February, 2000: Brazil (Amazon Region)
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Chocolate tree. (Photo © 1999 Erica Kipp.)
From the upper Orinico River region of the Amazon rain forest comes Theobroma cacao, the source of cacao seeds from which we derive cocoa butter and chocolate. The name Theobroma comes from Greek, meaning "food of the gods." Cacao is the term used to describe the plant and its raw products, while chocolate and cocoa denote the products after processing. Besides chocolate and a multitude of other uses, there is growing medical interest in T. cacao because it contains certain plant flavonoids that have the potential to control cell and tissue damage in humans.
T. cacao belongs to the Sterculiaceae, a family whose members are usually trees or shrubs that tend to grow in warm, tropical locations. Many members of this genus are midge-pollinated and monkey-dispersed. The seeds of Theobroma are dried, roasted, and processed to yield chocolate, and the pulp surrounding the seeds is also edible. The earliest evidence of chocolate consumption is based on cacao residue in cooking tools dated at about 480 A.D. However, scientists believe the pulp was eaten fresh or blended into a beverage well before the roasting process was developed. Carved words and pictures on special pots uncovered in archaeological sites suggest that they were used to produce chocolate products for the Mayan nobility. The Aztecs consumed a cold beverage made by combining corn, cacao seeds, water, chilies, and other spices. It was believed to be an aphrodisiac. Spanish colonists in Central and South America eventually refined this bitter beverage by leaving out the chilies, adding sugar, anise, and cinnamon, heating it to improve the texture, and serving it warm. As the demand for chocolate products increased after European colonization, the chocolate tree was cultivated on large plantations. In Europe, only the wealthy were able to enjoy the early chocolate products because the cocoa seeds had to be imported. Evidence indicates that cacao seeds were used as currency in the Yucatan until 1850 and were still considered valuable until about 1923.
In addition to chocolate products, a wide range of ethnobotanical uses are associated with Theobroma cacao. The fruits, seeds, leaves, and bark have been used medicinally to treat listlessness, coughs, burns, and snakebites. They have also served as diuretics and as a base for suppositories; in fact, much of the cocoa butter produced even today ends up in suppositories. In all, more than 700 compounds are produced by the fruit, including caffeine, theobromine, theophylline (considered a muscle stimulant), and plant flavonoids known as catechins.
Historically, plant flavonoids have been used as a source of dyes because they are responsible for brilliant pigments such as anthocyanins. But catechins are antioxidants, a highly desirable group of substances that tend to neutralize the damaging oxygen free radicals attacking healthy cells in our bodies. A free radical is a molecule containing an oxygen atom that is missing an electron, which it seeks to replace by taking one from another molecule. The number of free radicals in the body is increased by such factors as radiation, poisons, cancer, and heart disease. Vitamin E, vitamin C, and beta-carotene also have antioxidant properties and are commonly taken to supplement the body's natural antioxidant production. Unfortunately, natural production wanes with age and leaves the body increasingly vulnerable as time goes on. Originally, catechins were referred to as "tea flavonoids" because they are the main component in tea, where their role in slowing the development of cancer and heart disease has been studied. But according to Dr. Ilja Arts of the National Institute of Public Health and Environment in the Netherlands, the catechin content of chocolate is four times that of tea--great news for chocoholics! The institute's study also revealed that dark chocolate has the highest catechin content, followed by milk chocolate and then tea.
At a meeting of the American Chemical Society, Dr. Lester Mitscher of the University of Kansas reported on one test that revealed catechins as 100 times more potent than vitamin C in arresting oxidative damage to DNA and 25 times more effective than vitamin E. The three most prevalent catechins revealed in the experiments by both Dr. Arts's group in The Netherlands and Dr. Mitscher's group at the University of Kansas are epigallocatechin gallate (EGC), epigallocatechin (EGCG), and epicatechin gallate (ECG). Although these specific catechins may not become household words any time soon, the researchers noted that there are different concentrations of each of these catechins (and others) in chocolate and tea. These findings may fuel further study to determine which is the most beneficial catechin (or combination of catechins) and what concentration is required to elicit noticeable antioxidant effects.
Perhaps the old Dutch habit of eating a chocolate cookie with a cup of tea is more than just a pleasant way to end the day. It's a way to enjoy the food of the gods and get a healthy dose of catechins at the same time.
References, Websites, and Further Reading
I.P. Arts, P. Hollman, and D. Kromhout, "Chocolate as a Source of Tea Flavonoids," The Lancet 354(9177), 7 August 1999.
Mabberley, D. 1997. The plant book. 2d ed. New York: Cambridge University Press.
"Yet Another Reason to Eat Chocolate, New York Times, 10 August 1999,
Tuesday science edition.
Report by Arts et al. in The Lancet on chocolate as a source of tea flavonoids
Science News Online: Food for Thought
International Cocoa Organization
Stern, Introductory Plant Biology, 8th Edition
Chapter 2: The Nature of Life
DNA, pp. 14, 27
Chapter 3: Cells
Plastids, chromoplasts, and anthocyanin pigments, p. 37
Chapter 8: Flowers, Fruits, and Seeds
Fruit and seed dispersal, pp. 139-42
Chapter 11: Growth
Vitamins, pp. 188-89
Chapter 13: Genetics
DNA (structure), pp. 228-29
Chapter 23: Flowering Plants
Pollination, p. 421
Chapter 24: Flowering Plants and Civilization
Photo of chocolate tree and fruit, p. 435
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