Elevated blood pressure is a major risk factor for many serious diseases. This includes heart disease, stroke and kidney failure. Studies have shown that taking stevioside (one of the sweet compounds in stevia) as a supplement can reduce blood pressure.
One of these studies was a randomized, double-blind, placebo-controlled trial in 174 Chinese patients (1). In this study, patients took either 500 mg of stevioside or placebo (dummy pill), 3 times per day. These were the results after two years in the group taking stevioside:
- Systolic blood pressure: went from 150 to 140 mmHg.
- Diastolic blood pressure: went from 95 down to 89 mmHg.
In this study, the stevioside group also had a lower risk of Left Ventricular Hypertrophy, an enlarging of the heart that can be caused by elevated blood pressure. The stevioside group also had improved quality of life.
The mechanism is not well understood, but some researchers have suggested that stevioside may act by blocking calcium ion channels in cell membranes, a mechanism similar to some blood pressure lowering drugs (5).
Stevia May Lower Blood Sugar Levels and Help Fight Diabetes
Type II diabetes is currently one of the biggest health problems in the world. It is characterized by elevated blood sugar in the context of insulin resistance or an inability to produce insulin. Stevia has been studied in diabetic patients with impressive results.
In one of the studies, type 2 diabetic patients took either 1 gram of stevioside with a meal, or 1 gram of maize starch. The group taking stevioside had a reduction in blood sugar by about 18% (6). Another study compared sucrose (regular sugar), aspartame and stevia. It found that stevia lowered both blood sugar and insulin levels after a meal, compared to the other two sweeteners (7).
Other studies in animals and test tubes have shown that stevioside may increase production of insulin, as well as make the cells more sensitive to its effects (8, 9). Insulin is the hormone that drives blood sugar into cells, so this appears to be the mechanism behind the blood sugar lowering effects.
Bottom line: Stevioside appears to improve function of the hormone insulin, helping to lower blood sugar levels. This may be useful for people with type 2 diabetes.
One animal study found that stevioside decreased oxidized LDL cholesterol, indicating that it may help prevent heart disease (10). Stevia has also been shown to have anti-inflammatory, anti-cancer, diuretic and immunomodulatory effects (11).Bottom line: The active compounds in stevia have led to numerous health benefits in animal studies, including reduced oxidized LDL cholesterol.