Is Stevia safe for life?

Stevia is perhaps unique among food ingredients because it's most valued for what it doesn't do. It doesn't add calories. Unlike other sugar substitutes, stevia is derived from a plant.Stevia has no calories, and it is 200 times sweeter than sugar in the same concentration. Other studies suggest stevia might have extra health benefits.

"Available research is promising for the use of stevia in hypertension," said Catherine Ulbricht, senior pharmacist at Massachusetts General Hospital in Boston and co-founder of Natural Standard Research Collaboration, which reviews evidence on herbs and supplements. Ulbricht said Natural Standard gave stevia a "grade B for efficacy" in lowering blood pressure.

A no-calorie source of sweetness is an obvious diet solution in theory. But a few studies show that replacing sugar with artificial or low-calorie sweeteners may not ultimately lead to weight loss in real life.Yet there is also evidence that stevia does nothing to change eating habits or hurt metabolism in the short term. A 2010 study in the journal Appetite tested several artificial sweeteners against sugar and each other in 19 lean people and 12 obese people.

The study found people did not overeat after consuming a meal made with stevia instead of sugar. Their blood sugar was lower after a meal made with stevia than after eating a meal with sugar, and eating food with stevia resulted in lower insulin levels than eating either sucrose or aspartame.The question of whether stevia is safe to consume largely depends on what someone means by "stevia." The U.S. Food and Drug Administration have not approved stevia leaves or "crude stevia extracts" for use as food additives. Studies on stevia in those forms raise concerns about the control of blood sugar and effects on the reproductive, cardiovascular, and renal systems, the FDA warns.

However, the FDA has allowed companies to use an isolated chemical from stevia as food additive, calling the chemical "generally recognized as safe." Now, products such as Truvia and others have the legal go-ahead to use Rebaudioside A, which is also found in stevia, in their no-calorie sweeteners.But there are some health concerns surrounding the stevia plant. Stevia may cause low blood pressure, which would be of concern to some taking blood pressure medications.

"Caution is advised when using medications that May also lower blood sugar. People taking insulin or drugs for diabetes by mouth should be monitored closely by a qualified health care professional, including a pharmacist," Ulbricht said.

Stevia may also interact with anti-fungal, anti-inflammatories, anti-microbial, anti-cancer drugs, anti-viral, appetite suppressants, calcium channel blockers, cholesterol-lowering drugs, drugs that increase urination, fertility agents and other medications, Ulbricht said. People should talk with their doctor before deciding to take stevia in large amounts, she said.