Caffeine in the Diet

Overview & Description

Caffeine is known in chemical terms as trimethylxanthine. It acts as a stimulant on the brain.

Information

Too much caffeine in the diet may cause the following symptoms:

anxiety

diarrhea

irritability

sleep disorders
Caffeine withdrawal can cause headaches. Someone who wants to stop drinking caffeine should start by mixing regular coffee with a decaffeinated version. It's helpful to gradually reduce the amount of caffeine ingested each day.
Caffeine is one of the most thoroughly studied food constituents. Here are some recent research findings.

Caffeine may cause miscarriage or may decrease the growth of a developing fetus if a pregnant woman has more than 300 mg a day. This amount is equal to 3 cups of coffee. Pregnant women should consume less than 300 mg of caffeine per day.

High caffeine intake was associated with an increased risk for osteoporosis and bone fracture in postmenopausal women.

Men diagnosed with high blood pressure had even higher blood pressure readings after drinking caffeine.

Caffeine intake was not associated with an increased risk for coronary artery disease.
While more research is needed, there are clear reasons for limiting caffeine in some situations. Individuals should discuss their risk factors and caffeine intake with the healthcare provider.

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Functions and Sources

In what food source is the nutrient found?

Caffeine occurs naturally in foods and beverages. It is found in coffee, tea, soft drinks, cocoa, chocolate, and kola nuts. Trimethylxanthine is added to caffeinated sodas during processing. Caffeine is also added to several over-the-counter medicines to increase their effects. Some weight-loss products, pain medicines, and cold remedies contain caffeine.
The caffeine content of coffee depends on the type of coffee bean. Beans from the plant species robusta generally have more caffeine than those from the arabica species. Arabica beans generally produce a more full-bodied flavor. These beans are the ones likely to be found in gourmet coffee shops. The roasting and brewing of coffee also play a part. Contrary to popular belief, darker roasted beans actually have less caffeine. The heat literally roasts out the caffeine.
Here is the caffeine content of certain foods, beverages, and medicines:

Regular, brewed coffee (8 oz) = 40 to 180 milligrams (mg)

Instant coffee (8 oz) = 30 to 120 mg

Decaffeinated coffee (8 oz) = 3 to 5 mg

Loose-leaf green tea (8 oz) = 8 to 36 mg

Brewed American tea (8 oz) = 20 to 90 mg

Brewed imported tea (8 oz)= 25 to 110 mg

Hot cocoa beverage (6 oz) = 2 to 8 mg

Mountain Dew (12 oz) = 55 mg

Cola (12 oz) = 36 to 90 mg

Decaffeinated cola (12 oz) = 0 mg

Milk chocolate (1 oz) = 3 to 6 mg

"No Doz" regular strength (1 tablet) = 100 mg

Excedrin (1 tablet) = 65 mg

How does the nutrient affect the body?

Caffeine acts as a stimulant on the central nervous system. That means it increases the heart rate and blood pressure. The individual may temporarily feel more awake and energetic. Caffeine also acts as a diuretic, which means it works on the kidneys to excrete more urine.

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Attribution

Author:Clare Armstrong, MS, RD
Date Written:
Editor:Ballenberg, Sally, BS
Edit Date:05/31/01
Reviewer:Iris Hill, RD, MA
Date Reviewed:05/08/01