HOW WE TAKE CAFFEINE
COFFEES
The
amount of caffeine in a cup of coffee varies tremendously and depends on several factors.
Types of Coffee Beans
Robusta beans are often grown in Africa and may
have as much as twice caffeine as
arabica beans, which are grown in South America and the Middle East, among other places. Robusta coffees
are generally cheaper and are often
used in the mass-produced canned coffees sold in grocery stores, though the package label may not indicate what kind of
bean it is. Arabica coffees are
considered to be of
higher grade and to yield a better-tasting
cup. Although generally available, they are predominant at specialty coffee retailers and through the rapidly
growing mail-order coffee businesses.
Arabicas are also much more often sold in whole-bean form than are robustas. For purposes of
comparison, a typical cup of coffee
brewed from arabica beans generally has 70 to 100 milligrams of caffeine, whereas the comparable amount of robusta
coffee may have closer to 150 milligrams.
Method of Roasting
Dark-roasted
coffee beans contain less caffeine
and less acid than lighter‑ roasted ones. Many people think that dark-roasted coffees contain more caffeine because they often have a
more powerful taste than the lighter roasts. In fact, the additional roasting
associated with the darker product allows more time
for caffeine to be broken down in the beans.
Fineness of Grind and Method of Brewing
The method of brewing and the size of the granules
of ground coffee interact to have a significant influence on the amount of caffeine per ounce of coffee produced. The finer the grind, the
more surface area of ground coffee
comes into contact with the brewing water. This creates more opportunity for caffeine to be extracted from
the ground beans. As for brewing
method, a cup of coffee made using a drip-type coffeemaker generally has about 20 percent more caffeine than
a cup made in a percolator. French presses, or "plunger
pots," can also extract maximal caffeine levels
from ground coffee because the grounds are actually soaked in boiling water for several minutes prior to the
plunger being lowered to separate them from the water.
Espresso
Espresso is
really a different drink from brewed coffee. It is made by passing water rapidly through relatively tightly packed
coffee grounds under high pressure.
The result is that the oils and other products in the coffee are more fully
extracted than under other coffee brewing conditions, and the taste is
considerably richer than that of other coffee brews. A typical "cup" of espresso contains about one and
a half to two fluid ounces—much less
than a cup of coffee. But espresso contains more caffeine per fluid ounce than coffee does.
Thus, the amounts of caffeine in a cup of coffee and a cup of espresso
are about the same. While an average cup of coffee
brewed from arabica beans contains seventy to one hundred milligrams of
caffeine, the average cup of espresso usually contains about sixty to ninety milligrams.
Why do so many people believe that espresso
creates more of a "caffeine
buzz" than coffee does? Perhaps because of the higher concentration of caffeine in the espresso. When a drug is more
concentrated in a certain solution,
it tends to be absorbed more rapidly across the membranes of the stomach and small intestine. So, even though a
single espresso (espresso solo) may have the same or less caffeine than a cup of
coffee, its more rapid absorption can
result in a more rapid onset of the caffeine
effects and a greater feeling of
"rush." Of course, a double espresso (or espresso
doppio) contains twice as much caffeine.
Other coffee drinks, such as cappuccino, caffe latte, and
café mocha, are each generally made by adding a single shot of
espresso to other ingredients. So, the
caffeine content of these drinks should be roughly equal to that of a single espresso, though less
concentrated.
Based on this information, it is obviously impossible to
present a simple table describing the amount of
caffeine in coffee drinks. Remember that these are
broad averages based on a survey of the pharmacological and dietary literatures.
Drink
|
Milligrams
|
Dripped
robusta coffee (8 oz)
|
150
|
Dripped
arabica coffee (8 oz)
|
100
|
Percolated
robusta coffee
(8 oz)
|
110
|
Percolated arabica coffee (8 oz)
|
75
|
Instant
coffee (8 oz)
|
65
|
Decaffeinated
coffee (8 oz)
|
3
|
Espresso (and espresso-based drinks)
made from arabica beans (1.5-2 oz)
|
90
|
With the rise in popularity of specialty coffees and coffee drinks, there are lots of products to
choose from. The following table shows the caffeine content of a number of these drinks in their usual
serving sizes.
CAFFEINE CONTENT IN SPECIALTY COFFEES*
Coffee and Origin Amount Dose (mg)
Espresso coffees
Big Bean
Espresso 1
shot 75.8
2 short shots 140.4
2 tall shots 165.3
Starbucks Espresso,
regular, small 1 shot 58.1
Hampden Café Espresso 2 shots 133.5
Einstein Bros.® Espresso, double 2 shots 185.0
Brewed Specialty Coffees
Big Bean, regular 16 oz 164.7
Big Bean Boat Builders Blend, 1607 147.6
regular
Big Bean Organic Peru Andes Gold, 16 oz 186.0
regular
Big Bean French Roast,
regular 16 oz 179.8
Big Bean Ethiopian
Harrar, 1607 157.1
regular
Big Bean Italian Roast,
regular 16 oz 171.8
(grown in Brazil)
Big Bean Costa Rican
French Roast, 16 oz 245.1
regular
Big Bean Kenya AA,
regular 16 oz 204.9
Big Bean Sumatra Mandheling, 16
oz 168.5
regular (grown in Indonesia)
Hampden Café Guatemala
Antigua 16 oz 172.7
Starbucks regular 16 oz 259.3
Royal Farms regular 16 oz 225.7
Dunkin' Donuts regular 16 oz 143.4
Einstein Bros.® regular 16 oz 206.3
*Data taken from the Journal of Analytical Toxicology by permission of Preston Publications.
TEAS
Tea leaves are harvested from bushes that are grown
mostly in India, Indonesia, and Sri
Lanka. Leaves are of differing qualities, depending upon how far out on the stalk of the bush they
grow. Generally, the bud leaves, which are closest to the stalk, are considered
to be of the highest quality. The
leaves are dried and allowed to ferment, which turns them to
In
general, a cup of tea will contain less caffeine than a cup of coffee. Although there is more caffeine in a pound of
fermented tea than in a pound of coffee, that pound of tea might be used to
brew three to four times as many cups
as a pound of coffee would. In addition, the amount of tea in a "cup" is often less than the amount of coffee, by tradition. As with coffees, the amount of caffeine in a given cup may vary considerably, depending on several factors. As a general guide,
the following are cal feine ranges in
teas as found in the food science
literature:
Black tea
8 oz
8 oz
14-61
mg
Green tea
24-40
mg
Iced tea 8 oz
5-11
mg
There
are well-documented positive effects of both green and black teas on health. Studies have shown that people who
drink one or two cups of tea per day
are more likely to survive a heart
attack than those who do not drink
tea. It is not clear why there is this protective effect; nor is it clear if it only applies to heart attack survival or to
cardiac health in general. But some
scientists think the protection comes from the antioxidants contained in tea leaves. These compounds may
contribute to lowered cholesterol
levels, for example, and thus help protect the heart. It's important to know that these positive effects have not been observed for herbal teas. It seems that the tea leaves themselves may be the
source of the protective chemicals.
They may also be the source of naturally stress-reducing chemicals. A recent, well-designed study found that people who drank a beverage that contained the components of black tea daily over a six-week period were more able to manage stress than those who drank a control beverage that was
identical to the tea beverage
(including the caffeine), except that
it lacked the chemicals that are
found in the black tea leaves. The
researchers even took care to serve the
beverages cold to avoid the possible stress-reducing effects of sipping a warm
beverage. Importantly, the people who
drank the active beverage also
had lower levels of the stress hormone cortisol in their blood after stressful events, indicating that the noncaffeine components of black tea leaves can help dampen the body's physical
stress reactivity.
SODAS
The consumption of caffeinated sodas in the United
States has been on the rise for a
number of years. Some people are bothered by the gastric upset that is sometimes associated with the acids
in coffees and prefer to drink
caffeine-containing soft drinks. In general, the concentration of caffeine per ounce in sodas is considerably lower
than in coffees, but the typical
serving of soda is twelve ounces, compared to six to eight ounces for coffee. The general range of doses in soft
drinks is about twenty to fifty milligrams.
The diet drinks contain the same amount of caffeine (though sometimes more) as their nondiet equivalents.
"ENERGY" DRINKS
The term energy drink is not exactly accurate. These caffeinated drinks don't actually produce more energy, but they can
generate a feeling of alertness, and
even a solid buzz, because of their caffeine content. The concentration of caffeine in these products is often
twice as high as in regular caffeinated
sodas, though the serving sizes are smaller (about eight and a half ounces, compared to twelve ounces for a
regular soda), and most come in
smaller containers. Most of these drinks contain about 50 to 75 milligrams of
caffeine. Interestingly, although these drinks have the reputation of providing a big caffeine blast, they actually
contain about the same concentration
of caffeine as coffee—maybe even a bit less. A notable exception is "5-hour Energy," which contains about
200 milligrams in just a two-ounce
serving. These drinks also often contain any of a number of additional compounds that fall generally into the
category of "supplements," like
ginkgo biloba, taurine, ginseng, B vitamins, and sugar. We will not address these in this chapter, but some of them are
discussed in other chapters, and the
energy drinks are also discussed in the chapter on stimulants.
Although energy drinks are relatively new in the US
beverage market (Red Bull was introduced into the United States in 1997), their
sales grew 60 percent from 2008 to 2012, and in 2012 their total US sales were
more than $12 billion (up from $3.5 billion in 2005). They
have been marketed aggressively to
young people and have obviously been successful. What makes these products so
attractive as to have such a big market presence? One element of their popularity may relate to how
they are consumed. Unlike caffeinated
beverages that are hot and are generally sipped slowly, energy drinks tend to be consumed quickly, thus
leading to more rapid
is also likely that some of the many other
ingredients in these drinks
interact with the caffeine, possibly modulating its
effects. This may be
true for taurine (found in Red Bull) in
particular, though there have been
very few studies on the interaction between
caffeine and taurine.
Combining energy drinks with alcohol has also
become popular. Some
people believe that
the energy drink enhances the pleasant buzz of the alcohol and diminishes the depressant effects. 'This is
almost certainly incorrect. As we
pointed out in the "Alcohol" chapter, combining caffeine with alcohol does not make a person less impaired—it
just makes him more awake. Although this may seem appealing to someone who
wants to be drunk but not sleepy,
there is a danger. If a person feels as if he is alert and unimpaired he might feel that drinking more alcohol
is safe when in fact it may not be. In general, it is always wise to be
wary of combining drugs, particularly when
there have been few studies of their interactions. Still, the idea of combining alcohol and caffeine into one
drink led to the creation of several
caffeinated alcoholic beverages. Perhaps the best known (or most notorious!) is Four Loko, which was sold in
23.5-ounce cans and contained 12 percent alcohol and a high dose of
caffeine—quite a blast! In fact, it rapidly gained the nickname "Blackout in a Can" and became very
popular on the college drinking scene.
Obviously the use of these drinks had little to do with "energy' and everything to do with rapid and sustained alcohol
intoxication. However, after multiple
reports of alcohol-related illnesses after its use, Four 1_, oko came under scrutiny by the FDA and was banned on many college campuses. The current product contains no
caffeine but retains the alcohol, available in a range of concentrations from 6 to 12 percent.
In addition to energy
drinks, per se, there are many "energy formulations" on the market.
It can be mind-boggling to sift through all of their claims about how they provide energy and good
health, but the bottom line is that
they rely mostly on caffeine for their effects. One example is guarana, which is sold in capsule form. One
formulation on the market provides
250-milligram capsules, each of which contains about 90 milligrams of caffeine (about as much as a cup of
coffee). Guarana comes from the seeds
of a South American tree and is often described as an "herbal" energy supplement or a weight loss aid. Although
there was a time when it was thought
to increase alertness because of something specific to the plant, it is now clear that it's just the
caffeine.
Some people also think that it is a good idea to
exercise after consuming energy
drinks. Although the caffeine might make you feel alert and
energy
drinks and sodas.
Beverage Energy Drinks
|
Serving
Size (oz) |
Caffeine
(mg/serving) |
Red Devil®
|
8.4
|
41.8
|
Sobe®
Adrenaline Rush
|
8.3
|
76.7
|
Sobe® No Fear
|
16
|
141.1
|
8.4
|
none detected
|
|
Hair of the Dog®
|
||
Red Celeste
|
8.3
|
75.2
|
E MaxxTM
|
8.4
|
73.6
|
8.4
|
69.6
|
|
Amp—
|
||
Red Bull®
|
8.3
|
78
|
KMXim
|
8.4
|
33.3
|
5-hour Energy
|
2
|
207
|
Cran-Energy
|
8
|
70
|
Full Throttle
|
8
|
71
|
Monster
|
8
|
80
|
Rockstar
|
8
|
80
|
Vault
|
8
|
47
|
Carbonated Sodas
|
||
Coca-Cola® Classic
|
12
|
29.5
|
Coca-Cola Zero
|
12
|
35
|
Diet Coke®
|
12
|
38.2
|
Diet Coke®
with Lime
|
12
|
39.6
|
Caffeine-Free Diet
Coke®
|
12
|
none detected
|
8 8 Vanilla Coke® 12 29.5
Pepsi® 12 31.7
Diet Pepsi® 12 27.4
Mountain Dew® 12 45.4
Mountain Dew® Live WireTM 12 48.2
Dr Pepper® 12 36.0
Diet Dr Pepper® 12 33.8
Sierra MistTM
12 none detected
Celestr Cola 12 19.4
Sprite® 12 none detected
Seagram's®
Ginger Ale 12 none
detected
Barq's®
Root Beer 12 18.0
Pibb® Xtra 12 34.6
A&W®
Root Beer 12 none
detected
7-Up® 12 none
detected
*Data taken from
the Journal of Analytical Toxicology by permission of Preston Publications.
OVER-THE-COUNTER DRUGS
There are quite a few
medicinal preparations that contain caffeine, some in very high amounts. The
following table lists some of these.
CAFFEINE CONTENT
IN OVER-THE-COUNTER DRUGS
Brand Name Milligrams
per dose
Cold Remedies
Coryban-D 30
Dristan 16
Triaminicin 30
Diuretics
|
|
Aqua-Ban
|
100
|
Pain
Relievers
|
|
Anacin
|
32
|
Excedrin
|
65
|
Goody's Powders
|
33
|
Midol
|
32
|
Vanquish
|
33
|
Stimulants
|
|
Caffedrine
|
200
|
NoDoz
|
100
|
NoDoz Maximum
Strength
|
200
|
Vivarin
|
200
|
CHOCOLATE
Chocolate is made from the bean of the Theobroma cacao bush, which contains a unique xanthine called theobromine. An average cup of cocoa may contain as much as 200 milligrams of theobromine, but this compound is much less
potent than caffeine as
a stimulant. However, chocolate also
contains caffeine. For example, a
one-ounce bar of baker's chocolate
contains about 25 milligrams of caffeine, a five-ounce cup of cocoa may contain 15 to 20 milligrams, a cup of
chocolate chips contains about 100
milligrams, and one Foosh energy
mint contains 100 milligrams. On the
other hand, a typical eight-ounce glass of chocolate milk generally contains less
than 10 milligrams of caffeine, and one Hershey's Kiss contains only 1
milligram.
One final note about
chocolate: caffeine and theobromine may not be the only psychoactive compounds in it. A recent report has indicated that
one component of chocolate is very similar to the natural chemical in the brain
that interacts with our THC receptors—the receptors to which the psychoactive compound in marijuana binds. Although
the concentration of this compound is
quite low in chocolate (it was estimated that one would have to eat twenty-five pounds of chocolate to stimulate the receptors as much as a typical dose of marijuana), it
is possible that its presence
could supplement the natural THC-like compound in
the brain enough to produce a subtle
effect. These results have led some to speculate that the vague sense of well-being and happiness that
some people report in response to
chocolate may be related to the interaction of the subtle drug effects
associated with low-dose caffeine with those associated with activating the natural THC receptors in the brain.
TOXICITY OF CAFFEINE
Overall, caffeine is fairly safe if a healthy
person takes it in moderate amounts. The undesirable side effects that most
people experience are gastric upset and nervousness or jitteriness. As people
age, they tend to have more problems
with sleeplessness and often will limit their caffeine consumption in the afternoon and evening. Pills
containing fairly hefty amounts of caffeine, however, can result in severe side
effects in people who
load up on them to stave off sleep (procrastinating students and sleepy truck drivers, for example). It is also
important to note that while caffeine may allow you to keep sleep at
bay, sleeping is a very important biological
need that you should not ignore for long.
Children who take theophylline for treatment of asthma
can also experience toxicity if their blood levels get too high. The major
symptoms are severe gastrointestinal upset and
vomiting, extreme nervousness, and nervous system
excitability, which eventually leads to seizures if blood levels
get high enough. Remember, too, that people who have other conditions that impair their cardiovascular system
(obesity, hypertension, etc.) are more
vulnerable to anything that affects heart function.
