My latest herb discovery is stevia rebaudiana—aka Sugar Leaf—a member of the chrysanthemum family. On a recent tour of the Chicago Botanic Gardens, the docent encouraged us to taste a small bit of leaf from the stevia plant. She told us stevia is considered to be 200-300 times sweeter than sugar by volume. I concur; a small amount of leaf was very sweet. I began to think about using stevia leaves as an herbal, calorie- and carb-free, sweetener for tea, which is how, in the process of buying the stevia plant, I also bought several herbs to make tea; or more correctly an infusion, as tea is made from the Camellia sinensis plant. Basically an infusion consists of the leaves and maybe some flowers from an herb plant put into boiling water and allowed to steep until the beverage reaches the desired strength. (Some recipes call for fresh leaves and flowers; others specify dried. I have not yet achieved the perfect cuppa tea recipe.)
But I digress. Back to the discussion of eliminating sugar: According to Livestrong.com, “Stevia cannot be absorbed by the intestines and has no calories, and it has a glycemic index of zero. Foods with a high glycemic index cause your blood sugar to rise. Sugar has a glycemic index of approximately 58, while honey ranges from 30 to 58 depending on its composition.” Oregon Health and Science University explains: “Eating foods with a lower glycemic index can help prevent or treat diabetes, so if you are concerned about blood glucose levels, stevia is the best sweetener and honey may be slightly better than sugar.” Honey contains vitamins and minerals, which makes it more nutritious than table sugar. Stevia is nonnutritive, which means it contains no vitamins or minerals.
Pure stevia has been used as a sweetener in its native Paraguay for centuries, but discovery of its sweetness is attributed to Dr. Moises S. Bertoni, an Italian/Swiss botanist, in 1901. The sweetness of the Stevia plant comes from constituents of its leaves called steviol glycosides. There are at least ten known steviol glycosides of which stevioside and Rebaudiaside A (Reb A) are most prevalent. Japan began to commercially produce a sweetener in 1971 comprised of steviol glycosides. There was a big anti-stevia campaign at one time (rumored to be anonymously started by agri-business) and the FDA banned its use as a sweetener for about twenty years. Then in 1991 the FDA designated the highly refined product as “Generally recognized as safe” (GRAS) for use for human consumption. Shortly after that Coca Cola/Cargill came out with Truvia and Pepsi/Whole Earth Sweetener Company brought out their new PureVia brand of sweetener. Positive safety opinions from health organizations from around the world are opening up new markets for the use of steviol glycosides in food products.
Stevia rebaudiana is an annual in areas with freezing temperatures but can be grown indoors on a sunny windowsill. It is recommended to start with a plant or cuttings rather than with seeds to get the best quality plant. After the last frost, once temperatures are in the sixties, the plant can go into well-draining, compost-rich soil in a sunny location or a soilless mix if in a pot. If necessary, fertilize lightly with a low nitrogen fertilizer. Water enough to keep the plant from wilting but avoid overwatering as it reduces stevoside content. Plants mature in around three months and reach 2.5 feet tall and a spread of 2 feet. Stevia can be grown as a companion plant with flowers or vegetables and purportedly repels grasshoppers and aphids. Harvesting the stevia leaves late in the season, just before flowering, will provide leaves with the greatest sweetness. (Obviously the sweetness of stevia leaves is not as concentrated as commercial sweeteners.)
I have only used stevia in tea but some people recommend the leaves in a salad. I like the sweetness and the slightly licorice aftertaste of the leaf, I like the no calories, no sugar, and fresh from the garden aspects of stevia. But I will not be pursuing recipes with this plant. I tried stevia on four occasions by itself and in tea and developed intense itching and hives! Like all herbal supplements, moderate use is recommended, and be aware that you may be ingesting stevia in commercial products. A few warnings regarding stevia: Pregnant and breast-feeding women should avoid the use of stevia until further testing is done. Anyone allergic to ragweed, daisies, marigolds, or anything from the chrysanthemum family may have a reaction. Those wanting to use stevia medicinally to lower their blood pressure or blood sugar should consult their doctor.