What is caffeine?
Caffeine is an organic chemical and stimulant drug, used world wide. Pharmacologically, caffeine is one of a group of stimulants called methylxanthines, or xanthines, that occur naturally in some plants. In addition to mental stimulation and sharpening of motor skills, it also acts as a diuretic, removing water from the body via the kidneys; stimulates increased peristalsis in the bowel, prompting evacuation; is a potent vasoconstrictor, raising the blood pressure. All natural sources of caffeine were discovered and used in their native environments from ancient times. The buying and selling of caffeine-bearing products has been an historical stimulus to trade and caffeine remains one of the world's most popular drugs.
Beverages made from the nuts, seeds or leaves of these plants are currently major sources of natural caffeine. These include coffee, made from the seeds of the Coffea arabica plant; soft drinks, like Coca Cola, made from Kola nuts; tea made from the leaves of Thea/camellia sinensis; and mate' tea made from the leaves of the yerba mate. Cocoa, ground from seeds and used to make chocolate, contains caffeine as well as theobromine, another xanthine.
Caffeine is also extracted from these natural sources to be added back to other products as a food additive. In the USA, its use and labeling is regulated by the Federal Food and Drug Administration (FDA). Food and beverage manufacturers in the US are legally required to list caffeine on their products' label ONLY when caffeine has been ADDED to a food. Caffeine naturally present in various ingredients used in the production process is NOT required to be listed on the label. For example, chocolate naturally contains caffeine, but it usually is not listed as an ingredient in candy bars. To avoid caffeine, you must avoid natural plant sources when making food choices.
The FDA also regulates caffeine's use as a stimulant in some over-the-counter and prescription medications. Check the labels; you may see caffeine listed as an active ingredient in some stimulants, cold remedies, and various pain killers.
Why is caffeine added to foods?
American business has a history of adding substances to food and drink that are physically habit-forming or addictive in order to increase sales. This was the premise behind adding the extract of the coca leaf, or cocaine, to coca-cola when it was first developed. Since cocaine can no longer be used as an additive, caffeine, which is also habit-forming, has been substituted instead. Only after medical research shows evidence of a problem with an additive do manufacturers look for alternatives.
Which types of coffee contain the most caffeine?
First of all, caffeine content is measured in the laboratory using a 5 to 5 1/2 ounce cup of coffee or tea, just a tablespoon over 1/4th cup, but a typical serving nowadays is 10 to 12 or even 16 ounces.
The caffeine content of a standard 5 ounce cup of coffee can vary from 40-150 mg. Two influencing factors are the variety of coffee bean and where it is grown; the caffeine content is further affected by varying soil conditions, length of growing season, and time of harvest. Even coffees grown in the same general region will differ in caffeine content.
Three factors that affect caffeine levels in coffee can be modified by the consumer. These are how finely the beans are ground before coffee making and the method and length of time used for brewing the coffee.
The press method, where the water sits on finely ground coffee that is not separated from the liquid until serving, extracts the highest amount of caffeine. The drip method, with fine ground coffee, used in machines like Mr. Coffee, generally yields the next highest amount of caffeine, ranging from 110-150 mg per five ounce cup. Percolated coffee is third in caffeine, ranging
from 64-124 mg. Expresso brewing, because it allows the water to stay on the grounds so briefly, actually extracts less caffeine than the previous methods. Instant coffee is usually lower still, averaging between 40-108 mg per cup. Decaffeinated coffee is low in caffeine, but not caffeine-free. About 2-5 mg of caffeine per five ounce cup is typical.
|COFFEE BREWING METHOD|
(5 oz cup)
|CAFFEINE CONTENT (mg) |
[compiled from Consumers' Union, Food and Drug Administration, National Coffee Association of the U.S.A., and National Confectioner's Association of the U.S.]
Decaffeinated beverages are NOT caffeine free
The decaffeination process of coffee and tea effectively removes about 97% of the caffeine, leaving approximately 2-5 mg in a cup of coffee. (A regular cup of coffee contains 40-150 mg of caffeine). Decaffeinated soft drinks may also contain traces (0-.09 mg) of caffeine, compared to about 36 mg per serving in naturally caffeinated soda pop.
Is decaffeinated coffee SAFE?
Two basic decaffeination processes are allowed for coffee in the U.S.: water extraction and direct solvent extraction. In the water extraction process, the coffee beans are steamed and then soaked and rinsed, allowing the caffeine to diffuse from the beans into the water, using no artificial chemicals.
In the direct solvent extraction process, decaffeination is accomplished by direct application of methylene chloride, ethyl acetate or carbon dioxide to the coffee beans. The beans are then steamed to remove the residual solvent, dried, and roasted. Methylene chloride received a great deal of attention when it was found to be an animal carcinogen when given by inhalation.
Later studies found the administration of methylene chloride to mice in drinking water (which more closely resembles human exposure through coffee drinking) resulted in no adverse health effects. So the FDA continues to permit the use of methylene chloride to decaffeinate coffee because it has determined that any potential health risk is so low "as to be essentially non-existent" (FDA, 1985).
How much caffeine is in tea?
An average 5 ounce cup of tea (Thea/camellia sinensis) can contain 10-ll0 mg, making it the next highest source of caffeine in beverages. How much caffeine is in your cup of tea will depend upon the type of tea used, the tea leaf cut, and how long it was brewed. Tea drinkers may be interested to know that besides caffeine, tea contains another stimulant--theophylline.
|TEA BREWING EFFECT |
| CAFFEINE CONTENT (mg) |
|1 min. brew||9-33|
|3 min. brew||20-46|
|5 min. brew||20-50|
|Iced tea (12-oz. cup)||22-36|
[compiled from data supplied by Consumers' Union, the Food and Drug Administration, National Coffee Association of the U.S.A., and National Confectioner's Association of the U.S.]
Because of difference in fermentation and brewing techniques, caffeine varies by types of tea as well:
|TYPE OF TEA|
| CAFFEINE CONTENT (mg) |
What stimulant besides caffeine is in tea?
Tea also contains theophylline, another xanthine stimulant. Therapeutically, theophylline is sometimes used in the treatment of congestive heart failure, hyperactivity in children, and as a bronchial dilator in the treatment of asthma. Although caffeine is considered to be more potent, theophylline in very high doses (500-750 mg) can
have potentially dangerous effects on the central nervous system, including convulsions or seizures. An average 5 ounce cup of tea contains only about 1 mg of theophylline compared to its 50 mg of caffeine.
How much caffeine is in soft drinks?
Soft drinks have become the most heavily used caffeine containing beverage in the United States. A 12 oz. can of soft drink may contain 30-72 mg of caffeine, about the same as a small cup of coffee. Less than 5% of this caffeine is naturally occuring from the kola nut; manufacturers add the other 95%, using the extract obtained from the decaffeination process. The level of caffeine found in a particular brand is consistent from can to can because of strict manufacturing controls. Only those soft drinks containing caffeine will show it as an ingredient on the product label. To compare brand names, see the chart below. You may be surprised at how many soft drinks contain caffeine and the amount in your favorite beverage.
How much caffeine is in soft drinks?
Formulas do change, but these are the ranges in 2003.
|SOFT DRINK (12-oz. serving) CAFFEINE CONTENT (mg)
|Sugar-Free Mr. Pibb||58.8|
|Shasta Cherry Cola||44.4|
|Shasta Diet Cola||44.4|
|Shasta Diet Cherry Cola||44.4|
|Sugar-Free Dr. Pepper||39.6|
|Canada Dry Jamaica Cola||30.0|
|Canada Dry Diet Cola||1.2|
[Data obtained from the National Soft Drink Association]
Which over-the-counter medications contain caffeine?
Caffeine has been used as a medication in the West at least since the 1500's. Europeans used caffeinated beverages to treat headaches, vertigo, lethargy, coughs, and to try to prevent plague and other illnesses. In more recent years caffeine has been used to relieve fatigue; increase motor skills such as typing or driving a car; relieve migraine headaches in combination with other drugs; and as a possible treatment for hyperactive children, though most studies have failed to confirm its usefulness in this case.
In the U.S., the Food and Drug Administration regulates caffeine's use in over- the-counter medications and requires manufacturers to list caffeine as an active ingredient on each product's label. Consumers may want to carefully read the label of any over-the-counter preparation they are planning to use, as this caffeine added to the amount regularly consumed, in soda drinks or coffee, could contribute to caffeine overdose and unwanted side effects.
|OVER-THE-COUNTER PREPARATION|| CAFFEINE (mg)|
|NoDoz tablets|| 100|
|Vivarin tablets|| 200|
|Excedrin P.M.|| 0|
[Source: FDA's Center for Drugs and Biologics]
Does chocolate contain other stimulants beside caffeine?
Cocoa is ground from the seeds of the Theobroma cocoa plant (or cocoa beans) and used in making chocolate milk, hot cocoa, and various candies and sweets. It contains small amounts of caffeine, plus large amounts of theobromine, another alkaloid in the xanthine family. Theobromine is classified as a mild central nervous system stimulant and has physiological effects similar to those of caffeine, but much weaker. The average cup of hot cocoa contains about 10 mg of caffeine but over 200 mg of theobromine. A 3 1/2 ounce chocolate bar contains approximately 12 mg of caffeine and 155 mg of theobromine.