A sprig of Paraguayan sweet herb (Stevia rebaudiana) and sugar lumps. Stevia is a noncaloric herbal sweetener that is available in many health-food stores.
Some herbal alternatives to sugar and artificial sweeteners are well-known outside the United States, yet they aren’t readily available to Western consumers. Here is an update on what we know about the sweetening herbs and their status with the U.S. Food and Drug Administration.
A sweet tooth is the downfall of many a waistline, yet the demand for sweetness in foods is so pervasive that commercial food products ranging from cereals to spaghetti sauces are laced with sugar in its various forms, including that from processed sugarcane, sorghum, corn syrup, sugar beets, and sugar maple. Such additives may make the food taste good, but they also contribute “empty” calories that can in time add up to unwanted pounds.
Artificial sweeteners such as saccharin and aspartame offer calorie-free alternatives, but they have drawbacks. Saccharin has an aftertaste, and aspartame can’t be heated and has a short shelf life. In addition, saccharin has been shown to cause cancer in laboratory animals, although that finding as well as the health risks associated with aspartame are being debated.
The sweet tooth isn’t a 1990s phenomenon. In earlier times, long before the advent of processed sugars and artificial sweeteners, people of many cultures satisfied their craving for sweets with fruits such as dates, figs, and grapes. Ancient civilizations also recognized the sweet properties of many herbs. Modern scientific technology has isolated more than seventy-five sweetening agents that come from plants. Today, a few of these herbal sweeteners are as common as sugar in non-Western countries such as Japan. They aren’t readily available to Western consumers, primarily because insufficient evidence has been gathered to convince the U.S. Food and Drug Administration (FDA) of their safety. However, the appearance of noncaloric natural sweeteners for the Western market is likely within the next few years.
Licorice (Glycyrrhiza glabra) is a Eurasian perennial herb of the pea family (Leguminosae). Its roots, which are wrinkled and brown on the outside and yellow on the inside, contain glycyrrhizin, a compound that is 50 to 150 times as sweet as cane sugar.
The earliest written reference to using licorice is found in the Codex Hammurabi, a cuneiform manuscript from Bronze Age Mesopotamia written about 1750 b.c. Licorice was known as Scythian root to the Greek naturalist Theophrastus (circa 372– circa 287 b.c.), from the legend that Scythian warriors could go for twelve days without drink when supplied with licorice root and mare’s-milk cheese. If you have ever sucked the juice from a licorice root, you probably were impressed, as Theophrastus was, with its smooth, sweet taste.
Egyptians living in about 1300 b.c. prepared a licorice drink known as mai sus, and licorice is still an ingredient of soft drinks during the Islamic holy month of Ramadan. Grocer-apothecaries of the Middle Ages were probably the first to combine licorice juice with honey and sugar, and extruded licorice sweets were available in the Netherlands toward the end of the seventeenth century. Modern licorice candies date from the Pontefract cakes made during the eighteenth century by the chemist George Dunhill of Pontefract, England, from licorice root extract, molasses, sugar and flour, but today’s candies are flavored with anise oil (many people confuse anise and licorice) and sometimes peppermint and laurel oils instead of licorice, and contain wheat flour, gum arabic, gum tragacanth, and gelatin, with carbohydrate sweeteners substituting for glycyrrhizin.
Eating large amounts of licorice can produce headaches, water retention, and imbalances of sodium and potassium. The elderly and anyone with high blood pressure or heart, kidney, or liver disease should avoid licorice-flavored products altogether.
Around the world, manufacturers use extracts of licorice roots and stolons (horizontal runners that grow from the vertical taproot) in baked goods, dairy and meat products, sauces, gelatins, chewing gum, cough remedies, plug and pipe tobacco, beer and other beverages, and candies. In the United States, the FDA includes licorice root extract on its Generally Recognized As Safe (GRAS) list as a flavoring agent but not as a sweetener. An application to the FDA for its approval as a sweetener was turned down for lack of evidence of its safety. Spain, Turkey, Greece, and countries of the former Soviet Union supply licorice root to the U.S. market.
Paraguayan sweet herb
The leaves of the perennial herb Stevia rebaudiana, a member of the aster family (Compositae), have been known to the Guarani Indians of Paraguay by various names, all loosely translated as “sweet herb”. In the United States, the plant is generally referred to as stevia, but because many other plants share that common name, the best way to ensure that you have the right species is to specify it by its botanical name.
Since pre-Columbian times, the Guarani have used the herb to sweeten bitter drinks such as maté, made from the leaves of holly tree (Ilex paraguariensis). In 1931, French researchers discovered the source of its sweetness, a compound that they named stevioside. We now know that stevioside is one of eight compounds in the leaves that have sweetening properties and that it comprises 6 to 22 percent of the dried leaves and 1 to 4 percent of the dried flowers. The other sweet compounds comprise much less. No other species of Stevia has leaves that are as intensely sweet as those of S. rebaudiana. Stevioside is 200 to 300 times as sweet as sucrose (the simple sugar processed from sugarcane and sugar beets) but contains virtually no calories. The sweetness of the leaves depends upon how the plant is propagated, the number of hours of sunlight the plant receives daily, and soil conditions. Canadian researchers found that plants spaced 12 inches in rows 12 inches apart yielded 2,677 pounds per acre of leaves with a stevioside content of 10.5 percent, or 281 pounds of stevioside per acre. If stevioside is estimated to be 210 times sweeter than sucrose, this yield of stevioside is equivalent to nearly thirty tons of sugar per acre.
As a sweetener, stevioside is in common use in Japan, China, North and South Korea, Israel, Brazil, and Paraguay; most of the commercial culture of stevia is done in South Korea, Japan, and Taiwan, where several stevia products are sold, including Stevix and Steviosin, trademarked names of Tama Biochemical of Japan. In Japan, stevia extracts and stevioside are used to sweeten pickles, fish and dried seafoods, meat pastes, soy sauce, bean paste products, fruit-flavored drinks and other beverages, ice cream, and chewing gum. In the United States, the leaves of S. rebaudiana have been used to flavor herbal teas, and several major U.S. corporations use stevia to sweeten products sold in other countries.
Stevioside hasn’t proven toxic in tests that have been done on laboratory animals, and no indications exist that it is carcinogenic in humans, but in May 1990 the FDA issued an import alert on S. rebaudiana. It was lifted in 1995.
Aztec sweet herb
Aztec sweet herb (Phyla scaberrima, formerly Lippia dulcis), a perennial herb of the verbena family (Verbenaceae), was called tzonpelic xihuitl, “sweet herb”, by the Aztecs. The earliest written record of medicinal herbs used by the Aztecs is the Libellus de Medicinalibus Indorum Herbis, an herbal written in Nahuatl by the Aztec physician Martín de la Cruz and translated into Latin by Juannes Badianus in 1552. In this work, Aztec sweet herb is called Tzopelicacoc.
In Mexico, a decoction of Aztec sweet herb is used to treat a variety of ills. In the late nineteenth century the U.S. pharmaceutical company Parke, Davis included it in a concentrated tincture used to treat bronchitis.
The sweet taste in Aztec sweet herb comes from hernandulcin, a compound found in the stems, leaves, and roots that is about three times as sweet as sucrose but somewhat bitter and with an aftertaste. Although hernandulcin itself has not been shown to be toxic, the herb’s essential oil contains 53 percent camphor, and the raw leaves also are scented with it. Camphor is toxic, particularly for small children. Ingesting it can cause nausea, vomiting, depression of the central nervous system, and coma. Additionally, the traditional use of the herb in Mexico to promote menstruation alludes to its potential to induce abortion, possibly because of the camphor. The herb is not on the FDA’s GRAS list.
Katemfe (Thaumatococcus daniellii) is a common perennial herb of the arrowroot family (Marantaceae) throughout the West African rain forest from Sierra Leone to the Congo. It also grows in East Africa in the Sudan and Uganda. Broad, dark green oval leaves are borne on stems up to 10 feet tall arising from rhizomes. The fleshy fruit, developing from a spike of pale purple flowers formed at the base of the stems and also arising from the rhizomes, matures to a dusty red; each of the one to three hard black seeds is surrounded by an intensely sweet, jellylike sac, or aril. It yields a mixture of sweet proteins, notably thaumatin, which by some estimates is about 1,600 times as sweet as sucrose. Thaumatin has about the same caloric value as other proteins, 4 calories per gram, but so little thaumatin is needed for sweetening that its caloric contribution is negligible.
Thaumatin inhibits dental caries, is safe for diabetics, and is nontoxic. However, thaumatin loses its sweetness when it is heated or at a pH balance below 2.5. It takes longer for taste buds to perceive thaumatin’s sweetness than to perceive that of sucrose, however, and researchers are working to eliminate its lingering sweet aftertaste.
Talin, a commercial thaumatin preparation, is manufactured in England from frozen arils shipped in from Africa. However, the supply of thaumatin is limited because katemfe doesn’t grow outside of its native habitat, even in controlled greenhouses. Thaumatin has been approved for use as a sweetener in many countries. The FDA has approved it for use in chewing gums, and in 1995, the U.S. Patent Office issued a patent for a recombinant form of thaumatin.
More sweets on the horizon?
Serendipity berries: In 1969, researchers reported that the grapelike fruits of the West African vine Dioscoreophyllum cumminsii, a member of the moonseed family (Menispermaceae), were surprisingly sweet. Known in Sierra Leone as ekali-bonte or kaligbonde, this plant is native from Guinea to the Cameroons and also is found in Gabon, Zaire, the Sudan, and southern Zambia. The vines, which grow up to 15 feet long, bear tight clusters of 50 to 100 berries, which yield monellin, a protein that is about 3,000 times as sweet as sucrose. Like thaumatin, however, monellin loses its sweetness upon heating or even when stored for a day at 68°F.
Miracle fruit (miraculous berry)
Miracle fruit was known to the West as long ago as 1852, but scientific studies didn’t begin until the late 1960s, when researchers identified its sweet compound, a glycoprotein that they named miraculin. Ingesting miracle fruit causes sour foods to taste sweet and vice versa for about an hour. There is no record of the use of miracle fruit outside of its native habitat.
In 1977, the FDA denied a petition to register miracle fruit on the GRAS list because of insufficient history of consumption in the United States.
The herbal sweeteners described here are those that we know the most about, but there are many other sources of sweet taste that Western scientists haven’t yet explored. While it may take some time to develop these “new” sweeteners on a large scale, they may eventually provide us with the ideal alternative sweetener. Until then, you may wish to try tasting products containing stevioside, the most readily available of the sweeteners (ask for it at your local health-food store) and compare it to products containing processed sugar. See whether your sweet tooth knows the difference.
Art Tucker is a research professor at Delaware State University in Dover. He is an authority on essential oils and the taxonomy of herbs and is a member of the Herbs for Health Editorial Advisory Board.
Bea Ferrigno is a freelance writer and editor in Fort Collins, Colorado.
David Richard’s S. rebaudiana: Nature’s Sweet Secret (Blue Heron Press, 1996) gives an overview of this sweetener’s history, botany, pharmacology, and current usage, including recipes.
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Witty, M., and J. D. Higginbotham, eds. Thaumatin. Boca Raton, Florida: CRC Press, 1994.