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What is caffeine?
Caffeine is a natural stimulant found in a variety of plants. It is a member of the xanthine group of chemicals, which also includes theophylline, an ingredient used in asthma medications, and theobromine, found in tea and cola drinks.
The first verifiable use of caffeine was more than 2,000 years ago and involved Ethiopian tribesmen who ate a mixture of raw coffee beans and fat. It is believed, however, that plants containing caffeine may have been enjoyed as long ago as prehistoric paleolithic times.
Why is caffeine important to nutrition?
Caffeine has no real nutritional role, but millions of people worldwide insist they "can't get started" without a morning cup of coffee. To these people, it is, indeed, important. Caffeine acts primarily as a
Good sources of caffeine
- Coffee.
- Tea.
- Colas.
- Chocolate.
- Cocoa.
- Many painkillers and other over-the-counter medications.
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stimulant. It also affects many organs and bodily functions, including:
Central nervous system.
- Counters drowsiness and fatigue.
- Promotes clear thinking and concentration on a short-term basis.
- Causes some nervous agitation or feelings of jitteriness when used in excess.
Cardiovascular system.
- Speeds up the heartbeat.
- Opens up (dilates) peripheral blood vessels.
- Increases vascular resistance in the blood vessels to the brain. This action explains why caffeine helps forestall a migraine (vascular) headache if it is taken early enough.
Digestive system.
- Promotes increased secretion of stomach acid.
- Helps speed passage of stool by relaxing colon muscles.
Urinary system
- Increases flow of urine by
acting as a diuretic.
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- Causes bladder irritation.
Muscles.
- Relaxes smooth muscles.
This action explains why
caffeine and other xanthines (especially theophylline) help overcome an attack of asthma.
How much caffeine do I need?
Since caffeine is not an essential nutrient, there is no nutritional need to consume any.
What happens if I don't get enough caffeine?
Caffeine is habit forming. If a person regularly consumes large amounts of caffeine and then suddenly stops, he or she is likely to experience mild withdrawal symptoms. These include headache, irritability, a feeling of nervousness, and possible tremors or shakiness.
What happens if I get too much caffeine?
Consuming large amounts of caffeine can lead to a condition called caffeinism, which is sometimes mistaken for anxiety or panic attacks. Since caffeine is a stimulant, excessive amounts can cause insomnia, palpitations, jittery nerves, and in some people, feelings of anxiety. Consistently drinking more than 7 or 8 cups of coffee a day also has been linked to a rise in levels of blood cholesterol.
For most people, however, consuming caffeine in moderate amounts is not harmful. Most people enjoy the stimulant effects of coffee or tea, and there has been no conclusive evidence that moderate caffeine consumption causes long-term harmful effects. The stimulant effects of caffeine increase with dosage, so drinking more than 2 or 3 cups of coffee per day is not recommended.
Parents are advised to limit children's consumption of colas and other soft drinks that are not caffeine-free. People with the following conditions should cut down or, preferably, eliminate their caffeine consumption:
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- Peptic ulcers. Caffeine increases the flow of gastric acids, thus exacerbating an ulcer. Decaffeinated coffee and dark roast coffees are also acidic, but may be less irritating to the stomach.
- Irritable bowel syndrome. Caffeine can promote diarrhea and other intestinal problems by irritating the lining of the digestive tract and adversely affecting the smooth muscles.
- High cholesterol levels. Recent studies show heavy caffeine consumption can raise levels of cholesterol in the blood.
- Pregnancy. There are indications that high doses of caffeine may increase the risk of miscarriage and possibly harm the fetus.
- Breast feeding. Nursing mothers should also moderate caffeine intake. Caffeine is passed to the infant through the mother's milk and may result in wakefulness and irritability.
- Heart-valve disease. Caffeine speeds up the heart rate and may exacerbate cardiac arrhythmias.
Should I take caffeine supplements?
Nonprescription caffeine pills are often used by students studying for exams and people who work at night. Excessive use of these pills should be avoided, especially by persons who have medical conditions that are made worse by caffeine.
Advice about caffeine
- If you are trying to cut down on caffeine but don't want to give up the pleasure of coffee, tea, colas, and other sources, try switching to decaffeinated beverages.
- If the acids in either regular or decaffeinated coffee cause gastric irritation, try drinking a darker roast of coffee such as Viennese or French roast, which contain less acid and caffeine than regular coffee.
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