Stevia: A "natural" sweetener?

What is Stevia?

Stevia, also known as sweet leaf or sugar leaf, is a group of plants and herbs that is native to subtropical and tropical areas in North America and South America. Stevia is said to be about 300 times sweetener than sugar, which makes it a low-Calorie, low-carbohydrate choice to be harvested into a sweetener, or sugar substitute.

In some countries, such as Japan, Stevia has been used as a sweetener for decades. Countries such as Canada and the U.S., however, were much more hesitant to approve the sweetener, forcing manufacturers to label and sell it as a dietary supplement instead. In 2008, the FDA did approve the sweetener to be used as a food additive, which means you may be seeing it in diet sodas across the U.S. Big players like Coke and Pepsi have been dying to market and sell the stuff, and some suggest the changes in regulations have been more to do with industry pressure than a legitimate concern for safety.

What the science says:

The science for stevia gets a bit confusing because there are so many forms and types of extracts of the stevia leaf. Some extracts have been found to be harmful, others have not. Some studies have shown that Stevia may have positive effects on obesity, high blood pressure and blood glucose control; others have not.

In 2006, the World Health Organization (WHO) performed a thorough evaluation of recent experimental studies of stevioside and steviols available at the time and concluded that "stevioside and rebaudioside A are not genotoxic in vitro or in vivo and that the genotoxicity of steviol and some of its oxidative derivatives in vitro is not expressed in vivo." The report also found no evidence of carcinogenic activity and that "stevioside has shown some evidence of pharmacological effects in patients with hypertension or with type-2 diabetes" but concluded that further study was required to determine if these affects could be seen at a safe dosage. "The Committee therefore decided to allocate a temporary acceptable daily intake (ADI), pending submission of further data on the pharmacological effects of steviol glycosides in humans, of 0?2 milligrams per kg of bodyweight.

My opinion?

I say this time and time again - just because something is "natural" or comes from a leaf does not make it safe. Many powerful herbs and drugs come from plants, and anytime we're putting anything new into our bodies, caution is warranted. Secondly, maybe it has been used for centuries in the bushes of South America, but that's different than going out and buying it in a bottle like we would today. When you purchase stevia from a store, it has been chemically processed to produce one singular extract from the leaf, and what you are getting resembles more of an artificial sweetener than a "natural" leaf. Companies also have to alter the product to try and rid it of a naturally occurring bitterness. Anytime processing is involved, you alter the naturally integrity of the plant, which may or may not affect its properties.

At the end of the day, no sweetener is good for you in large amounts, no matter how natural. The best thing to do is limit your intake of sweetened foods and beverages altogether. Period. For me, if I need a little sweetness, I'm still reaching for the real thing.

Sources: WHO Report, Center for Science in the Public Interest