Nature's Pharmacopeia: A World of Medicinal Plants

Chapter 12

image

Cacao

Theobroma cacao

image

An Ecuadorian postal stamp depicting a cacao pod, ca. 1930. (Smithsonian Institution, National Postal Museum, 2011.2005.181)

The cacao plant grows as a tree, a member of the lower story of the tropical rain forest. It can reach a height of 5 to 10 meters and produces simple oval-shaped, pointed, medium-green leaves and small (1 centimeter in diameter) pinkish-white flowers directly on its trunk and mature branches (figure 12.1).1 The flowers give rise to slowly developing football-shaped pods, each maturing to a green, yellow, or red color and containing twenty to forty almond-size seeds surrounded by a mucilaginous pulp (figure 12.2). Cacao grows best in hot and humid tropical regions with consistent rainfall and a short or no dry season. It is often found in the shade of nitrogen-fixing legume trees2 or in sunken cenotes (large, deep pits), where moisture and an environment protected from harsh sun and wind exist.3

ORIGIN AND USE AMONG INDIGENOUS MESOAMERICANS

Cacao likely originated in the upper Orinoco and Amazon River basins in the modern-day South American countries of Colombia, Venezuela, and Brazil, where it was first harvested around 7000 to 10,000 years ago for the sweet and flavorful pulp shrouding the seeds, called “beans.”4 From South America, cacao was brought to Mesoamerica and spread among the numerous cultural groups in the region.5 Several species in the genus Theobroma are harvested for medicine and food, including T. cacao (the widely planted domesticated species) and T. bicolor (which grows semiwild).6 By the time of European contact in the sixteenth century, cultivated cacao was seen only in Central America and southern North America.

A growing body of archaeological evidence establishes that beverages containing cacao were consumed as early as 1000 B.C.E., and it is likely that ancient peoples used cacao pulp to produce a fermented drink, a practice that exists today among indigenous peoples.7 At some point, people learned to dry and grind the beans to produce a more flavorful beverage, facilitating its spread among the societies of the region. In time, cacao took on further cultural significance throughout Mesoamerica, along nutritional, economic, artistic, and religious dimensions.8 As the Maya civilization flourished in its Classic (200–900) and Postclassic (900–1200) periods, cacao was considered a path to the divine, a tree that connected the sky, earth, and underworld, allowing spirits to pass between all realms.9 The power of cacao resided in both its physical properties and its metaphorical associations.

image

FIGURE 12.1   Cacao: (top) tree grows to a medium height in the jungle and can be highly branched; (center) flowers arise directly from the trunk and branches; (bottom) pods turn from green to yellow or red when ripe.

Early recipes called for water; a paste of ground, sometimes roasted, cacao beans; and various additives such as maize (Zea mays), chili peppers (Capsicum annuum), vanilla (Vanilla planifolia), and other spices to produce a rich, fatty, bitter, spicy, stimulating chocolate drink. There is no doubt that the biologically active chemicals in the cacao and its additives affected consumers’ physiology in ancient times, as they do now.10 By shaking the cacao beverage in a gourd, stirring vigorously, or pouring between vessels, ancient people worked up a stiff foam they considered particularly precious: they believed it to represent the breath of the gods.11 Prepared chocolate also frequently contained achiote (Bixa orellana seeds, also known as annatto), which turned the resulting liquid red and thereby evoked the blood of sacrifice and religious tribute.12 It is the revered status of cacao that Linnaeus recognized by naming the genus Theobroma: “food of the gods.”13

image

FIGURE 12.2   Cacao beans.

Maya, Mixtec, and Aztec Mesoamerican Indians, among others, cultivated cacao and integrated it into an elaborate culture of trade, tribute, worship, and ritual. From an early time, people probably used cacao to mark important events in social ceremonies, such as marriages, funerals, and rites of passage.14 Maya vases often depict cups of frothy chocolate at the feet of rulers, and numerous artifacts show cacao beverages and seeds as royal tribute (figure 12.3).15 Cacao is also found among the burial items of the elite Maya and is represented in Mixtec funeral ritual documents.16 The detailed palace scenes on some Maya artifacts show sacks of cacao offered at the ruler’s throne, and Aztec scribes recorded that cacao was given as tribute by provincial subjects to the emperor in Tenochtitlán.17 An Aztec text demonstrates the preparation of the celebrated, foamy cacao beverage by a woman of the royal court (figure 12.4). Cacao has thus been long associated with spirituality, wealth, and power.

Cacao beans also circulated as currency among pre-Columbian Mesoamericans, used to purchase trade goods such as salt, bird feathers, animal hides, and precious stones. An early Spanish chronicler of mid-sixteenth-century Nicaragua relates that at market, a rabbit could be purchased for ten cacao beans, a horse or mule for fifty beans, and a slave for a hundred.18 Prostitutes sold their services for as little as ten cacao beans.19 There is even evidence that cacao beans were counterfeited, as detailed clay replicas have been unearthed at an ancient Maya site, and early Spanish visitors noted that some cacao beans used as money had been carefully hollowed out and packed with dirt, probably to pass off as a more valuable intact bean in trade.20 In addition to its use as currency, cacao served important roles in health.

image

FIGURE 12.3   A Mayan ruler on a throne receiving what is probably a vessel of chocolate, depicted on a polychrome vessel, 600–900. (Vessel decoration rollout © Justin Kerr, K6418, http://www.mayavase.com)

image

FIGURE 12.4   An Aztec woman preparing chocolate by pouring the liquid chocolate from a height to make it frothy. (Illustration from Codex Tudela [1553]; Museo de América, Madrid)

As a sacred plant, cacao was thought to have powers unlike those of other trees in the forest. To the Maya, cacao pods were permeated with a life-giving force, rich in sap, akin to blood.21 So revered was the cacao plant that the Aztecs believed that urinating on a cacao plant or flower resulted in retribution from the heavens in the form of a skin infection called xixiotiz.22 Chocolate, a crimson metaphor for blood, was thought to be a remedy for illnesses involving the loss of blood.23 In the Aztec herbal of 1552, a treatment “against stupidity of mind” is prescribed, by which the patient is to

drink the crushed roots of the tlatlacotic [a purgative root of unknown genus and species] in hot water, that he may vomit. A few days later let the roots and flowers of the yollo-xochitl [flowers of Magnolia glauca or M. mexicana; in Nahuatl, “heart flower”] and cacua-xochitl [flowers of Theobroma cacao] be crushed in water, and let him drink the liquor before eating, wherewith the evil humor in the chest will be largely driven out.

A cacao beverage is also listed as a restorative treatment “for relieving the fatigue of those administering the government, and discharging public offices.”24

In the folk medicine of indigenous Mesoamerica, cacao figures heavily in supernatural healing, such as in concoctions administered to patients in shaman-led rituals to appease the spirits causing illnesses such as fevers and seizures.25 The connection between cacao and social health is clear in contemporary Highland Maya indigenous ceremonies in which cacao is offered at ancestral grave sites to appeal for plentiful food and fertility, and among the Ch’orti’ of eastern Guatemala, cacao is prepared to feed the gods responsible for rain and ensure a good harvest.26 People throughout the region use cacao seeds, flowers, and leaves for health conditions as diverse as low weight, skin irritation, parasitic infection, and abdominal pain.27 Cacao’s role as a sacred, precious, medicinal plant remains at the heart of Mesoamerican life.

CACAO IN EUROPE

During the Spanish conquest of the early sixteenth century, Europeans tasted cacao for the first time. While some found the beverages produced to be bitter and unpleasant, a page of the Spanish explorer Hernán Cortés (1485–1547) lauded the Indian beverage. “He who has drunk one cup,” he wrote, “can travel a whole day without any further food, especially in very hot climates.”28 The Spaniards assimilated the natives’ use of cacao as currency by making it the means by which the subjugated paid tribute to their new European lords. Indigenous people were required to pay tribute based on the size of the parcel farmed and generally out-of-date census data, meaning that during a time of widespread European-originated epidemics, widows were forced to pay tribute for their deceased husbands and children for their ill parents. The bishop of Guatemala objected to the unfair tribute system in 1603, but it continued nonetheless.29

When Cortés visited the Aztec emperor Moctezuma, he was impressed by the importance given to the frothy, bitter cacao drink enjoyed by the indigenous nobility. As the New World conquerors prepared shiploads of exotic animals, precious metals, and jewels to present to the Spanish throne, they may have included cacao in the cornucopia of American treasure. Although the precise date that cacao first appeared at the Spanish court is unknown, shipments of significant quantity were arriving in Seville in the mid-1580s, and by the early seventeenth century, cacao was prepared in Madrid at the royal palace.30Initially, the Spaniards found this crude and bitter substance unpleasant to the palate and added sugar and cinnamon (Cinnamomum spp.) to the cacao paste.31 In this form, cacao became a trendy and popular nonalcoholic stimulating drink for society’s elite. The Spanish experimented prolifically with this new drink, adding dozens of flavorings from anise (Pimpinella anisum) to almonds (Prunus dulcis) and hazelnuts (Corylus avellana) to modify the flavor and enhance the enjoyment of their liquid cacao.32

By the seventeenth century, the cacao plantations in Central America were losing productivity, owing to a depletion of the land and a labor pool decimated by plague. To expand cacao farming and increase yield, the Spanish introduced the plant into the Caribbean islands, Ecuador, Colombia, and (by way of the Portuguese) Brazil. They also brought to the New World large numbers of African slaves to replace the dwindling indigenous plantation workers.33 Beginning in the seventeenth century, cacao gradually came under cultivation throughout the tropical band of European colonies worldwide, eventually spanning from Africa to India to Southeast Asia. Wherever cacao was grown, local people were harnessed to maintain plantations and carry out the laborious harvesting and processing operations.34 With burgeoning production and widespread commerce, knowledge of cacao spread throughout Europe during the seventeenth and eighteenth centuries. This phenomenon, coupled with the highly productive (and equally exploitative) sugar plantations in the Caribbean and Brazil, produced conditions ripe for a substantial expansion of the appetite for cacao in Spain, Italy, France, and England.35

Sweetened hot chocolate (still in a liquid form, as solid chocolate bars did not come about until the mid-nineteenth century) and hot chocolate mixed with coffee became preferred luxury drinks among the wealthy of Europe. The British politician Samuel Pepys (1633–1703) wrote in his diary in 1664 that he was “off to a coffee house to drink jocolatte, very good.”36 The British are thought to have been the first to add milk to chocolate when in 1727, Nicholas Sanders made a milky hot chocolate, and Joseph Fry established the first English chocolate factory three years later. English chocolatiers continue to excel at the production of milk chocolates, with firms such as Cadbury enjoying international renown.37

The American statesman Thomas Jefferson (1743–1826) noted the “superiority of chocolate, both for health and nourishment,” and preferred it to tea and coffee.38 In the early United States, the first cacao-processing firm was established in 1780 as Walter Baker and Company in Massachusetts; the company still produces chocolate under the name Baker’s Chocolate (although now headquartered in Delaware and part of a larger food conglomerate).39 The United States produced a number of leading chocolate manufacturers through its history, many of which have gained worldwide recognition. For example, in 1894, Milton Hershey established a confectionary in Pennsylvania; Frank Clarence Mars started a candy business in the state of Washington in 1911.40 Today, American chocolate manufacturers are among the most productive in the world.

CACAO IN EUROPEAN MEDICINE

The Europeans who first encountered cacao in the sixteenth century adhered to a traditional medical system that assigned qualities of hot and cold, wet and dry, to all medicinal substances.41 These properties, they believed, could be harnessed to promote a balance of hot, cold, wet, and dry substances in the body and, thereby, health. Interestingly, the Aztecs also considered the universe in terms of opposing forces or principles such as hot and cold, and wet and dry.42 Therefore, in addition to demonstrating the elaborate ritual symbolism and spiritual connection of cacao, the Aztecs probably taught the Spanish that cacao had cool and moist properties.43 In this way, cacao entered the Western pharmacopeia.

The Europeans speculated that cacao’s cool property should make it useful for treating fevers, especially in hot climates.44 As an energy-rich and stimulating beverage, chocolate attracted many consumers in seventeenth-century Europe, who extolled its health-related virtues. For example, a Spanish physician in 1631 recommended chocolate to improve fertility in women, aid digestion, and cure chronic coughing, jaundice, inflammation, and other illnesses.45 In England, an entrepreneur took out a newspaper advertisement in 1657 touting chocolate in vague but promising terms: “It cures and preserves the body of many diseases.”46 The Englishman Henry Stubbe (1632–1676) was even more emphatic in his praise of chocolate, relaying that it “doth more speedily and readily refresh and invigorate the bodily strength than any other sustenance whatever.”47 A French noblewoman, visiting Spain in 1680, wrote that “there is nothing better [than chocolate] for the health.”48 Over the course of a few decades, chocolate spread across Europe and Britain as a therapeutic, social beverage. But some observers considered cacao to be an unhealthy habit, particularly if consumed in excess or at inappropriate times. It seems that the compulsion to drink chocolate had presented itself frequently enough for a doctor in Seville to warn as early as 1624 that it should not be consumed more than two or three times a week and that if taken in the evening, it led to insomnia.49

THE PROCESSING OF CACAO

In the traditional method of preparing cacao, practiced in some parts of contemporary Mexico and Central America, cacao pods are harvested and the beans removed, still covered in their mucilaginous pulp. The pulp and beans are left partially to decompose by the action of natural yeasts and bacteria (in the trade, called “fermentation”) for approximately three to six days, which tempers some of the acidity in the beans and builds flavor.50 The beans are then dried under the sun.51 After roasting, the beans’ thin shells are removed and the meat of the seed (called the nib) is ground by hand on a heated stone grinding table, yielding a thick paste that can be pressed into small bricks or mixed with water and spices to produce chocolate.52 Through the eighteenth century, Europeans experimented with roasting temperatures and used mechanical grinders but otherwise made very few modifications to the ancient process they learned from native Mesoamericans.53 By the nineteenth century, however, English, Swiss, and Dutch innovators began to introduce new technologies that expanded the range of chocolate forms and flavors.

THE LANGUAGE OF CACAO

Cacao

The seeds or ground seeds of the cacao plant

Cacao beans

Cacao seeds

Cacao nibs

Broken bits of cacao seeds

Chocolate

A liquid or solid cacao-based food

Chocolate liquor

An oily paste of roasted, ground cacao beans

Baking chocolate

Solidified chocolate liquor

Cocoa powder

Ground cacao from which much of the fat has been pressed out

Cocoa butter

The fat removed from cacao beans

Milk chocolate

Milk solids, sugar, cocoa powder, and cocoa butter

White chocolate

Cocoa butter, milk solids, and sugar

The physical properties of cacao and its manufactured products give rise to a particular vocabulary to describe its multiple forms and industrial techniques of preparation, which are as much chemistry as art. Cacao beans possess a high fat content, making cacao pastes and drinks greasy. When cacao is roasted and ground, it yields a dark, oily paste known as chocolate liquor. When solidified into squares, it becomes what is now known as baking chocolate, a thick and bitter substance unpleasant to eat or drink. In 1828, the Dutch chocolate makers Caspar and Coenraad van Houten developed a process to press much of the fat from roasted cacao beans, producing a cake that was amenable to grinding into a less oily cocoa powder.54 The fat that is removed forms a dense, pale, lightly flavored substance called cocoa butter. Cocoa butter is a versatile oil, solid at room temperature, used in numerous cosmetic products (figure 12.5). In 1847, the Fry family pressed cocoa powder, cocoa butter, and sugar into chocolate bars.55Around 1875, the Swiss chocolatier Daniel Peter, with the assistance of Henri Nestlé, pioneered adding milk solids to sugar, cocoa powder, and cocoa butter to produce milk chocolate.56

To improve the solubility and mixing characteristics of cocoa powder, Dutch chocolate makers experimented with adding potassium and sodium carbonates, which are alkaline chemicals that neutralize organic acids. This process, called dutching, darkens the cocoa, improves its ability to mix with water and milk, and makes the flavor milder.57 Today, about 90 percent of all cocoa is dutched. After processing the cacao into a melted chocolate blend, most manufacturers subject the liquid to conching, in which it is mixed and ground for many hours, improving flavor and smoothness.58 During the nineteenth and twentieth centuries, confectioners refined the taste, texture, and aroma of chocolate products by improving mechanical techniques and introducing new additives.59 They also developed white chocolate, which is simply cocoa butter with sugar and other flavorings. Since it lacks cacao solids, white chocolate is not considered true chocolate.60

image

FIGURE 12.5   An unusual medical-cosmetic use of cacao in the nineteenth century: a hair pomade, ca. 1860. (Library of Congress, Prints and Photographs Division, LC-DIG-pga-05565)

MECHANISM OF ACTION

In its most commonly consumed forms, cacao contains a mixture of nutrients, including fats, proteins, carbohydrates, and other components. The substantial fat (40–50 percent in beans), digestible carbohydrate (12–14 percent in beans), and protein (14–18 percent in beans) portion of cacao account for its reputation as a calorie-rich comestible.61 Cacao also contains a variety of polyphenolic compounds with antioxidant properties, such as catechins, that have been speculated to reduce cancer risk and improve cardiovascular health. The body of literature on the clinical efficacy of cacao for these purposes is limited.62 A small-scale study suggested that dark chocolate may benefit circulatory system health by reducing blood clotting, a risk factor for stroke.63 However, few large-scale clinical trials using appropriate controls have demonstrated chocolate’s effectiveness to treat cardiovascular disease or other ailments, so health claims are premature.64

In contrast to the nutritional components of cacao with less well-understood medicinal properties, cacao produces a complex assortment of chemicals that are demonstrated active in human physiology. In addition to caffeine, which is present at approximately 0.1 percent in cacao beans, the related alkaloid theobromine amounts to about 2 percent in cacao beans (figure 12.6).65 Together, these chemicals exert a weak stimulant effect and increase heart rate.66 They are mild bronchodilators and diuretics.67

image

FIGURE 12.6   Theobromine.

The pleasure of eating chocolate may derive in part from the roles of the methylxanthine compounds theobromine and caffeine, which produce enjoyable sensations when taken in stimulating beverages such as tea and coffee.68 Part of the positive experience may also owe to the high fat and sugar content in chocolate confections. The combination of fat and sugar, with or without the chocolate stimulants, provides a certain satisfaction qualitatively different from that of coffee or tea drinking. As for the euphoria that accompanies chocolate indulgence, the one that drives some people to profess an addiction to chocolate (chocoholism), future investigations may address that phenomenon. Chocolate, either through sweetness and fattiness or in combination with its potent assortment of methylxanthines, probably triggers the release of serotonin and dopamine. Neurotransmitters of this type are responsible for sensations of reward and pleasure, and when chocolate induces their actions, this neurochemistry may produce the satisfaction so widely known.

In Mesoamerica many centuries ago, people produced a blood-red frothy cacao drink as a tribute to their gods. Since that time, the land and people of the tropics have been exploited to profit from chocolate’s worldwide appeal, and millions have drawn their livelihood from its cultivation, preparation, and sale. Cacao is at the center of dozens of national economies, deeply reliant on the world’s demand for its captivating flavor and powerful stimulant compounds. From such an odd plant, whose trunk-borne flowers give rise to strange fruits, derives one of the most satisfying psychoactive foods on earth.