People who wish to avoid or minimise caffeine intake (see below) often use decaffeinated coffee, or coffee substitutes. One method of decaffeination is by treating the green beans (before roasting) with chlorinated hydrocarbon solvents; other methods are also used. Important coffee substitutes are chicory, and roasted cereals such as barley; although these are commonly used not as total substitutes but as “”extenders””. Under U.S. law, the addition of chicory or any other substance must be clearly stated on the label.
Caffeine is a drug that has been widely used for centuries. Its main
effect is that it is a mild stimulant of the central nervous system (CNS), helping to reduce feelings of drowsiness and fatigue. However, regular use may lead to “”habituation””; that is, no net benefit from use but, rather, a negative effect if the drug is not taken.
Besides the above-mentioned CNS stimulant effect, caffeine also temporarily increases heartbeat, increases the blood pressure, and stimulates the action of the lungs; increases basal metabolic rate (BMR), and promotes urine production; and it relaxes smooth muscles, notably the bronchial muscle. Caffeine is used in treating migraine, either alone or in combination. It enhances the action of the ergot alkaloids used for the treatment of this problem, and also increases the potency of analgesics such as aspirin. It can somewhat relieve asthma attacks by dilating the bronchial airways.
Too much caffeine can produce restlessness, nausea, headache, tense muscles, sleep disturbances, and cardiac arrhythmias (irregular heartbeats). Because caffeine increases the production of stomach acid it may worsen ulcer symptoms or cause acid reflux (“”heartburn””). Evening use of caffeine may disrupt sleep and cause insomnia.
Caffeine should be used with caution by people with heart disease and high blood pressure (hypertension), and by those suffering from the eye disease glaucoma. Caffeine medications should generally not be used in children. Many children are already consuming significant amounts of caffeine in drinks and food. In this connection, a nutritional concern is that children may choose fizzy drinks in preference to milk, thus getting “”empty”” calories at the expense of valuable nutrients.
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