

Kaa he-he, sweet herb of Paraguay, caa-ehe, honey leaf
Stevia rebaudiana is an herb native to Brazil and Paraguay. The raw leaves as well as the purified extracts, such as stevioside and its aglycone steviol, have been used as sweeteners and promoted as a sugar substitute for diabetics (2). Stevia extract is said to be 2-300 times sweeter than table sugar (1). The FDA has approved stevia as Generally Recognized as Safe (GRAS) (8).
In vitro and animal studies suggest that stevia may have antitumor (5) and anti-inflammatory properties (6).
Stevia was also shown effective in lowering hypertension and hyperglycemia (3) (13). In a placebo-controlled trial in patients with hypertension, stevioside usage improved quality of life when compared to placebo (4). Well designed trials are warranted.
Stevia may have additive effects with other antihypertensive and antidiabetic medications. Gastrointestinal and neurological side effects as well as mutagenic activity have been reported (3) (4) (7).
The mechanisms underlying the antihypertensive effect of stevioside are still unclear, although it is believed to act as a calcium channel antagonist, similar to the drug verapamil (9). It may also have antitumor properties, as evidenced by its inhibition of the tumor-promoting 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse skin (5). In vitro studies have shown that stevioside suppresses the production of inflammatory mediators (6). Stevia products have been shown to inhibit hepatic gluconeogenesis (10) and increase insulin sensitivity in animal studies (11).
Stevioside is hydrolyzed to steviol before being absorbed in the intestines. Steviol is metabolized by the liver microsomes (10).
There have been some studies showing that steviol at high dosages may possess weak mutagenic activity (7).
Pregnant women should not consume this herb.
Case Report: Four patients in a study experienced abdominal fullness, myalgia, nausea, and asthenia following consumption of 500 mg stevioside powder. Their symptoms disappeared after following one week of treatment. (4)
Bottom Line: Stevia can be used as a sweetener.
Stevia is a sweet herb that is used as a sweetener. The FDA has approved a purified ingredient from Stevia as a food additive. Some studies have shown that stevia helps to lower blood pressure in humans. Other animal and laboratory studies suggest stevia products can suppress inflammation mediators in the body and can help to regulate blood sugar level. However, these effects have not been studied in humans.
There have been some studies showing that steviol at high dosages may have weak mutagenic activity.