Sources of Caffeine

Tea (6 oz. Cup)
Black Tea 25-110 mg
Oolong Tea 12-55 mg
Green Tea 8-16 mg

Coffee (8 oz. Cup)
Brewed 135 mg
Instant 60-100 mg
Decaffeinated 1 mg

Sodas (12 oz can)
Coke 46 mg
Pepsi 38 mg
Jolt 59 mg
Mountain Dew 52 mg
Surge 52.5 mg

Other
Chocolate bar (50 gm) 20 mg
Cocoa (5 oz.) 2-20 mg
Hot Chocolate (250 ml) 4 mg
Vivarin (1 tablet) 200 mg
Espresso Drinks
Latte 70 mg
Mocha 80 mg

Note: The above figures are approximations based on industry averages.

Effects on You

Brain
Caffeine affects the same part of the brain as nicotine and other stimulants and it works in the following way:
• Binds to substance-receptors and acts as a stimulant to the central nervous system by altering messages delivered by the substance-receptors
• Alters function of the blood vessels in the head and muscles of the body

Body Tissues
Caffeine reaches all body tissues within five minutes to increase:
• Body temperature and breathing
• Urination
• Gastric acid concentration in the stomach
• Alertness

Metabolism
Caffeine affects metabolism by:
• Decreasing iron and calcium absorption
• Increasing the level of circulating fatty acids
• Does not accumulate in your bloodstream or anywhere in the body
• Filtering out through the urinary tract by the kidneys

Addiction
Many people believe they are addicted to caffeine when actually they are not. What they are experiencing is a psychological dependency, meaning there are no physical reasons for causing their bodies to require or need caffeine. You are addicted if you have:
• Built-up a tolerance to the drug
• Experience symptoms of withdrawal
• Consume even if it may aggravate medical problems

If you are planning to quit, gradually decrease your dosage to avoid these after-effects:
• Fatigue
• Irritability and mood swings
• Restlessness
• Anxiety
• Sluggishness

Health Concerns
• Caffeine presents no significant health hazard from normal consumption provided other lifestyle habits (diet and alcohol consumption) are moderate.
• Caffeine may increase alertness in tired individuals and enhance performance of certain tasks, but it depends on the sensitivity of the person.
• Many people have hypersensitivity to caffeine and develop such problems as stomach discomfort, insomnia, headaches, and irregular heartbeats.
• Those with ulcers or irregular heartbeats may be advised by doctors to abstain completely from caffeine consumption.
• For most people it is safe to consume up to 600 mg/day, but check with your physician.

Caffeine Intoxication
Caffeine intoxication is a caffeine-induced disorder that may occur with as little as 100 mg/day depending on a person’s sensitivity. Symptoms include:
• Restlessness
• Flushed face
• Insomnia
• Gastrointestinal complaints
• Nervousness or excitement

Large doses can cause rapid heartbeats and convulsions. A fatal dose of caffeine is defined as 5,000 mg (or the equivalent to 40 strong cups of coffee).

Long-Term Effects
More than 8 or 9 cups of coffee a day may cause:
• Chronic insomnia
• Persistent anxiety
• Depression

Although caffeine has not been proven to cause birth defects, pregnant women are advised to reduce caffeine intake to prevent possible health problems in themselves and their babies. Caffeine is not listed in the Food and Drug Act as a restricted drug and there are no laws prohibiting the use of products containing caffeine.

Sources cited:
• The Stash Tea Company
• Tiffany Powell, Chemistry 1, Fall 1997.
• Saarloos, Sabastian. “Caffeine: Chemically and Physically.”
• Government of Newfoundland and Labrador, Department of Health and Human Services.
• Rapaport, Jennifer. "The Buzz on Caffeine-Charged Drinks" Self May 1998.

For more web nutrition information check out these sites:

Hot Topics in Nutrition
www.cspinet.org

Soy Nutrition
www.talksoy.com

Nutrient Analyses
www.nal.usda.gov/fnic/foodcomp

Alternative Medicine
www.altmedicine.com

Sports Nutrition
www.dietsite.com

Eating Disorders
www.medainc.org

General Nutrition
www.navigator.tufts.edu