In pursuit of sweetness

In our wheat-free lifestyle, having an occasional sweet indulgence can be nice. Recipes such as cheesecake or cookies, for instance, require some amount of sweetener. So how can we choose our sweetener and minimize adverse physiologic consequences? Understanding the use of these benign sweeteners can be especially helpful for holiday cooking, entertaining family and friends, and an occasional indulgence. (Surely you’ve tried my Pecan Streusel Coffee Cake!)

Pick sucrose and we are exposed to the 50% fructose contained in the glucose:fructose molecule. Fructose is so awful at so many points in metabolism that it is worth absolutely minimizing.

There are several good choices but navigating among them is often confusing. Be aware that non-nutritive sweeteners, due to their sweetness, have the potential to increase appetite. Use these sweeteners sparingly, adding only enough to make your recipe slightly and pleasantly sweet. Thankfully, the majority of people who are wheat-free experience heightened sensitivity to sweetness and the need for sweeteners of any sort diminishes over time.

Stevia
While stevia has been around in the U.S. for decades as a “nutritional supplement,” it recently received a boost into mainstream use with the FDA’s “Generally Recognized As Safe,” or GRAS, designation in 2008 for its rebaudioside component, also known as rebiana. Agribusiness giant Cargill (yeah, yeah: I know!) launched its Truvía brand, which contains erythritol with rebiana, while PepsiCo launched PureVia, a combination of erythritol, rebiana, and a small quantity of the sugar isomaltulose.

Stevia plants are naturally sweet, often called “sweet leaf.” Some people grow the plants and chew the leaves for their sweetness or add the leaves to recipes.

Stevia is also widely available as powdered and liquid extracts that, in addition to the rebiana, have the other sweet components of the stevia leaf. Many of the powdered extracts are made with maltodextrin, erythritol, xylitol, or inulin to add volume or to mimic the look and feel of sugar. Maltodextrin is a polymer of glucose produced from corn or wheat. The maltodextrin may therefore represent a potential source of wheat gluten exposure for people who are extremely sensitive. Maltodextrin is also a source of calories, since it is essentially a chain of glucose molecules. While glucose provides 16 calories per level teaspoon, maltodextrin is digested less efficiently, it provides less than this but is variable depending on the length of the glucose chain. Stevia in the Raw brand made with maltodextrin and rebiana therefore lists less than two calories per teaspoon on its nutritional composition. Note that two calories per teaspoon equates to 96 calories per cup, or a total of up to 24 grams carbohydrates per cup. Carbohydrate exposure is therefore a concern when large quantities are used. Ideally, use the stevia extracts that are pure stevia or made with inulin, e.g., Trader Joes, SweetLeaf brand. Maria Emmerich advises me that the stevia glycerite form is less bitter for many people.

Liquid stevia extracts are highly concentrated with little else but stevia and water. The quantity required to equal the sweetness of sugar varies from brand to brand. The SweetLeaf brand, for instance, claims that two drops of their Stevia Clear extract equals one teaspoon of sugar, while some other brands require five drops for equivalent sweetness.

Because of the variety of ways stevia is purified and packaged, you will need to adjust the volume of powder or liquid used depending on the preparation. Most preparations will provide advice on what quantity matches the sweetness of sugar. Also, the presence of other ingredients like erythritol or maltodextrin can influence how various recipes respond; some experimentation may therefore be necessary, especially when trying a new brand of sweetener in a recipe. For instance, erythritol combined with stevia, e.g., Truvía, may not hold up as well in baking and can acquire a slightly bitter taste.

Xylitol
Xylitol is a form of “sugar alcohol,” i.e., a carbohydrate with an OH group attached, thus the term “alcohol,” a confusing designation as it contains no ethanol (the alcohol in a martini or glass of wine) nor shares physiologic effects of ethanol. Xylitol is found naturally in fruits and vegetables. It is also produced by the human body as part of normal metabolism.

Teaspoon for teaspoon, xylitol is equivalent in sweetness to sucrose. It yields two thirds of the calories of sucrose and, because digestion occurs in the small intestine rather than the stomach, triggers a slower and less sharp rise in blood glucose than sucrose. Most people experience minimal rise in blood glucose with xylitol. In one study of slender young volunteers, for instance, six teaspoons of sucrose increased blood sugar by 36 mg/dl, while xylitol increased it 6 mg/dl. Interestingly, several studies have demonstrated positive health effects, including prevention of tooth decay and ear infections in children, both due to xylitol’s effects on inhibiting bacterial growth in the mouth.

Xylitol can be used interchangeably with sugar in recipes. It also has the least effect on changing baking characteristics. While traditionally produced from birch trees, more recent large scale production uses corn as its source. (While I am no fan of corn, particularly genetically-modified corn, the purified xylitol is likely not a substantial exposure to anything but the xylitol.)

Erythritol
Erythritol, like xylitol, is a naturally occurring sugar alcohol, i.e., a carbohydrate with an OH group attached and thereby labeled an alcohol, though it has nothing to do with ethanol. It is found in gram quantities in fruit. In commercial production, erythritol is produced from glucose with a process using yeast. Also like xylitol, osmotic gas and bloating generally does not occur as it does with common sugar alcohols mannitol and sorbitol.

Over 80% of ingested erythritol is excreted in the urine, the remaining 20% metabolized by bacteria in the colon. For this reason, it yields no increase in blood sugar even with a “dose” of 15 teaspoons all at once. There are less than 1.6 calories per teaspoon in erythritol. Limited studies have demonstrated modest reductions blood sugar and hemoglobin A1c (a reflection of the previous 60 days’ blood sugar) in people with diabetes who use erythritol.

Erythritol is somewhat less sweet than table sugar. It also has a unique “cooling” sensation, similar to that of peppermint, though less intense. It may therefore confer a cooling sensation to your baked products. It also does not hold up in baking quite as well as stevia. When Truvía was used in testing the Wheat Belly bread recipes, it had a slightly bitter taste. Swerve is a commercial product that is useful for baking, a combination of erythritol and inulin.

Sucralose
Sucralose is manufactured from glucose by adding chlorine atoms. It has become the most popular artificial sweetener in the world, known to most Americans as Splenda.

Sucralose is very baking compatible, not changing in taste or texture with baking. The various forms of sucralose are usually combined with maltodextrin, such as in Granulated Splenda, and therefore pose some of the concerns listed above, including occasional abdominal complaints like bloating and gas and potential carbohydrate exposure of 0.5 grams carbohydrate per level teaspoon or 24 grams per cup, yielding up to 96 calories per cup. Carbohydrate content is therefore a potential issue only when large quantities are used. Like stevia, sucralose is also available as a liquid without maltodextrin.

Although sucralose has proven safe in worldwide consumption, there have been scattered reports of potential adverse effects. There’s the theoretical effect from the chlorine molecules contained within the sucralose molecule (since sucralose is glucose with added chlorine atoms, just as table salt is a sodium atom with a chlorine atom). However, there is no formal evidence that this has resulted in undesirable human effects. Limited animal evidence suggests alteration of bowel microorganisms; this has not been reproduced in humans.

Sweeteners to not use
Then there are the sweeteners that truly do have problems outside of potential appetite/insulin triggering. The sweeteners to avoid include sugar alcohols sorbitol, maltitol, and mannitol; they cause vigorous rises in blood sugar and provocation of small LDL particles, not to mention gas and diarrhea (unless, of course, you are not fond of your mother-in-law and would like to be entertained one evening). Avoid fructose sources, especially agave nectar, followed by maple syrup (real or high-fructose corn syrup-based), honey, and, of course, high-fructose corn syrup. (Yes, while honey has some good things in it, it is too rich in fructose. If you insist on using it, use the darkest honeys and use sparingly.) Beware of the “natural” sugars that are increasingly appearing on the market made from coconut and other plants; they are usually just sucrose or fructose.