Caffeine. It's a naturally-occurring alkaloid that acts as a pesticide in the plant world, killing insects that would otherwise eat a plant's fruits and keep it from reproducing. For humans, it is a central nervous system stimulant that fends off fatigue and restores alertness. It has several medical uses, including the treatment of headaches and the stimulation of breathing in people with sleep apnea.
Humans found caffeine on their own, and they found it all over the world: Africa, Asia, South America, North America. Europeans may not have had a natural source of caffeine until Marco Polo brought tea back from China; this would take more research time than I have this morning, so if you know about this, please share in the comments section.
Anyway, I foolishly gave it up for a while a couple of years ago, and have come back to it like a long-lost friend. Here are five natural sources of caffeine, brought to us by a loving creator.
1. Tea. The longest-documented human relationship with caffeine belongs to tea, the leaves and buds of Camellia sinensis and all its variations. Except for water, it is the most widely-consumed beverage in the world. Chinese records of tea go back a thousand years B.C., and Indian writings about tea go back at least to the Ramayana (c. 500 B.C.). England, which loves its tea with an irrational passion, didn't have it until 1662, when the Portuguese princess Catherine of Braganza married King Charles II. Even then, it took one of the earliest organized advertising campaigns to bring tea to the masses, starting around 1690, because the East India Company needed to bring something back in their ships after they'd dropped off their British-manufactured textiles and goods.
2. Coffee. A testament to the creativity of human beings: coffee is a drink made from the roasted, ground, brewed seeds of the berries of the coffee plant (genus Coffea). Tea is easy to understand; leaves fell in a jug of water, people drank the water anyway, it was tasty and stimulating, and the world changed. But coffee? How did people figure that out? Coffee seems to have originated in Ethiopia, and was first documented by Muslim scholars in Yemen in the 15th century. Islamic monks prized it for its appetite-suppressing properties. It reached Turkey in the next century, and from there went to Italy. In 1600 Pope Clement VIII declared it a "Christian drink," which might do a little to balance out his antisemitism and the fact that he had Giordano Bruno burned at the stake. No one's all bad . . .
3. Cocoa. The cocoa bean, native to South America, was used as currency among tribes before the arrival of the Europeans. Cortes' scribes recorded that Moctezuma II, Emperor of the Aztecs, drank no beverage but chocolate, which was not sweetened but was flavored with spices and vanilla and whipped to a froth. Chocolate doesn't have nearly as much caffeine as coffee or tea, which might be why Moctezuma was reported to drink as many as 50 cups a day. The Spaniards brought it back to Europe with them and added sugar, creating new opportunities for dentists to this day. The Spaniards also brought the tree to the West Indies and the Philippines; cocoa grows within a narrow climate band above and below the equator.
4. Kola nut. Kola nuts come from a group of trees related to the cocoa trees, and native to the tropical rainforests of Africa. They are not ground or brewed, but chewed, and their red-purple color can stain the teeth and mouth. Their flavor is naturally bitter, but Westerners know it as the distinctive taste of Coca-Cola.
5. Guarana. The guarana plant is actually part of the maple family, but while its cousins have sweet sap, the guarana has a high-powered berry with twice the caffeine content of a coffee bean. Guarana is the most popular source of caffeine in modern-day South America, the base of soft drinks and tea. Guarana's becoming more popular in the United States, too, and you can even try something called Perky Jerky, which is — yes — dried meat infused with guarana. I'm not ready for that yet, but if and when I ever make that Antarctic expedition, Perky Jerky's coming with me.