Stevia is a natural sweetener formulated from the green stevia shrub native to South America and western North America. It has 200 to 300 times the sweetness of sugar, but has no calories. It has been used for centuries as a sweetener in its native Paraguay. While the FDA has held up its wide-scale use in the United States, it has declared certain highly refined stevia preparations as "generally recognized as safe." Some people may develop side effects, including headaches, from stevia.
Stevia has been widely used in Paraguay and Brazil for centuries to sweeten herbal and medicinal teas. It has been used as an artificial sweetener in Japan since the early 1970s, accounting for 40 percent of the Japanese sweetener market. It is also used in other countries including Russia, Australia, Mexico, Malaysia, China, Korea, Taiwan, Israel, Uruguay, Peru and Columbia. In 1991, the FDA banned stevia in the United States because of several early in-vitro studies and several studies that found toxic effects in rats exposed to high levels of stevia. The FDA modified their decision in 1995, allowing the sale of stevia as a supplement, but not as a food additive. In 2008, the FDA allowed certain refined preparations of stevia to be included as an additive and sold as a sweetener, according to Food Insight. It is used in several sodas as a sweetener and sold as a sweetener under various names, including Truvia and Pure Via.
Refined stevia extract and various stevia leaf products are available in health food stores and many supermarkets, typically shelved near sweeteners. A study published in November 2007 in the "Journal of Agricultural and Food Chemistry" indicates that stevia may be useful as a potential source of natural antioxidants that protect against tumors and DNA damage. However, stevia is primarily used as a sweetener. Advocates point out that stevia provides a low-calorie alternative to sugar. It does not trigger an insulin response, may lower blood sugar and it is generally safe for diabetics to use as a sugar replacement.
The pharmacological, hormonal and metabolic effects of stevia on humans and animals have been evaluated in numerous studies, reports Food Insight. The World Health Organization concluded in 2006 and 2008 that stevia is safe. The FDA still harbors concerns that pure leaf stevia products may have adverse effects on blood sugar control, kidneys, cardiovascular functioning and reproductive system.
Headaches and Other Side Effects
Some people complain that stevia causes dizziness or headaches. People who are allergic to plants such as ragweed, marigold and daisies may have adverse reactions to stevia that include headaches. Stevia also may interact with lithium. Stevia may heighten the effect of diabetes medication, causing blood sugar to drop too low, which could contribute to headaches and dizziness, as well as other adverse reactions. Effects on fetal development have not been established and as such, expectant mothers should avoid using stevia.