Sunday, February 14, 2010

Stevia... Is it safe?

I'd like to start by saying that I am not a nutritionist. I'm simply a Personal Trainer with a great interest in Nutrition and the health of myself and my clients.

It all started when I went to my local healthy grocery store, Sprouts. I'm a lover of drinks, non-alcoholic of course, and one of my favorite isles to check out is the one with all the alternative soda options. They have sodas sweetened with organic cane sugar or "evaporated cane juice" (pretty much the same thing). They also have some sodas sweetened with one of my favorite low-glycemic sweeteners, Agave nectar. As I went down the isle, I saw a new kind of sweetener, Stevia (although the drink it was in is called Zevia). "What the heck is Stevia?" I wondered to myself. Being so against artificial sweeteners, I read the back, only to find out it comes from a plant source, meaning it wasn't chemically created. That's all fine and good, but there are plenty of plant sources out there you don't want to ingest. To name one off the top of my head, Tabacco. However, in the name of science, I decided to do a little experiment with myself.

I started the month of February by taking sugar out of my diet, and replacing it with Agave Nectar, and Stevia. I bought two 6-packs of Zevia sodas (one orange, one lime) to test the taste, and the effect on my body. From my own experience, I have two things to complain about Zevia. Number one, the taste. Gross. It's like aspartame in a way. Super sweet, weird aftertaste. Number two, how my body responded to the soda. Not only did I ALWAYS feel somewhat queasy after drinking the Zevia, I also got a rather uncomfortable response from my intestines. For that reason alone, I say NO to the Stevia. Honestly, I actually prefer the taste and feel of the sparkling water with a little lemon juice.

On to another personal theory of why Stevia may not be good for you. Going with the concept of moderation in all things, just as massive amounts of sugar do bad things to you, massive amounts of a small plant located in South America, may not be as "natural" as you'd think. How often have you stumbled upon a Stevia plant in your lifetime? Sure, it's POSSIBLE the Native American's used it in one of their drinks (See Stevia's Website). How often did they consume that drink, though? And how long were their life spans? Just because the Native Americans may have consumed Stevia does not mean it's necessarily GOOD for you. They also smoked Peyote and used dung as camp fuel. I wouldn't say they were the models of healthy living.

Aside from the fact that it doesn't make me feel good, and from my own personal theories on the matter, there have been a few recent studies that have come out about Stevia. These studies say that Stevia may in fact be good for you.

"Stevia Effects: A New StudyThis latest study on stevia effects was published in the journal of Food and Chemical Toxicology. It showed that Rebaudioside A, derived from the stevia leaf, was non-toxic and showed no evidence of genotoxicity at doses of 750 mg. per kg. of body weight in mice and 2000 mg. per kg. of body weight in rats. The researchers emphasize these results are consistent with previous stevia studies and that stevia is safe and non-genotoxic. The conclusions reached from this study on stevia effects should be welcome news to those eager for a safe, natural sugar alternative.

Stevia Effects: Are There Benefits?Some stevia studies have shown that this natural sweetener may have additional health benefits. In rats, it appears to increase insulin sensitivity. If this holds true in human, it could be beneficial for those with diabetes and metabolic syndrome. Some stevia studies have also shown that it helps to lower blood pressure and could be useful for those with hypertension. "

The only negative study on Stevia I found, was cited in Wikipedia:

"A 1985 study reported that steviol, a breakdown product from stevioside and rebaudioside (two of the sweet steviol glycosides in the stevia leaf), is a mutagen in the presence of a liver extract of pre-treated rats[33] — but this finding was criticized on procedural grounds that the data were mishandled in such a way that even distilled water would appear mutagenic.[34] Over the following years bioassay, cell culture, and animal studies have shown mixed results in terms of toxicology and adverse effects of stevia constituents, but in general, they have not been found to be harmful. While reports emerged that found steviol and stevioside to be weak mutagens,[35][36] the bulk of studies show an absence of harmful effects.[37][38] In a 2008 review, 14 of 16 studies cited showed no genotoxic activity for stevioside, 11 of 15 studies showed genotoxic activity for steviol, and no studies showed genotoxicity for Rebaudioside A. Nevertheless, even if a chemical can cause DNA damage in the controlled conditions of a bioassay (e.g., in bacteria, in mammalian cell cultures) it is a fundamentally different question whether it causes cancer in intact organisms (e.g., rodents, humans) or is teratogenic (i.e., causes birth defects). No evidence for stevia constituents causing cancer or birth defects has been found.[37][38]"

And, as you can see, it may not be a very reliable study.

So what do I personally recommend? I say, if you want a little Stevia, go for it. I feel like it hasn't really been used long enough for anyone to know for sure the effects, however the studies seem to point to it being a relatively safe thing to ingest. I do caution, however, that you don't overuse Stevia. Use it in moderation. Limit yourself to one Stevia sweetened beverage a day. Personally, because of my own experience, I am going to stick with using Agave nectar as my sweetener of choice. I'll explain in my next article why.