Stevia herb extract has been used as a natural herbal sweetener for centuries in many parts of the world. Stevia rebaudiana is a plant that belongs to the sunflower family. It is found in abundance in the subtropical and tropical South American and Central American regions. The plant has been used for centuries in countries like Brazil and Paraguay to sweeten the local 'yerba mate' tea, and also as a herbal medicine.
The leaves of this plant are sweeter than the ordinary table sugar. They can be used to prepare teas or various types of foods, or they can even be eaten raw. Steviol glycosides, the active compounds present in stevia leaves, have 250-300 times the sweetness of sugar.
The use of this herb as a natural sweetener was spearheaded by Japan after a 1960s ban on all artificial sweeteners such as saccharine and aspartame. Its use as a sweetener became so popular that many other countries followed in its lead. In 1991 the FDA had refused to approve use of natural stevia due to pressure from manufacturers of artificial sweeteners. But in 2008, the FDA approved the use of rebaudioside compounds that were derived from the stevia plant by Coca-Cola (marketed by Cargill) and PepsiCo.
These days, stevia extracts and derivatives are produced by several companies, and are marketed under various trade names, for example, Rebiana, Truvia, PureVia, etc. According to the FDA, the sweetener Truvia from Coca-Cola and PureVia from PepsiCo (both use rebiana), the extracts from the stevia plant, can be referred to as "generally recognized as safe." Today, stevia is used as a commercial sweetening agent for many mass-produced and marketed food products, such as low calorie foods, diet sodas, bakery items, etc.
Side Effects of Stevia
In the United States, stevia has not been accorded the status of a food additive or sweetener, but as that of a dietary supplement. Some scientific reports have indicated that its extract stevioside may cause health problems to the consumer. The WHO's Joint Experts Committee on Food Additives and The European Food Safety Authority have approved an acceptable daily intake of steviol glycoside of up to 4 milligrams per kilogram of body weight. Excessive consumption can lead to certain side effects. Although no serious side effects have been reported, probable medical problems associated with its consumption have been listed below for your information.
Headaches and nausea are some of the most common problems (due to an allergic reaction) one can experience after consuming it. One may experience dizziness, skin rash, hives, labored breathing, wheezing, fatigue, or difficulty in swallowing food. Although rare, stevia can cause a severe allergic reaction called anaphylaxis. Those who are allergic to chrysanthemums, marigolds, ragweed, or daisies may experience such side effects.
Damage to Metabolism
Animal studies conducted by the Center for Science in the Public Interest have shown that a large dose of stevioside may cause interference with the absorption of carbohydrates in the body, resulting in a hampered conversion of food into energy.
In 2006, a group of European scientists experimented on male rats and female hamsters by feeding them doses of stevioside and its derivative steviol respectively, to draw conclusions about stevia's side effects on the male and female reproductive organs. The rats sperm production and the weight of the seminal vesicles drastically reduced, whereas the hamsters delivered (pups) babies that were small in size and weak. More studies are required to prove that use of stevioside could result in infertility or other reproductive problems.
Digestive / Respiratory Problems
Some products contain silica as an ingredient as it improves the flow of the powdery product. They can cause irritation of the digestive and respiratory tracts. Regular use of stevia can lead to gas, bloating, muscle pain, numbness, nausea, etc.
Although many tests have been conducted to check for the role of this sweetener in causing cancer, and scientists have not been able to prove that it is carcinogenic, it is still quite disputed. Labels of various stevia products show 'erythritol' as an ingredient. Although erythritol is a naturally occurring sugar (present in fruits), manufacturers of stevia don't actually use it in its natural form (it would be expensive). They use genetically engineered corn and a complex fermentation process to get chemically pure erythritol. Some contain dextrose, a sweetener that is also derived from genetically engineered corn. Some contain agave inulin, a highly processed fiber derivative from the blue agave plant. Various chemicals used during the refining processes and use of genetically engineered corn can cause cancer. Moreover, in a laboratory controlled experiment, it was found that stevioside derivative steviol can be converted into a genetically mutated compound. Mutations of cells leads to cancer.
Interaction with Medicines
Stevia may cause low blood pressure. So, those who are taking blood pressure medications should consult their doctor before opting for stevia. The combination can lead to hypotension (abnormally low blood pressure). Similarly, those who are taking insulin or oral medication for diabetes need to be monitored closely, as the combination of diabetes medication and stevia can cause hypoglycemia, low blood sugar levels. Those taking lithium should also consult the doctor before taking stevia.
Stevia provides the taste of a sweetener without adding calories to the diet of a person. Manufacturers claim that it does not lead to fluctuations in blood sugar levels in diabetics, and that it has also been helpful in lowering elevated blood pressure. Its anti-bacterial properties suppress the growth of bacteria. It is widely used in toothpastes and mouthwashes. As it contains no calories, its products are highly recommended in weight loss and weight management programs. Its healing properties can help in curing some common skin inflammations, like, acne, dermatitis, and eczema.
Most side effects of stevia require further testing, especially on humans. For all those who believe in its benefits, it is preferable to consult a doctor before consuming it, to avoid any of the above mentioned health complications.