I’ve seen several hundred-year-old articles which state that coffee is bad for your health, so I was surprised to see information in a 1921 cookbook about the benefits of coffee. Here is what it said:
The stimulating property of coffee is due to the alkaloid caffeine, together with an essential oil. Like tea, it contains an astringent. Coffee is more stimulating than tea, although, weight for weight, tea contains about twice as much theine as coffee contains caffeine. The smaller proportion of tea used accounts for the difference. A cup of coffee with breakfast, and a cup of tea with supper, serve as a mild stimulant for an adult, and forms a valuable food adjunct, but should never be found in the dietary of a child or dyspeptic.
Coffee taken in moderation quickens action of the heart, acts directly upon the nervous system, and assists gastric digestion. Fatigue of body and mind are much lessened by moderate use of coffee; severe exposure to cold can be better endured by the coffee drinker.
In times of war coffee has proved more valuable than alcoholic stimulants to keep up the enduring power of soldiers. Coffee acts as an antidote for opium and alcoholic poisoning. Tea and coffee are much more readily adsorbed when taken on an empty stomach; therefore this should be avoided except when used for medicinal purposes. Coffee must be taken in moderation; its excessive use means palpitation of the heart, tremor, insomnia, and nervous prostration.
The Boston Cooking-School Cook Book (1921)