For years I’ve recommended stevia as a no-calorie, non-artificial sweetener to my patients who are trying to abstain from sugar despite a sweet tooth. But lately it’s been getting a lot of flak on the internet.

So is it as dangerous as “they” say?

What Stevia Is

Unlike artificial sweeteners, stevia is an herb that grows in Japan, China, South America, and several other countries around the world. Unlike most other natural sweeteners, it has no effect on blood sugar. This in and of itself is a great health benefit, as most of the big Western diseases are linked to excess sugar consumption.

Additionally, studies show that stevia:

  • Can trigger breast cancer cell death. This study shows that stevia induces apoptosis (self-destruction) in breast cancer cells.
  • Can protect against pancreatic cancer; specifically intake of the polyphenol kaempferol found in stevia was found to reduce the risk by 23% in a cohort of just over 180,000.
  • Improves insulin sensitivity. This study shows that, at least in rats, stevia improves insulin sensitivity and lowers glucose.
  • Contains micronutrients, including potassium, zinc, magnesium, and iron. (This is true of most natural, unprocessed sweeteners.)
  • Has bactericidal properties. Specifically, this study shows the extract can kill a particularly nasty strain of E. coli while leaving gut flora intact.

The Controversy

The arguments against stevia seem to come down to two things, as far as I can tell:

  1. The fact that many stevia extracts are highly processed (they are—the Truvia brand is a product of the Coca-Cola Company, if that tells you anything, and the stevia leaf goes through a 42-step process on its journey to becoming Truvia); and
  2. This study, which suggests that massive doses of stevia can alter fertility in rats.

Other studies have been conducted in an attempt to reproduce the adverse effects of stevia on fertility since. This study, at an enormous body weight dose of 500-800 mg/kg (normal human consumption is about 2 mg) shows no adverse effects on fertility.

The Upshot:

You have to dig deep to find dirt on true, unadulterated stevia, and even then it’s a stretch. On the other hand, eating too much sugar is clearly a bad idea!

My recommendation: buy green leaf stevia (the whole, unprocessed stuff), and use it in moderation. If you can tolerate the aftertaste, it’s a much better choice than sugar. But (fun baking tip): substitute stevia in a recipe that calls for sugar, and you can cut the actual sugar in the recipe in half or more… and you can’t even tell the difference! (Make sure you look up equivalent doses though, because stevia is far sweeter than sugar. If you try a 1:1 substitution, your final product will be inedible.)

For more on sweeteners, check out this article.