Stevia Side Effects - Should You Be Worried?

The herbal sweetener stevia has been used for over 400 years, without any reported ill effects, around the world from South America, where it is native, to Japan.  Indeed in Japan it outsells commercial sweeteners like Sweet'N Low.  Coming to prominent Western attention during the first wave of the 90s low carb diet popularity - because it provides a sweet taste with no carbs or calories - stevia is still relatively unknown, compared to chemical artificial sweeteners like sorbitol and aspartame.  So why had the US Food and Drug Administration branded the naturally sweet herb stevia as an 'unsafe food additive' until 2008?  Particularly given that the FDA already approved stevia as a 'food supplement', for which it must pass stringent tests for potential ill effects.

The main criticisms of stevia revolve around 3 main areas.

The first is that the active ingredient, stevioside, can affect carbohydrate metabolism in mammals, in ways that are not fully understood - before the slimmers seize upon it, more research is needed.  It has been shown to lower blood pressure, which might have implications for users with diabetes or pre-existing low blood pressure.

Secondly, another substance found in stevia called steviol can be converted - in the lab - to a mutagenic compound, ie one that can cause mutations to cell DNA.  This is a potentially serious finding, because anything messing with the genetics of a cell could theoretically cause cancerous growth.  Obviously this is a major 'red flag' of warning and sounds extremely threatening, however chemically it's not that unusual a situation and there is no evidence of this conversion actually occuring in human cells, and the methodology of this particular study has been extensively criticized.

A third experimental result from Europe indicated negative side effects on the reproductive systems of rats and hamsters.  These experiments involved mega-doses of stevia, and again no similar effects have ever been proven or tested in humans.

All these tests prove is that when you isolate specific chemicals from natural substances and feed them to small animals in staggering concentrations, bad things happen.  Given that stevia is around 300x sweeter than sugar, the tiniest amounts are needed, not huge doses, and these results could probably be replicated using countless different common and more familiar foodstuffs. However, many campaigners suspect that the vested interests of the major sugar corporates were behind the length of time it took for this natural herb to finally receive the FDA's 'Generally Recognised as Safe' status.  

Unfortunately, to thoroughly test and replicate the kind of research that is required to debunk these 'findings' of side effects would take the kind of resources that small importers of unusual natural products simply don't have.  

Legislation in Europe is also currently throttling 'novel' foods,  which have been in use around the world for centuries yet not subjected to the testing required for something apparently new in that market - but in 2010 the European Food Safety Authority confirmed that steviol gycosides were safe fo ruse in food and beverages.

It would appear then that side effects from stevia are no more likely than any other natural food, this natural herbal sweetener can be enjoyed by most consumers without any problems.