Friday, August 25, 2017

What You Thought You Knew about Artificial Sweeteners

Are Artificial Sweeteners a Sign of the Apocalypse?

I have a chemistry minor and a biology major.  Most people don't.

With that out of the way, let me be frank in the observation that most of the things people tell you are wrong.  I have found it nearly axiomatic that nearly all things people tell you about diet and health are wrong, sometimes so stupendously, irresponsibly wrong as to constitute wrongdoing.  

Sometime in 2013 my dad came home from work and even before grabbing a beer, seized a box of Splenda from the pantry said, "We gotta throw this stuff out.  That stuff's poison.  I heard it on the radio on the way home."

The things that people say about artificial sweeteners fall under this category.  My dad was not alone in his uncritical acceptance of the proposition that artificial sweeteners like Splenda are "poison" or carcinogenic.  So let me take the opportunity to school you on this unique and misunderstood class of compounds.
Image result for sucralose microscope
At left is common table sugar.  You can easily make out the cubic crystals.  The ones at right are crystals of Splenda, whose main component is sucralose.

Sugars Vs. Non-Sugar Sweeteners

First, a few notes on sugars.  Yes, I said "sugars."  There are hundreds of known of sugars, and we can broadly define sugar as any water-soluble short chain or cyclic carbon-based compound with multiple hydroxide groups, for which the ratio of carbon to hydrogen to oxygen is generally 1:2:1.  So you can have C3H6O3, or C7H14O7, or glucose, whose formula we learned in middle school science is C6H12O6.  Most sugars have names that end in "ose," such as glucose, lactose, and sucrose.  Sugars are carbohydrates and supply living things with quick access to cheap calories.  They can make long chains called polysaccharides, more commonly known as starches.  There are usually about 3.9 nutritional calories in a single gram of sugar.  Many sugars taste sweet.

From left to right, we see a lactulose- a disaccharide, and glucose and fructose- monosaccharides.  Table sugar (sucrose) is a common disaccharide.  The sugar in your blood is modulated by glucose.  Most sugars have ring structures.  The grey is carbon; the white is hydrogen; and the red is oxygen.

Non-sugar sweeteners comprise a wide and diverse menagerie of organic, or carbon-and-hydrogen-based, compounds, most of which are derived from glucose or sucrose, although many have more exotic origins (such as mushrooms).  Some artificial sweeteners are sugars; others are non-sugars.  A natural non-sugar sweetener such as stevia or erythritol is usually referred to as a "sugar substitute," while sweeteners made in an industrial chemical process, such as saccharine or Splenda, are called "artificial sweeteners."  Here we will focus on the latter, as they lie at the center of much more controversy and misinformation than benign ol' stevia.  Artificial sweeteners are often made by taking sugars and shotgunning them with a variety of catalysts and extremes of temperature and pressure.  In the case of Splenda, sugars are force-chlorinated in towering pressurized tanks to produce sucralose.  Trucks come in bearing sugar, they leave with loads of Splenda.  (However, the marketing slogan "It's made from sugar, so it tastes like sugar" is bullocks on a few levels, not the least of which is the fallacy that a derivative tastes like what it is derived from.  Do you suppose that manure really tastes like grass?  "It's made from grass, so it tastes like grass" is clearly not true in this case.  But we are barely a short way in and I am already on an unproductive tangent.)  Because artificial sweeteners are man-made and are considered food additives, they must be tested and approved by the Food and Drug Administration or (if not in the US) other food safety authority.  Stevia and the like get around this by being essentially "herbal," which means their safety is actually much more questionable than FDA-approved sweeteners.  I'm just being honest here.

From left to right we see aspartame, sucralose, and saccharine.  All of them maintain the basic ring structure found in nearly all sugars, but they have extra chemical groups attached that stimulate your taste buds.  (The scientific community is still a little confused about how and why they work on the human tongue.)  The same colors apply as the ball-and-stick models of sugars above, but here blue is nitrogen; green is chlorine; and yellow is sulfur.  Most artificial sweeteners have one or more of these added chemical groups.

First, why are artificial sweeteners non-caloric?  What about them makes a soda "diet"?  It is common to suppose that the body somehow "cannot process" or "absorb" these compounds, so they leave the body without contributing calories.  But the truth is that they certainly possess calories that are able to be absorbed by the body.  Indeed, a gram of pure aspartame has about the same energy content as table sugar.  But the sweetness of, say, sucralose (the main component in Splenda) runs about 1,000 times that of table sugar, while saccharine runs at 300 times, and aspartame at about 200.  Stevia and erythritol don't run as high but are almost non-caloric.  So instead of using, say, 60 grams of sugar per 8 ounces of soda, we can use 0.060 grams of sucralose, which possess maybe 0.2 calories, and be done with it.  Artificial sweeteners aren't actually non-caloric; they are instead super-sweet, and so their caloric contributions to food and drinks is negligible.


Why We Think that Artificial Sweeteners Will Not Kill You

Next, why the bad reputation of artificial sweeteners?  The most common, and almost absurdly ignorant, mis-belief is that they cause cancer in humans:

"There was a study," someone assures me, "A study done in the 70's, I think, on rats that shows that aspartame [or saccharine, or whatever] causes bladder cancer."

"I read that study," I respond.  "Did you know it was debunked based on its poor methodology only a few years after it was published?  Did you know that they fed the rats absurdly huge quantities of aspartame, more than any human could possibly consume?  Did you know that rats produce a unique compound in their urine that crystallizes with aspartame's metabolites and causes bladder ulcers, which are precursors to cancer?  Did you know that the same study done on mice showed no such result because mice do not produce said compound, and the same with gerbils, guinea pigs, cats, horses, monkeys and even humans? Did you know that the huge bulk of subsequent studies [like this one, and this one, and the European Food Safety Authority (they ban everything) and this government health resource] indicate no connection between human consumption of artificial sweeteners and the incidence of cancer?  Even this study shows that Splenda in particular has no such impact on rats."

"Aspartame turns into formaldehyde when it is metabolized," he says.

"Yes.  Aspartame is metabolized into some amino acids and a small residual amount of formaldehyde.  Did you know an orange has 600 times as much formaldehyde in it than a can of diet Pepsi?  Did you know that formaldehyde's cousin acetaldehyde is produced as an intermediate in the metabolism of alcohol?  You should stop drinking all alcohol and orange juice.  Definitely no more screwdrivers."

Silence.


***

The science is really unequivocal on this: artificial sweeteners are not known to cause cancer in humans, period.  Aspartame itself is one of the most rigorously tested and studied substances the FDA has ever approved.

If this bothers you, then I advise you do what I do: ease up on the soft drinks.  I hardly ever drink any sort of soda because it is so bad for my teeth.  Plus, if you drink regular soda, it's gut-punching your pancreas as it is metabolized.  I go for flavored seltzer water, like the stuff made by La Croix or Kroger.  Even Dry is a less sugary alternative.  These fizzy drinks are super delicious, refreshing, and you don't have to suffer the guilt of consuming extra calories or chemicals you suspect of causing cancer (even though you're wrong about that last part).

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