Just WHAT is Stevia?

Stevia (STEE-vee-uh) is a South American shrub whose leaves have been used for centuries by native peoples in Paraguay and Brazil to sweeten their yerba mate and other stimulant beverages.  Stevioside, the main ingredient in stevia (the two terms are often used interchangeably), is virtually calorie-free and hundreds of times sweeter than table sugar.

I am sure you have seen the television commercials for it, you know the one with the green leafs and proclaiming it is "all natural."  So,m why don't you  see stevia on supermarket shelves next to the Sweet’N Low or Equal?  The is a GRAS List that is the jusdiction of the Food and Drug Adminstration.  The GRAS List is a list of food additives that are 'GENERALLY RECOGNIZED AS SAFE' (GRAS).  This means the food is considered safe by experts, and so is exempted from the usual Federal Food, Drug, and Cosmetic Act (FFDCA) food additive tolerance requirements,  The substance must be shown to be "generally recognized" as safe under the conditions of its intended use.

The hasn’t approved stevia  because they do not have enough data to conclude that the use of stevia would be safe in food.  The U.S. isn’t alone. Canada doesn’t allow food companies to add stevia to their products. Nor does the European Union.  In 1999 the scientific panel that reviews the safety of food ingredients for the EU concluded that stevioside is “not acceptable” as a sweetener because of unresolved concerns about its toxicity. In 1998, a United Nations expert panel came to essentially the same conclusion.  Further verdicts about the use of stevia remain out or are inconclusive.

Now you ask, "What about the manufacturer's claim that it is all natural?"  Well, if it WERE all natural, you would be buying green leafs as stevia.  But you don't.  It comes in a white powder that you can buy it in health food stores as a dietary supplement. The FDA has little control over supplements as there are no laws governing supplements at that time.  

The herb of which stevia is dervived has been consumed without apparent harm in different parts of the world for many years, they argue. No reports of any adverse reactions have surfaced after 30 years of use in Japan, for instance.  But the Japanese don’t consume large amounts of stevia.

In the U.S., we like to go to extremes.  So a significant number of people here might consume much greater amounts. Stevioside seems to affect the male reproductive organ system,” European scientists concluded last year. When male rats were fed high doses of stevioside for 22 months, sperm production was reduced, the weight of seminal vesicles (which produce seminal fluid) declined, and there was an increase in cell proliferation in their testicles, which could cause infertility or other problems.1 And when female hamsters were fed large amounts of a derivative of stevioside called steviol, they had fewer and smaller offspring.2 Would small amounts of stevia also cause reproductive problems?  No one knows.  Do you want to risk it?  Well I am not.

In the laboratory, steviol can be converted into a mutagenic compound, which may promote cancer by causing mutations in the cells’ genetic material (DNA). Hey, the same thing was said about Sweet-N-Low and Equal and Nutra-Sweet. 

Very large amounts of stevioside can interfere with the absorption of carbohydrates in animals and disrupt the conversion of food into energy within cells. The bottom line: If you use stevia sparingly (once or twice a day in a cup of tea, for example), it isn’t a great threat to you. But if stevia were marketed widely and used in diet sodas, it would be consumed by millions of people. And that might pose a public health threat.

All of this means is that some issues still persists with stevia that must be clarified for the FDA before any approval can be considered.

sources:
J. Food Hyg. Soc. Japan 26: 169, 1985.

Drug Chem. Toxicol. 21: 207, 1998.