Precision Nutrition Blog

The battle of the sweeteners

by Ryan Andrews

Is Splenda is as bad as some folks say it is? Can Aspartame cause cancer? Is the “all natural” sweetener, Stevia, a safe alternative to these “artificial” sweeteners?  In this article, a little research is mixed in with some common sense to arrive at a verdict.

Every day, here at PN HQ we receive a ton of questions about sweeteners in general, artificial sweeteners in particular. This is in part related to the natural relationship between sweeteners and food – nowadays we find sweeteners in almost everything.

However, beyond this simple relationship, many folks have noticed that in our Gourmet Nutrition v1 and Gourmet Nutrition v2 products, we’ve actually discussed the use of sweeteners like Stevia, Splenda, and Aspartame.

Because of this, people want to know whether Splenda is as bad as some folks say it is. They want to know if Aspartame can cause cancer? And they want to know if the “all natural” sweetener, Stevia, is a safe alternative to these “artificial” sweeteners.

So, in this week’s newsletter, we’re going to explore this last question in particular. Is Stevia a safe alternative to Splenda or Equal?

Of course it is: It’s natural

Now, before coming up with a knee jerk response – believing that Stevia MUST be better because it’s natural – take a second to think this through.

Just because Splenda and Equal are laboratory produced while Stevia is a green, harmless looking plant, doesn’t mean that Stevia is great while the other two are pure dietary evil.

After all, hallucinogenic mushrooms, ephedra sinica and poison hemlock all grow in the ground and are completely natural too. And I don’t think too many of you would argue that somehow these organic materials, part of nature’s bounty, are healthy to eat.

So, instead of making up your mind based on the natural vs. artificial debate, let’s actually look into this plant, Stevia, and see what the research has to say.

Meet stevia

Stevia’s real name is stevia rebaudiana (Bertoni) and it is an herb native to Paraguay and Brazil. It can grow to be the same height as your 3 year old nephew (about 3 feet tall). Well, unless that nephew has acromegaly and is abnormally large, like Andre the Giant.

Stevia has actually been used as a sweetener since the year 1600 and has been gaining popularity in recent years. Here’s a little list of stevia facts:

  • Stevia is about 250-300 times sweeter than sugar
  • Stevia is stable to heat, making it safe for cooking
  • Stevosides produced in stevia leaves = sweetness
  • Specifically, the sweetness comes from the isosteviols
  • Stevia is non-caloric
  • Stevia doesn’t promote dental caries, as does sugar

So far, so good.

Once harvested, stevia leaves are processed using water and alcohol. Next, they’re subjected to enzymatic catalysis. Finally, we get stevia extracts.

These extracts are then sold as commercial sweetening agents. Indeed, this process has been used for more than 30 years in Japan and Brazil.

Stevia as a supplement

The USDA was introduced to stevia between 1918 and 1921. And ever since, they continue to greet it with CLOSED arms.

Since stevia grows naturally, it requires no patent to produce it. This has led some to believe that the reason it hasn’t been approved for use as a food additive in the U.S. and Canada is based on financial motivations.

As a result, in the U.S. and Canada, stevia is currently considered a dietary supplement. This shouldn’t be taken lightly. Food manufacturers need to check themselves if they start using it in foods (see here).

Unlike the US and Canada, Japan approved stevia extract as a sweetener around 1970. They have used it in gums, cereals, toothpastes, mouthwash, sodas, etc.

Back in 1941, during World War II, the British seriously studied the possibility of commercially extracting stevia as an alternative to their threatened sugar supplies.

For individuals looking to sweeten tea, coffee, etc – and wanted to avoid artificial compounds – stevia seemed to be the next best option.

Yet they never adopted it…

Are you using?

The term “eight ball” is slang for 1/8 of an ounce or 3.5 grams of methamphetamine or cocaine. Just in case you’re wondering, “eight ball” is not a term used when dealing stevia.

Rather, much of the stevia in North America is measured out in packets, tinctures or tablets.

  • 1 packet usually contains about 85 mg of stevia extract
  • 4 drops of tincture will usually contain about 40 mg of stevia
  • 1 tablet usually has about 50 mg of stevia

Brands tend to vary, so keep that in mind. These numbers will be useful as we get into some of the research.

stevia 2 The battle of the sweeteners

Is It Safe?

When a chemical is being studied for safety, scientists first do what’s called a LD50 test. If you need a quick refresher on pharmacology, LD50 is the dose of a substance required to kill 50% of the tested population.

For obvious reasons, these studies are done in animal populations – and not in humans.

When it comes to stevia, a study back in 1975 reported an LD50 of 15 grams of stevia per kilogram of body weight. For example, if you’re 220lbs, or 100kg, it would take 1500grams to kill you. And if you’re 110lbs, or 50kg, it would take 750g to kill you.

Uh, that’s a lot! Indeed, that’s about 15,000 to 30,000 tablets.

Interestingly, however, another study found that the LD50 min mice was only 2 grams per kilogram. Again, at 220lbs, that’s only 200grams (or 4,000 tablets). And at110lbs, that’s only 100g (or 2,000 tablets).

2g vs. 15g – that’s a pretty wide range of results – something kinda scary when we’re talking about death and all. However, let’s get real here, no healthy person free of some sort of stevia allergy is dying of a stevia overdose.

The table below summarizes the LD50 study results.

Species_____Gender_____LD50 (g/kg body weight)_____Reference
Mouse________M & F _______>15 grams per kilogram_________ Toskulkao 1997
Mouse________M___________>2 grams per kilogram__________ Medon 1995
Rat___________M & F _______>15 grams per kilogram_________ Toskulkao 1995
Hamster______M & F _______>15 grams per kilogram_________ Toskulkao 1995

*To provide a little perspective, the LD50 of caffeine in rats is 192mg/kg. So, for a 60kg human, that would be about 11,500mg or 11.5grams of caffeine. Therefore, relatively speaking, caffeine is much more lethal relative to stevia.

So, in the end, it doesn’t look like any of us will be ODing on stevia anytime soon. However, it’s important to look at the stevia safety data in another way. For this, researchers look at the “no adverse effect” level studied in rats.

The “no-effect” level for stevia is about 794 mg/kg. That means about 7.94 mg/kg/day would be safe for humans. This 7.94 mg/kg/day value is based on a very conservative safety factor of 100X.

And, technically speaking, this is typically called the ADI (or acceptable daily intake). You could probably get away with quite a bit more. However, I’m not sure I’d be the one signing up to test that theory out.

Note: in terms of numbers, for a 110lb adult, that would be about 400mg per day (or about 5 packets) and for a 220lb adult, that would be about 800mg per day (or about 10 packets).

Also note: it’s interesting to consider that in studies with Splenda/sucralose, the ADI is actually 15mg/kg/day. Relative to the ADI of about 8mg/kg/day for stevia, this means double the Splenda/sucralose could be consumed without adverse events.

Steviol and DNA

Interestingly although most of that data we’ve reviewed so far doesn’t raise any red flags for stevia use, there have some negative data published. Indeed, these data suggest excessive use of stevia might lead to health issues, starting with DNA damage.

These data are mixed, however, and have been collected in rats and mice. In total, there are about 10 studies showing that stevia doesn’t cause DNA damage.

However, there are a handful more that show that a natural breakdown product of stevia metabolism – steviol – can damage our DNA.

Not so good. And definitely something to consider.

Reviewing the research

At this point, let’s review the most accessible research looking at stevia.

  1. One study (more recent) gave either 500, 1000, or 2000 mg/kg/day of rebaudioside A (a glycoside found in the stevia leaf) to rats for 90 days.  No toxic effects were noticed.  Nikiforov AI & Eapen AK. A 90-day oral (dietary) toxicity study of rebaudioside A in Sprague-Dawley rats. Int J Toxicol 2008;27:65-80.
  2. Stevia use up to 15 mg/kg/day for 6 weeks appears to be safe in humans. These researchers actually set out to study the effect of stevia on blood pressure. It didn’t have any additional impact over placebo alone.  Ferri LA, et al. Investigation of the antihypertensive effect of oral crude stevioside in patients with mild essential hypertension. Phytother Res 2006;20:732-736.
  3. This study concurs – no impact on blood pressure, but the stevia was well tolerated.  Barriocanal LA, et al. Apparent lack of pharmacological effect of steviol glycosides used as sweeteners in humans. A pilot study of repeated exposures in some normotensive and hypotensive individuals in Type 1 and Type 2 diabetics. Regul Toxicol Pharmacol 2008;Mar 5 Epub.
  4. This study says that stevia does help to control blood pressure. 500 mg of stevioside powder 3 x/day for 2 years significantly lowered blood pressure. No adverse effects were noted.  Hsieh MH, et al. Efficacy and tolerability of oral stevioside in patients with mild essential hypertension: a two-year, randomized, placebo-controlled study. Clin Ther 2003;25;2797-2808.
  5. Similar results from this study.  Chan P, et al. A double-blind placebo-controlled study of the effectiveness and tolerability of oral stevioside in human hypertension. Br J Clin Pharmacol 2000;50:215-220.
  6. This study shows us that stevia may decrease inflammatory mediators. Boonkaewwan C, et al. Anti-inflammatory and immunomodulatory activities of stevioside and its metabolite steviol on THP-1 cells. J Agric Food Chem 2006;54:785-789.
  7. This small study revealed how stevia may be useful for controlling blood sugar in patients with type 2 diabetes. Gregersen S, et al. Antihyperglycemic effects of stevioside in type 2 diabetic subjects. Metabolism 2004;53:73-76.
  8. This review from Phytochemistry states: “Acute and subacute toxicity studies revealed a very low toxicity of Stevia and stevioside. Fertility and teratogenicity studies are discussed as well as the effects on the bio-availability of other nutrients in the diet.  The conclusion is that Stevia and stevioside are safe when used as a sweetener. It is suited for both diabetics, and PKU patients, as well as for obese persons intending to lose weight by avoiding sugar supplements in the diet. No allergic reactions to it seem to exist.” Geuns JM. Stevioside. Phytochemistry 2003;64:913-921.
  9. This study found that stevia doesn’t appear to damage DNA. Suttajit M, et al. Mutagenicity and human chromosomal effect of stevioside, a sweetener from Stevia rebaudiana Bertoni. Environ Health Perspect 1993;101 Suppl 3:53-56.
  10. This study would disagree. The researchers found developing lesions in rats after administering stevia. The authors conclude that stevia may have DNA damaging properties. Nunes AP, et al. Analysis of genotoxic potentiality of stevioside by comet assay. Food Chem Toxicol 2007;45:662-666.
  11. Stevia doesn’t appear to damage DNA in mice. Sekihashi K, et al. Genotoxicity studies of stevia extract and steviol by the comet assay. J Toxicol Sci 2002;27 Suppl 1:1-8.
  12. This study concluded: “Stevioside at a dose as high as 2.5 g/kg body wt/day affects neither growth nor reproduction in hamsters.” Yodyingyuad V, et al. Effect of stevioside on growth and reproduction. Hum Reprod 1991;6:158-165.
  13. The study says that humans and rats metabolize stevia similarly. Koyama E, et al. Absorption and metabolism of glycosidic sweeteners of stevia mixture and their aglycone, steviol, in rats and humans. Food Chem Toxicol 2003;41:875-883.
  14. Stevia may decrease fertility in male rats. Melis MS. Effects of chronic administration of Stevia rebaudiana on fertility in rats. J Ethnopharmacol 1999;67:157-161.
  15. This study says maybe not. Oliveira-Filho RM, et al. Chronic administration of aqueous extract of Stevia rebaudiana (Bert.) Bertoni in rats: endocrine effects. Gen Pharmacol 1989;20:187-191.

The verdict

In preparing this article, we read through quite a bit of stevia information. And the balance of it suggests that in low-moderate doses, stevia probably won’t cause any health problems.

Although, we should mention that some of the toxicity data is odd. And some of the DNA damage info is enough to give one pause. So, our advice to you is this: Apply for grant money so you can do more stevia research.

Ok, ok. If you don’t get around to doing that, then consider your overall stevia use. If it’s moderate, you’re probably fine. However, just like with other sweeteners, problems can probably develop at higher doses.

For what it’s worth, we here at PN aren’t moved by stevia either way. Just like with Splenda, the research doesn’t convince us that there’s any need for fear or paranoia. Nor does the research convince us that stevia (or Splenda) is friendly, helpful, or necessary.

A little bit of it each day in some tea, coffee, oatmeal, or a protein shake is probably fine. But we wouldn’t break out the stevia cookbook just yet.

What about my cookies?

But what if you want some cookies – and you want them sweet? We say, make some real cookies. And eat them infrequently.

Use a whole grain flour, unrefined sweetener (like date sugar or evaporated cane), and other healthy organic ingredients. And then eat them after exercise, with a PW meal.

That way, you get something sweet, get some quality nutrition and don’t have to second guess your use of “alternative” sweeteners. Gourmet Nutrition and the Gourmet Nutrition Desserts books have quite a few ideas on this front.

However, just like with stevia, Splenda, etc, you’ve got to be careful with ALL sweeteners. Even with the “natural” ones – date sugar, cane, etc. – overindulgence can lead to fat gain, blood sugar swings, and problems with insulin sensitivity.

So your best bet is to get control of that sweet tooth.

No, you don’t have to eliminate sweet things altogether. Yet keeping your sugar and sweetener use in check is one sure-fire way to improve your health and body composition.

References

Click here to view the information sources referenced in this article.

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