There's a lot of buzz in the food and nutrition world about a couple of new natural zero-calorie sweeteners, Truvia (from Coca-Cola) and PureVia (from PepsiCo). These two sweeteners contain stevia, an extract from a plant native to South America, and the FDA recently approved the use of these sweeteners as food additives that have been declared GRAS (generally recognized as safe). Some controversy swirls around stevia and stevia-containing sweeteners for several reasons. First, previous studies in animals suggested that high doses could result in male infertility and fewer and smaller offspring for females while other studies suggested potential cancer-causing activity. Critics of this approval also point out the loopholes in the GRAS identification since the testing on safety can be carried out by manufacturers themselves, which creates an obvious potential bias, and the companies can actually self-declare the safety of the additive without actually notifying the FDA or consumers. Therefore, the FDA does not need to review or approve this GRAS declaration of the scientists conducting the studies, and the only way for the FDA to reverse the GRAS classification is through litigation where it would have to prove that the additive is actually unsafe for human consumption. While stevia has been used in foods in countries such as Japan for decades, it has been banned in the European Union, Singapore, and Hong Kong.
What about the other side of the story? Well, the fact remains that stevia-extracts have been used in Japan and Brazil for many years with no reported harm to humans. Other studies have refuted previous trials regarding the physiological effects of stevia. Recent safety studies evaluated the effect of the equivalent of a 150 lb. person consuming 1,000-2,000 daily servings of stevia-sweetened beverages and findings indicated no harmful effects on general health, male or female fertility, and growth or development of adults or their young. Results are mixed on whether or not stevia-containing products may actually have positive effects on health, including blood pressure and blood sugar control in people with type 2 diabetes. In 2006, the World Health Organization (WHO) reported that stevia-extracts were not genotoxic (damaging to cell's genetic material) or cancer-causing based on their own research findings.
Many people are eager to taste the new naturally-sweetened beverages from Coca Cola and Pepsi as these products will likely be rolled out very soon in the U.S. What about you? I must admit that as a foodie, I'm very curious! I've actually tried stevia as a sweetener a long while back although I wasn't a big fan back then. Maybe these new formulations will provide a better taste? After doing my own investigation, I say that moderation is key here as I would with any alternative sweeteners. A possible guide on consumption could come from Australia and New Zealand's acceptable daily intake recommendations of about 4 mg/kg of body weight. For a 150 lb person, this could be the equivalent of about 1.5 cans of a stevia-sweetened beverage daily (and this includes a 100-fold safety cushion). To be honest though, you're probably better off consuming water, low-fat milk, 100% fruit juice or green tea for fluids or other nutrients, antioxidants, or phytochemicals rather than relying on these stevia-sweetened beverages from a nutrition perspective.