United States, coffee consumption

In the United States, coffee consumption averages 4.00 X 10 gg cups per day. If each cup of coffee contains 160 mg caffeine, how many pounds of caffeine are being consumed each day ... 

Xanthines such as caffeine (1)> theophylline (aminophylline) (2), and theobromine (3) are a class of alkaloids that occur in numerous plants. The CNS stimulant activity of aqueous infusions containing these compounds has been recognized since antiquity. This has, of course, led to widespread consumption of such well-known beverages as coffee (Coffea arabica), tea (Thea sinesis), mate, and cola beverages (in part Cola acuminata). The annual consumption of caffeine in the United States alone has been estimated to be in excess of a billion kilos. The pure compounds have found some use in the clinic as CNS stimulants. In addition, caffeine is widely used in conjunction with aspirin in various headache remedies. 

The average daily consumption of caffeine for adults in the United States is about 210 mg. Coffee accounts for 60% of the total caffeine consumed in the United States, while soft drinks and tea each represent 16% of the total. In the United Kingdom, by comparison, caffeine intake is twice the American rate, and tea accounts for 72% of the British total. In Scandinavian countries, coffee is the preferred beverage. For instance, in Sweden, coffee makes up 85% of the total per capita of caffeine consumption. Finland is renowned for the practice of brewing particularly potent coffee, boiled and decanted directly from ground beans. 

Michaud DS, Giovannucci E, Willett WC, Colditz GA, Fuchs CS. Coffee and alcohol consumption and the risk of pancreatic cancer in two prospective United States cohorts. Cancer Epidemiol Biomarkers Prev 2001 10(5) 429-37. 

In the United States the level of decaffeinated coffee consumption increased more than fourfold between 1962 and 1989 and is now about 220 000 tonnes per annum. About 17% of the population drink decaffeinated coffee (the proportion increased from 15.8% to 16.7% between 1988 and 1989) and each drinker consumes about 2.4 cups per day. Consumption statistics for the period 1962 to 1989 are given in Table 5.5 and the effects of age and sex are summarised in Table 5.6. 

SOURCES AND CONSUMPTION. In the United States, about 75% of all the caffeine consumed as food comes from coffee while 15% comes from tea and the remaining 10% comes from soft drinks, cocoa, and chocolate. Additionally, many over-the-counter medications contain caffeine. Table C-1 shows the caffeine content of some sources. 

Fresh leaves of the khat bush Catha edulis Forssk.), found for example in several Afiican countries and the Arabian Peninsula, are chewed for their psychostimulant properties and evidence suggests that khat use may predate coffee drinking. The consumption of fresh leaves is based on the fact that potency diminishes drastically within two days. Correspondingly, khat use has remained endemic, but modem transportation allows for daily shipments to a variety of European countries and the United States. A large number of P-phenylethylamine derivatives have been detected but the main constituents are (S)-cathinone, (lS,2S)-cathine and (lR,2S)-norephedrine. Psychoactivity is, however, predominantly determined by cathinone and cathine (Fig. 18.6). The plant material is legally available in some countries, whereas both cathinone and cathine are controlled. (R)-cathinone has yet to be detected in leaves. 

---