Dr. Oz does cite one of the few studies that were ever done that support that position. However, stevia is a noncaloric herb, native to Paraguay, that has been used as a sweetener for over 1500 years in South America.  I would call that a MAJOR clue that it is safe.

While Japanese manufacturers have used stevia since the early 1970s to sweeten pickles and other foods, the FDA has turned down three industry requests to use stevia in foods in the U.S. Stevia has been the subject of searches and seizures, trade complaints, and embargoes on importation. Supporters of stevia assert that FDA actions regarding stevia amount to a restraint to trade designed to benefit the artificial sweetener industry.

The FDA’s treatment of petitions to approve stevia is quite interesting in light of their historically generous attitude toward synthetic chemical sweeteners. The general tone of the FDA is that stevia is an unsafe substance until proven otherwise. Artificial sweeteners, as you have seen, are in contrast generally viewed as benign chemical compounds that are considered safe until someone shows them data to the contrary. Stevia is guilty until proven innocent; artificial sweeteners are innocent until proven guilty.

I am seriously disappointed in Dr. Oz's approach in accepting the FDA review of stevia, but even MORE disappointed in his ignorance in believing that aspartame is safe and actually advising people to use this dangerous substance. It is obvious he has never examined the evidence. Pity.

I carefully reviewed this topic for several years and wrote Sweet Deception that summarizes my findings on sweeteners. I encourage you to read a copy.