Stevia

        Stevia Rebaudiana

                Family: Compositae

by Darlene S. Widirstky           


picture of herbs

Description:

Stevia Rebaudiana is a sub-tropical plant and prefers a climate where the mean temperature is 75° F. and is always semi-humid. It thrives where it rains approximately 55" each year. S. Rebaudiana is a herbaceous perennial shrub native to the highlands of Paraguay and sections of Argentina and Brazil that are situated along the 25th Degree Line, South Latitude

In the wild, Stevia grows to 2 feet in height while cultivated varieties grow to three feet. A spindly, many-branched plant with an interesting root system. Fine roots spread out on the surface of the soil, while a thicker part of the root grows deep into the soil. The stems are hairy, wand-like and covered with leaves. Leaves are opposite and toothed, fibrous and dark green. Flowers are white, tubular and bisexual. While the plant itself is not aromatic, the leaves are sweet to the taste and dry leaves are sweeter.

Stevia was discovered in 1887 by the South American Natural Scientist, Antonio Bertoni. There are approximately 80 wild species in North America and another 200 species are native to South America. However, only Stevia Rebaudiana (and another species, now extinct) possesses the natural sweetness we look for. Some of the other species, while still very sweet, have a taste reminiscent of a well-known artificial sweetener.

Propagation:

Propagation occurs naturally from scattered seed, root division and stem layering. In its native Paraguay, S. Rebaudiana prefers growing in the coarsely textured, infertile acid sands, or in grasslands with shallow water tables. Stevia is also known as "Honey-Leaf", "Sweet-Leaf" and "Sweet-Herb".

Cultivation:

In our own area (N.Y., L.I., agricultural zone 7), starting Stevia from seed is very difficult. If you´re interested in raising Stevia, try mail-order plugs or rooted cuttings. It requires a great deal of water initially and should be watered very shallowly every 2-3 days. S. Rebaudiana is a tropical annual with approximately 150 species. S. Rebaudiana was introduced to N. America about 1980. Other species such as S. Serrata or florist´s "stevia" (Piqueria trinervia) are native to southernmost California, New Mexico, Arizona and Texas. Even in these subtropical or tropical areas, Stevia is a tender perennial (or hardy annual) and must be potted up and brought indoors for the winter months. Cultivate as you would any tropical plant. It seems to be relatively disease-free. While the plants are outdoors though they do seem to attract slugs. Prune often to keep the plant full otherwise it will start looking like a gawky vine.

Herbal uses:

The Guarani Tribe of Paraguay, the Mestizos and other natives refer to Stevia as Ca-h- and they have used the herb to sweeten their bitter beverages (mate´ for example) since pre-Columbian times.

Culinary: Used primarily as a sweetener in teas and coffee and contains little, if any, calories. In other countries, it is used commercially to sweeten sodas and other beverages for the calorie conscious public. Stevia does not break down when heated, so it can be used in baking or cooking without problems. However, it does not crystallize or caramelize like sugar; so meringues and flans are not in the Stevia cooking list. Stevia products currently on the market include: Stevia leaves - whole leaves. Stevia, Cut and Sifted - the leaves are cut into smaller pieces and sifted to ensure that twigs and extraneous matter are not included.

(To my knowledge these statements have not been evaluated by the FDA. This product is not intended to diagnose, treat, cure, or prevent any disease.)

Stevioside - this is an isolated extract, and is considered purer than the above two products. However, it is also the most highly processed and denatured of the available products. From a nutritional point of view, it is not a good choice. Stevia Liquid Extracts - Processed usually in a water and alcohol base, these extracts may be created from any of the previously mentioned products. Stevia Packets - single serving packets. Stevia Concentrate - liquid concentrates can also be purchased in several forms. The syrupy black liquid is used to enhance the flavor of many foods. You can concoct one yourself from the recipe that follows: Bring 2 cups of distilled water to a boil; lower the heat, and add ounce of dried Stevia leaves. Bring the water back to a boil, and boil for 3 minutes. Turn the heat off and allow to cool. Filter, bottle, and refrigerate.

Medicinal: As a herbal dietary supplement, only. Stevia has been shown to be an exceptional aid in weight management. Other benefits of adding Stevia to your daily diet may include improved digestion and gastrointestinal function soothed upset stomachs, and quicker recovery from minor illness.

Scientific research has been done in other countries that use Stevia on a regular basis. Some indicate that Stevia effectively regulates blood sugar and brings it towards a normal balance. It is sold in South America as an aid to people with diabetes and hypoglycemia. Still more studies have indicated that Stevia tends to lower elevated blood pressure while not affecting normal blood pressure. It is also being investigated as an anti-bacterial substance.

Pharmaceutically, the secret to Stevia´s success is a complex molecule named Stevioside. (glucose + sophorose + steviol = A glycoside [Stevioside])

Stevioside does not affect blood sugar metabolism. Yes, part of this complex molecule is glucose; yet, it contains almost no calories (Stevia extracts are non-caloric). It is recommended and approved as a dietary supplement by the FDA. In addition to Stevioside, eight other sweet-tasting constituents of S. Rebaudiana have been identified to date. The extractive processes were pioneered and patented by the Japanese. They are Rebaudiosides A, B, C, D, and E, Dulcosides A, B; and Steviolbioside. These extracts are very expensive, and are not available in the U.S. The importance of Stevia to the Japanese cannot be overlooked. In the 1960´s, the Japanese government banned certain artificial sweeteners due to health concerns. They started cultivating Stevia plants in hothouses because of the Japanese public´s health concerns towards sucrose and its relationship to obesity, diabetes, and dental care. Today, most of the Stevia products are processed through eleven major manufacturers who have formed the Stevia Association of Japan. Japanese research has been quite extensive, and should not be overlooked when examining the safety issue of Stevia products.

Speaking of Sweet Politics, in May of 1991, the FDA issued an Import Ban on Stevia which effectively blocked the sale of it in the United. States. Some Herbalists believe this was influenced by the artificial sweetener industry. In 1994, the Dietary Supplement Health and Education Act (DSHEA) was passed. DSHEA effectively gives the food industry a chance to inform the public on some of the benefits of herbal products. The FDA is not happy! They felt that lobbying by the food industry was responsible. In September of 1995, the food industry forces the FDA to issue a Revision to the Import Ban on Stevia. The revision stipulates that Stevia (and any products) can be imported, but only as a food supplement. This is due to the fact that the USDA has not affirmed Stevia as GRAS (Generally Regarded As Safe). It cannot be imported, sold, or referred to as a sweetener or as a flavoring agent because The USDA is of the opinion that the available toxicology information is inadequate. In 1997 the FDA came out with a document listing 19 studies that raised "unresolved issues". They insist that if Stevia (or any of its products) is sold as a sweetener or flavoring agent, they will detain or confiscate it, and remove it from the market.

The Herb Research Foundation believes that Stevia´s problem is not due to any toxicology; they believe it´s political. They site a case wherein a complaint was filed by NutraSweet® in the form of a trademark infringement against Sunrider International, a new company in the sweetener industry. They were just introducing their stevia­leaf concentrate Trusweet® as a natural sweetener. The promotional literature depicted a sweetening agent. Sunrider opted to change the product name to Sunectar and changed their labeling from a sweetener to a dietary supplement. Issue resolved - production plant opens. Shortly thereafter a USDA agent appeared at Sunrider´s doorstep, red-tagged all the plants and shut down their plant. They said that they had reason to believe the plants may have been adulterated. This is an example of "sweet politics".

Now back to NutraSweet® and the "Sweetener" industry. Their belief is that if statutory safety requirements for sweeteners (costing millions of dollars) apply to them, then they should apply to all in the industry. Companies that sell natural sweeteners as dietary supplements don´t have to go through all the testing and monitoring requirements the rest of the "Sweetener" industry does. NutraSweet® and other companies that manufacture low or no-calorie sweeteners, say they are being financially hurt by the competition of a relatively safe, naturally sweet product that is unsafe in the eyes of the USDA and the FDA.

Politics are everywhere. Whether Stevia is safe or not has yet to be determined. I find it very interesting that in all the research studies I have run across, none addresses the issue of its use as a contraceptive by the Guarani tribe and other natives of South and Central America, as well as Mexico. What effect does Stevia have to pregnant women, or on an unborn fetus? I can´t answer that. I would rather wait until information is available on this issue before saying Stevia is safe. Maybe this issue is one of those "unresolved issues" the FDA is referring to.

Bibliography upon request


Visit the Horticulture Page here

The author is a Master Gardener and editor of the SCMGS Newsletter (Long Island, N.Y.).