Natural Sugar Alternatives and Substitutes

Before we start, we find http://www.sugar-and-sweetener-guide.com/ with its sweetener values to be a great web resource. Our kudos and personal thanks to whoever is running it.

Glycemic Index
Let’s start with another definition: Glycemic Index.

Glycemic Index is a relative measure of how quickly a given food raises the glucose level in the bloodstream (aka blood sugar) after being ingested. And it’s a relative measure because it is relative to pure glucose, which is taken as 100.

Foods with GI over 70 are generally considered to be high glycemic index. Foods with GI of under 55 are viewed as low glycemic index. These are pretty good points of reference.

Sadly, Glycemic Index does not tell a full story. In a way it tells you how fast you’re going, but not where. For example, fructose has a GI of only 23, which would put it seemingly in the “healthy” range. And it is this very fact that is used by agave and high fructose corn syrup peddlers to insidiously market fructose as a safe low glycemic alternative. All the meanwhile, fructose raises the insulin levels (insulin is the hormone that helps remove glucose from the blood), ultimately leading to insulin resistance and ability to control blood sugar and remove excess glucose from the bloodstream. Furthermore, the elevated insulin levels mask leptins (satiety hormones released when we are full) from the brain, so on sugar, we keep thinking we are starving.

The point is, Glycemic Index is a good guideline, but in and of itself, it’s not enough.

But in general, the lower a given food’s GI, the better.

Inulin (oligofructose)

If you were to look up various common sugars, you’d get a litany of vaguely familiar words that all end in –ose.  Lactose, glucose, fructose, sucrose, maltose, even galactose. If you were to dig a tad deeper, you’d find they each have a different sweetness, and all but fructose are less sweet than table sugar.  They also have a range of glycemic indexes from the seemingly OK to very high.  And you probably already know that lactose is the natural sugar in milk, and maltose has something to do with brewing. So what?

There isn’t much to add here without going head-first into chemistry.  Galactose, glucose and fructose are called monosaccharides because they each consist of a single ring.  Galactose and glucose have 6 members (hexagons) and fructose has 5 (pentagon).  These guys can be attached together in different permutations of two rings, which are then called disaccharides. Sucrose, as you already know, is glucose bound to fructose. And when galactose is bound to glucose, that’s lactose. When two glucose rings are linked to each other in a certain way, that’s maltose. When they are linked in a slightly different way, the molecule is called trehalose. And so on.  Some of that will become important when we talk about sugar alternatives below.

Our body can pop the bond between the two sugar rings pretty easily. When there are more than two, it becomes increasingly difficult and when the chain gets too long, we cannot process it and excrete it as insoluble fiber.  That’s simplifying things a bit, but that’s close enough.

Don’t believe me? Go bite a two by four, swallow and see what happens. Or chew on some paper. That’s cellulose. It’s fiber or a very long molecule made up of thousands rings of glucose linked together into what is called a polysaccharide. The smaller ones are called oligosaccharides.  And the mono- and di- we already talked about above.

It turns out, our bodies process these oligosaccharides quite a bit differently than the simple sugars (di- and mono- saccharides).  The body’s ability to break them down depends on the length and linkage types between the individual rings.  That is because the chemical arrangement of the individual rings into chains affects their solubility in our bodies and in other solvents as well. For example, under common conditions of our organism, cellulose is insoluble.  But if you were to tweak the way those rings are attached to each other, you could get pullulan, a perfectly soluble, though tasteless, material approved for food and drug use by FDA and similar agencies across the globe.

The truly interesting stuff happens with the lower oligomers or smaller oligosaccharides. They still retain some of their parent ring sweetness while dropping their negative health effects.  These oligosaccharides are commonly derived from chicory root (or the agave cactus – but NOT to be confused with the agave syrup, which is poison).  As soluble fiber, they help with clensing out you digestive tract. They have good prebiotic properties to boot, helping the promotion of the good bacteria in your gut.

So, it is not surprising then, that lately, these oligosaccharides have been inching their way into the marketplace in the USA as sugar substitutes. They are called inulin (or oligofructose in smaller print.)

Chemical Structure of Inulin

They are perhaps the healthiest alternative to sugar.

So, what’s the problem then?  

Two problems, actually, but neither insurmountable. Because they are not isolated as individual chains – think of what it’s like to sell worms of exactly the same length for bait. Some worms are shorter, some are longer.  Some disaccharides and monosaccharides sneak in. The more of that monomer and dimer, the sweeter the taste.  Without any of those smaller sugars, oligofructose will only taste 1/5 as sweet as sugar. Slightly sweet.  

Now, let’s not overreact here. 5% of glucose in inulin ain’t gonna kill you. Heck, if you eat bell peppers, there’s 3%-5% sugar in pepper.  So, if you eat a pepper weighing a third of a pound, you are not going to die of fructose poisoning.  Why? Fiber. You are eating a negligible amount of sugar with a ton of fiber, remember?  Same with inulin.

You just have to (1) continue reading the label to see how much mono and disaccharides have snuck their way into your inulin and we aware and (2) realize that inulin alone ain’t gonna give you the sweetness of sugar to which you’ve grown addicted in the past.

There is actually another slight problem with inulins, but that only affects the cooks. If you bake with inulin alone as sweetener, the food will come out dry.  That is because the fibers cannot hold as much moisture as sugar.  There, fructose is tough to replace.  (Until we came along with our – shameless plug – Sweet LUV).

Sugar Alcohols

This table comes from http://www.sugar-and-sweetener-guide.com and has been modified ever so slightly to reflect the wider ranges for some sugar alcohols found in literature. It’s a pretty good reference, but it excludes the glycemic load parameter. Glycemic Load takes into account the total carbs per serving in addition to the glycemic index of the food. So that way it adjusts whether you have a teaspoon of erythritol vs half a pound of bananas.

What defines sugars chemically (apart from the literal commonality of the –ose ending) is that they are all aldehydes in one form or another. That is not to say that all aldehydes are immediately bad or that anything that is not aldehyde is good, but it’s a commonality that results in similar reactivity in the body and similar reactive pathways in some of the metabolism of these molecules. However, as we have already seen, though fructose and glucose are both aldehydes, they are metabolized quite differently in our bodies, right?

Structurally, an aldehyde will have a hydrogen bonded to a carbon (H-C)  (aka hydrocarbon) which has in turn a double bond to an oxygen (aka a carbonyl group) (H-C=O). Because carbon needs four bonds to be happy, it is bonded to some other group as well, and it is the different nature of these other groups (we call them R generically in chemistry) that imparts its own individual flavor upon every aldehyde: H-C(R)=O.

So, a carbonyl with a terminal hydrogen is called an aldehyde. And that is one structural commonality of these aldehydes: this reactivity of the terminal hydrogen H in the H-C=O.  That hydrogen is also acidic, which accounts for some of its reactivity and the larger metabolic sugar biochemistry in general and tooth decay (acid eating away the tooth enamel) in particular.

When the double bond between carbon and oxygen is reduced, which is to say, when the carbonyl is saturated to form an alcohol, the resultant molecule loses its reactivity: it is no longer acidic, nor is it any longer an aldehyde.  That reduction or saturation happens naturally in the metabolic pathway of sugars to produce sugar alcohols.  So, sugar alcohols are (1) natural and (b) lack the acidity and reactivity of their parent sugars.  Of course, we, humans, as clever as we are, have learned to do this reaction outside of our bodies to produce naturally occurring sugars like maltitol (derived from maltose), erithritol (derived from glucose), xylitol (derived from xylose or tree sugar), sorbitol and mannitol  (both derived from fructose) and so on.
Graphically, chemists depict this process thus:

Chemists love short cuts, especially the biochemists, and in the reaction above instead of carbon being represented by a letter C, it is implied by a kink in the chain.  So, every time you see a bend, that’s a C with enough hydrogens on it to ensure four bonds per every carbon.  (So every time you see HO- alcohol, at the end of the dash is a -CH2-, or a carbon with 2 hydrogens on it).

You will notice that the carbonyl (C=O) part of the aldehyde group is reduced to a corresponding alcohol.  So, the sugar, which already had 4 alcohol groups on it, now gets a fifth one (in blue) and because that structure is no longer dominated by the aldehyde (red) functionality, it is called a polyol or sugar alcohol.  

If you count the carbons on either xylose or xylitol, you should get 5. Xylose is a 5 carbon sugar and xylitol is a 5 carbon sugar alcohol.  That make sense, right? Because the carbons were not affected by the conversion of sugar to its alcohol. Sometimes, however, the number of carbons is not preserved.  That happens when it’s commercially cheaper to make the sugar alcohol from a larger (more carbons) sugar and let the bacteria metabolize the sugar into a smaller sugar alcohol.
That happens when erythritol (4 carbon sugar alcohol) is made from glucose (6 carbon sugar).

By the way, at first glance, inulin might too appear to be a sugar alcohol, just a very long one.  Why, with all of its OH (alcohol) groups and no aldehyde to be found anywhere in its structure, why wouldn’t it be? Yet, it isn’t.  When sugars are drawn in their “closed-ring” form, the aldehyde is not visible, but readily formed. If you are confused, that’s OK.  That’s why organic chemistry and biochemistry in particular isn’t simple or easy to explain.  It’s complicated.  But it’s still true.

So this is the hardcore “sciency” stuff. Now come the consequences, some of which are unintended consequences.

 

Maltitol and Isomalt

Unlike inulins, sugar alcohols do carry a glycemic load.  So here not all sugar alcohols are alike. In fact, one of the most commonly used sugar substitutes  in the chocolate and candy industry is a sugar alcohol called maltitol. If you glance at the structure of maltitol:

Maltitol

You might notice there’s something wrong. For one thing, it’s not a simple chain of hydrocarbons (CH’s) with alcohols (-OH) bound to them. I mean, it has that on top, but that top is bound to something that looks remarkably like a six-member ring. In fact, it is a six member ring, and in fact, that ring is known as glucose or sugar.  So, maltitol is, in fact, a sugar alcohol bound to a sugar. That is why its Glycemic Index is the highest of all the sugar alcohols: when that ether linkage (-O-) connecting the sugar alcohol chain to the glucose ring is popped (and it gets popped first upon ingestion), glucose is released. And glucose, remember, has a GI of 100. So half of that maltitol molecule is, indeed, sugar.

If we look at how maltitol is made, it all becomes clear: maltitol is made from maltose, which is two glucose rings bound together by that ether (-O-) linkage.

When maltitol is made from maltose, only one of its glucose rings is hydrogenated or reduced or converted from glucose to mannitol or sorbitol. And when that maltitol hits our digestive system it is instantly converted to its two components, glucose, which is sugar, (in red) and a mixture of sorbitol and mannitol sugar alcohols (in blue). Sorbitol and mannitol have identical structures, except one is a mirror image of the other, and that sterochemical difference is not critical here; it is sufficient to understand that maltitol upon ingestion falls apart to give equal amounts of glucose and sugar alcohols:

Initial Metabolic Breakdown of Maltitol

And it is this glucose sugar in red that gives rise to the blood sugar levels and accompanying high glycemic index to maltitol.  Maltitol is only half sugar alcohol and half sugar.

Isomalt is another sugar alcohol that has a very similar structure to maltitol above.   

And even though its Glycemic Index is very low and on par with erythritol, today’s “trendy” sugar alcohol, I’m rather suspicious about what else this particular sugar alcohol might do when it’s metabolized to glucose and sorbitol/mannitol mixture upon ingestion.  That glucose has to go somewhere.  We are fortunate to live in the age when our metabolic and biochemical knowledge is exploding, so I am confident that research is being done and will be done to further elucidate the effects of sugar alcohols on our blood sugar levels and longer term effects of sugar alcohols.

Xylitol

In that regard, xylitol is perhaps the safest and the longest-studied sugar alcohol or sugar substitute out there. Since its discovery nearly 125 years ago, xylitol has become the most studied sugar substitute on the planet. Its positive dental effects are well documented from the famous Finnish studies in the ‘70s to to the now folkloric “4 out of 5 dentists” recommending xylitol-sweetened chewing gum for their patients in a classic advertising slogan.  Among its two negative effects are: (1) its lethal to dogs – even small ingested amounts reak havoc on their blood sugar levels and in larger doses cause liver failure.  Remember, your liver is your last line of defense against toxins.  (2) Larger amounts cause digestive discomfort in some humans.

The second one is easy: a number of studies have shown that gradual increase in daily consumption of xylitol makes any gastric discomfort fade. In one study, xylitol intake was gradually increased to nearly a pound per day with no negative gastrointestinal effects. In defense of xylitol it should also be said that any food, never mind sugar, when pushed to excessive consumption, may and will cause gastrointestinal discomfort.  Think of last Thanksgiving. There you go.

Still, some people have more acute responses to xylitol spikes in their diets and will eschew xylitol, favoring erythritol in its stead.

There are a number of manufacturers marketing xylitol sweetened just about everything, from ice creams to chocolates, but the discerning palate of a chocoholic can tell, right?  Xylitol is surely a part of the answer, but not the entire answer.  Sweetness (vs sucrose) = 1; GI = anywhere between 7 and 12, depending on your sources.

Erythritol

Erythritol is great in many regards. For one thing, unlike other sugar alcohols, even excessive consumption of erythritol has not been shown to cause gastrointestinal discomfort. Thus far. Thus far, that is. There will be somebody, mark my words.  

However, unlike xylitol, which has the same perceived sweetness as table sugar, erythritol is (1) only half as sweet.  Another drawback (2) is its cooling effect in the mouth. While that’s fine in some foods, in others it tastes nothing like sugar. Also, (3) it is not very friendly in baking: of all the sugar alcohols it is one of the least hydroscopic, or least hydrophilic. What that means to you as a cook is that your erythritol-sweetened brownies or scones or cookies will come out way drier than the sugary ones.  A small price to pay, to be sure, but a price that’s worth mentioning.

Also worth mentioning is that erythritol is frequently paired with Stevia by the larger manufacturers. More on that in the Stevia section, but the two compliment each other nicely.

Other Low Glycemic Index Natural Sweeteners

This is, admittedly, a catch-all category for other natural sweeteners that do not fit into either the inulin/oligofructose or the sugar alcohol category.  We are consciously excluding natural sweeteners based on mono- or di-saccharides containing fructose like agave, agave syrup, honey, palm sugar, molasses, maple syrup and concentrated fruit juices. All these are essentially concentrated solutions of table sugar with varying amounts of vitamins or nutrients added to the fructose poison. In other words, if you screwdrivers and bloody maries are not a good place to get your Vitamin-C. Sorry. And that applies to Necresse, the natural sweetener loosely based on monk fruit which the Splenda people have been peddling. More on that below.

Some sources prefer to group the aforementioned fructose embodiments as natural sweeteners, but all of them are a BIG No-No’s for diabetics for all the reasons we already discussed.  In this category of low GI natural sweeteners we put stevia in its many forms and Monk Fruit/Luo Han Guo – these in a way are oligoglucose of inulin, except that in inulin it is (1) the same repeat unit structure of (2) fructose that repeats multiple times in a long chain.  In stevia and Monk Fruit extract (1) far fewer repeat units, typically a dimer (2 repeat units) or a trimer (3 repeat units) of (2) glucose are bound onto the (3) core substrate, attaching one of the di-/tri-mer glucose molecules to the core in an ether linkage.  In stevia, rebaudioside A and stevioside, the two sweetness imparting components, are also glucose esters of the acidic steviol core:

Stevia

Steviol “core” or substrate onto which glucose molecules are bound in stevia sweeteners

Structural formula of rebaudioside A, key sweetness imparting component of Stevia

Stevia is listed as having zero Glycemic Index and sweetness 100 to 300 times that of table sugar or sucrose.  

What could be better, right? Finally, an all-natural plant derived (stevia has been extracted from a plant leaf found in South America for centuries) extract that is way sweeter, yet completely harmless!   

One of the most commonly heard complaints about stevia sweeteners heard from discerning sugarholics is that it has a bitter aftertaste. That, and that their palates are so sophisticated and discerning that they can immediately pick out stevia in any thus sweetened drink and or food.  And while that might be true in some cases, more often than not, stevia is misused because it is mis-measured.

Let me explain.
Let’s imagine brewing a fresh pot of coffee first thing in the morning. Let’s also assume that to lighten your coffee, you take a dash of half and half, which is thus named because it’s made of equal parts of milk and cream.  Normally you take a spoon of sugar, or, rather you used to before you started reading the alarming information about the dangers of fructose. Now comes the fun part. How do you measure a teaspoon of sugar equivalent in stevia?

Stevia is 300 times sweeter than sugar, so you will need 1/300 or 0.003 of a teaspoon. How the heck do you measure that in your kitchen? Especially BEFORE your first cup of coffee.  It gets tricky.  In your half-awakened state you suddenly realize while you rummage through your utensil drawer that even if you did have a three-one-thousandth teaspoon measuring spoon, it would be impossibly small to find with your eyes still closed.  

No, seriously, we cannot measure 3/1000 of a teaspoon in our kitchens.  And when taken too strong a concentration or in excessive amount, stevia does have an odd, even bitter aftertaste.

To battle this issue some manufactures have been pairing stevia with erythritol. That’s OK, as long as you realize that you are consuming essentially straight erithritol with a hint of stevia.  And if you remember reading about erythritol earlier, you will recall its own set of issues: it tastes strange with a cooling effect and it is only half as sweet as sugar. Just as it is challenging for you to measure 3/1000 of a tablespoon of stevia, it is difficult for manufacturers to have a mixture where its 0.003 parts component is dispersed uniformly enough so that your every teaspoon tastes as sweet as sugar and not only half as sweet.  Worse than that, the poor hydroscopic properties of erythritol make it difficult for it to replace sugar in baking and cooking recipes.

All of this is problematic, but not insurmountable.

What’s worse is that in many stores throughout Midwest we’ve seen some manufacturers and compounders of stevia, blend it with maltodextrin without adequately disclosing it on the label. You have to read between the lines to realize it. You have to figure it out in the fine print. So the folks who think they are sweetening with stevia, are in fact sweetening with >99% maltodextrin without realizing it.  Maltodextrin, especially when it’s wheat-derived, comes with its own slew of health issues and concerns for the discerning. 

Monk Fruit/Luo Han Guo

The sweetness-imparting components in Luo Han Guo or Monk Fruit are a mixture of oligo-glucose ethers (glycosides) of various cucurbitanes whose structure is highlighted in blue in the figure below.  Those sugar ethers are called mogrosides. Pictures is mogroside-5, where the number 5 denotes the sum total of the glucose molecules bound to the cucurbinate core. In this case there are 3 glucose molecules on top, highlighted in yellow and 2 on the bottom, also in yellow, for a total of five. Mogroside-5 is the sweetest one in the mixture that also contains mogroside-2 (1 glucose ether on top and 1 on the bottom) and mogroside-6 (3+3 glucose molecules).

Structural formula of mogroside 5, key sweetener in monk fruit

As the name Luo Han Guo suggests this sweetener comes to us from China and at the moment is heavily promoted by the Splenda people under the trade name of Nectresse.
Luo Han Guo is only the third component in that mix, coming after erythritol and…wait for this…sugar. So, sugar is the second largest component in the mix, and for good measure the manufacturers of Nectresse also added molasses (another high fructose sugar).  Fructose in sugar and in molasses make this sweetener highly suspect. We are not sure why Splenda decided to compound their Luo Han Guo with sugar, but in our opinion, it was completely unnecessary and addition of sugar and molasses de facto ruins the very premise behind Luo Han Guo.

However, there are other sources to get your Luo Han Guo straight, without the fructose dilution by Splenda. If you can get your hands on it, it might be worth trying. Straight Monk Fruit sweetener is 100 to 300 times sweeter than sugar, depending on the ratios of various mogrosides present in it.  With straight Luo Han Guo, the same measuring issues arise: how do you measure one-three-hundredth of a teapsoon at home?  Splenda wants you to do that by diluting it with sugar and erythritol, but is that not too heavy price to pay?

In short, be careful and vigilant with this one, and always read the label.

Yacon Syrup

Yacon syrup hails from Peru. It is a version of oligosaccharide is extracted out of the root of a yacon plant, which is said to taste like an apple, but sweeter.  If that sounds similar to inulins from the chicory root, it is.  

The syrup obtained from yacon root is half is also half as sweet as sugar, just like the sweetest of inulins from the chicory root.

At the time of this writing there appears to be a supply problem of this material from Peru: none of the webstores in the United States seem to have any in stock. This sweetener has not yet gotten a foothold in the American sweeter market at the time of this writing, and we very much look forward to evaluating it in our products in the near future.