenth century. Near the end of the
19th century cola products started to appear around the world and became one of the
largest caffeine drinks. The world's first caffeinated soft drinks were created in the 1880s.
In 1958, the American Food and the Drug Administration (FDA) as being “Generally
Recognized As Safe” (GRAS) recognized caffeine. As of 2012, the American Heart
Association stated that moderate consumption of caffeine was not harmful to healthy
individuals.

 Myths or concerns about caffeine

Although caffeine is considered a mild stimulant, it’s not addictive, according to
the American Journal of Drug and Alcohol Abuse. But there are some facts prove that
caffeine is addictive. For example, some people may feel headache, restlessness or
irritability if they skip their morning cup of coffee or certain time during the day. This
fact would be a concern because people have different level of caffeine. Thus, it depends
on the user, some people would be fine if they don’t drink coffee for one day or more, but
some people would not be well if that happens to them.
----------------------------------------------------------------------------------------------------------------------------- ----
Post Quiz
1. The most commonly known source of caffeine
a. Almond nuts
b. Sugar
c. Coffee beans
d. None of above

2. Caffeine is a member of the alkaloid family.
a. True
b. False

3. Caffeine is addictive:
a. True
b. False

4. Caffeine makes people
a. Improves coordination and cognitive performance
b. More alert
c. Sleepy
d. Both a and c
e. Both a and b

6. Women who get a lot of caffeine should reduce their consumption when pregnant.
a. True
b. False

7. Caffeine effects mostly on ________ in a human body
a. Brain
b. Kidneys
c. Stomach
d. All of above

8. The amount of caffeine in food products varies depending on the serving size, the type
of product and preparation method.
a. True
b. False

9. How does caffeine affect the body?
a. Increases ability to concentrate
b. Increases heart rate
c. Increases blood pressure
d. All of the above

10. Which of these over-the-counter medications contain caffeine?
a. Diuretics
b. Pain relievers
c. Cold remedies
d. All of the above

--------------------------------------------------------------------------------------------------------
Bibliography
http://ic.galegroup.com.proxy.elm4you.org/ic/suic/ReferenceDetailsPage/Reference
DetailsWindow?displayGroupName=Reference&disableHighlighting=false&prodId=S
UIC&action=e&windowstate=normal&catId=&documentId=GALE%7CCV264403037
0&mode=view

http://ic.galegroup.com.proxy.elm4you.org/ic/suic/ReferenceDetailsPage/Reference
DetailsWindow?displayGroupName=Reference&disableHighlighting=false&prodId=S
UIC&action=e&windowstate=normal&catId=&documentId=GALE%7CCV219150020
7&mode=view