Lecture 5: Demystifying Your Ingredients - Sugar Substitutes (Part I)

A while back, when we baked our unbelievably sweet Pumpkin Cinnamon Rolls, we told you a little about the magic (and science) of sugar.  Sugar is the compound that makes us sense sweetness, the stimulus that, in its purest sense, signals the presence of nutrition in food.  This is why sugar tastes so good - it encourages use to eat foods that will provide us with energy.

Figure 1.  The molecular structure of sucrose.  The hexagon
on the left is glucose, and the pentagon on the right is fructose.
 Each corner of each shape is a carbon (except for the two
oxygens).  The two sugars are connected by an oxygen
atom.  This atomic grouping (C-O-C) is called an ether group.

Sugar comes in many forms.  Glucose is the most basic sugar - through a series of biochemical and electrochemical steps, our bodies convert it into ATP, our body's molecular batteries.  Sucrose, or table sugar, is a disaccharide (composed of two sugar units), made of glucose and fructose, another natural sugar.  There are two major problems with sucrose.  First, it has a lot of food energy, or calories.  Another issue: it's converted to glucose in the body, which in diabetics can thicken the blood, increase blood pressure, and cause tissue damage in delicate areas such as the fingers, toes, and eyes.  Over the years, scientists have therefore come up with several sugar substitutes that solve one or both of these issues...and some have worked out better than others.

We are going to start our venture into the world of sugar with a study of those that you won't be able to find anywhere because they're either horribly toxic or just outright banned by the FDA.

Lead Acetate

Figure 2. Lead (II) acetate.  DON'T EAT THIS.

Surprisingly, lots of lead salts (lead + acid) taste sweet.  The ancient Romans noticed this, and they came up with the bright idea of using lead (II) acetate, the same compound in those paint chips you're not supposed to eat, to sweeten their wine.  Sure, at the time, they didn't have many sweeteners at their disposal, so it is understandable they they'd use any remotely sweet compound that they could get their hands on to obtain their sugar fix.

But, as you can probably guess, the Romans ran into problems.

Lead is a poison - it binds to most of the enzymes (the "workers") in your body and renders them nonfunctional.  It's half-life in the body is about a week, so repeated exposure will cause it to build up in the body, which leads to neurodevelopmental impairments and organ failure.  Now, it is still under debate whether lead poisoning was a significant public health issue in the Roman Empire, and if it was, whether lead acetate was responsible (they used lead pipes, too, remember), but it is known that lead acetate led to the deaths of Pope Clement II, the painter Albert Christoph Dies, and possibly Ludwig van Beethoven.  Don't worry, lead acetate has been banned from foods in the US and Europe for a looong time (but not some hair dyes; FDA 2002)


Cyclamate

Figure 3. A juice powder packet from the early seventies.

Cyclamate's sweetness was accidentally discovered by a student at the University of Illinois after he synthesized it in 1937 (what's with everyone tasting random compounds??).  Its patent was bought by Abbott Labs and was used to mask the taste of some of their bitter antibiotics.  In the 50's and 60's, cyclamate was sold in tablets and was used as tabletop sweetener for diabetics (similar to how Splenda is used today).  In 1969, a study came out showing that cyclamate caused bladder cancer in rats, and this study led to the FDA to ban the sweetener (FDA 2014).  However, it turns out that this study was plagued with problems.  For instance, the researchers used an extremely high dose of cyclamate in a species that was already highly susceptible to bladder cancer.  Since then, dozens of studies have come out that demonstrated the safety of cyclamate.  Consequently, an application has since been submitted to the FDA to get cyclamate re-approved.

As we all know, the government moves very slowly, so it might be a while until you see cyclamate back on the table at your local deli.

Stay tuned for Part II - Natural Sweeteners

Figure 4.  Yummy donuts.

Sources:
FDA, 2002: http://www.fda.gov/Cosmetics/ProductsIngredients/Products/ucm143075.htm
FDA 2014: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=189.135