Our addiction to sweet tastes has opened a Pandora’s box of commercial sweeteners, with the food industry advertising many as “natural.” One category is sugar alcohols, including the increasingly common xylitol. But are these sweeteners really natural, and are they safe? Or are they just another of industry’s attempts to snooker us into buying the newest fake-food without any health benefits — and perhaps a boatload of potential risks?
Being the new kids on the block, the data is just starting to come in on sugar alcohols. They owe their rising popularity to the public’s increased awareness about the risks of artificial sweeteners, such as saccharin and aspartame, which, as noted elsewhere, can cause the very health issues they claim to prevent.
The Rising Popularity of Xylitol and Sugar Alcohols
Sugar alcohols represent only about one percent of the total global sweetener market, but given current market trends, polyols are projected to be a $7.8 billion industry by 2022, thanks to the dental, pharmaceutical, personal care and food industries. Sorbitol leads the pack because so much is used in toothpaste and chewing gum. The next most common sugar alcohol is xylitol. (1)
Sugar alcohols, also called polyols, are neither sugars nor alcohols but rather carbohydrates with characteristics of both sugar and alcohol. They don’t contain the ethanol of alcoholic beverages. One of the touted benefits of these sweeteners is their lower glycemic index. Your body’s digestion of polyols is incomplete, so they contribute fewer calories than most sugars and therefore have a softer metabolic hit. Many are less sweet than sucrose (table sugar), however xylitol is about equal in sweetness. The major polyols, along with several common sugars and sweeteners, are listed below in order of glycemic index. The sugar alcohols are noted in bold. (2)
|Sweeteners and Glycemic Index|
|Stevia, Lo Han Guo 0|
|Yacon syrup, Erythritol, Inulin 1|
|Mannitol, Isomalt 2|
|Glycerol (glycerin) 5|
|Fructose, Galactose 25|
|Glucose, Dextrose 100|
Beyond the Glycemic Index: Problems with Sugar Alcohols
Sugar alcohols are often favored for their lower caloric load and lesser insulin-spiking tendencies, particularly by individuals struggling with weight and/or metabolic issues. However, there are several problems with the sugar alcohols that suggest they’re not what they’re advertised to be. Consider the following:
- Sugar alcohols are used primarily in processed foods, which are typically higher in calories and lower in nutrition overall. Just because a food contains xylitol does not necessarily mean it’s good for your waistline. Get in the habit of reading labels.
- Sugar alcohols contribute to a pervasive sweet flavor addiction, which compromises nutrition by steering us away from the diversity of foods and flavors we were designed to eat.
- The science behind some of the suggested health benefits of sugar alcohols is weak, at best.
- Sugar alcohols have their own curriculum vitae of adverse reactions.
- Sugar alcohols are anything but natural when you look at how they’re manufactured.
To be fair, some studies do support limited health benefits from sugar alcohols, although very few human studies have been performed. The following list highlights a few:
- Xylitol has been shown to produce fewer metabolic problems than sucrose in rat studies. (3, 4) Erythritol was shown to have no effect on serum glucose or insulin levels in one very small study involving five adult men. (5)
- Xylitol may have a favorable effect on bone health. (6)
- Xylitol may help prevent ear infections in children by reducing adhesion of bacteria, although research is inconclusive. (7)
- One rat study suggested xylitol may increase the rate of collagen synthesis in skin. (8)
- A few studies suggest xylitol or erythritol (9) may help prevent dental caries, but the latest scientific reviews cast doubt. Both the American Dental Association and the American Academy of Pediatric Dentistry have issued policy statements stating that the clinical evidence is unclear. (10, 11)
One of the downsides of the sweetener bandwagon is the prolongation of our massive reliance on sweet tasting foods, which works against a balanced diet. Foods should be enjoyable, but cravings are neither natural nor health promoting—especially sugar cravings.
Excess dietary sugar is carving years off people’s lifespan, and most of today’s packaged foods contain sugar in some form or another. Americans are consuming between 77 and 152 pounds of sugar every year—and that’s just table sugar and doesn’t include other refined carbohydrates. (12) The antidote to sweet addiction is the development of other tastes. You have sensors for sweet, salty, sour, and bitter, and the more you cut back on the sweet, the more you’ll develop the other three.
To some degree, sweet taste is acquired. Our bodies do not physiologically need anything sweeter than natural foods, such as whole fruit. Some of our preference for sweet tastes comes naturally. Human breast milk is actually quite sweet due to a special complement of sugars designed to feed the infant’s developing microbiome. The problem is, processed food manufacturers have capitalized on this by finding ways to make those foods even more appealing—even addictive—and the more of them we consume, the less sensitive and accepting our taste buds are to other flavors.
Sadly, this is even happening to infants whose mothers consume artificial sweeteners, which pass right into their breast milk (13). These babies are being conditioned from an early age to prefer intensely sweet flavors over all others. (14)
Research has raised concerns that artificial sweeteners may actually promote adipogenesis and weight gain. (15) Why? Scientists have discovered we don’t just have sweet taste receptors in our mouths—we have them in our gut, pancreas, bladder, brain, bone and many other tissues of the body, including adipose tissue. Science suggests high intensity sweeteners may cause weight gain by directly stimulating the development of new fat cells. (16, 17) The Mayo Clinic warns that sugar alcohols can elevate your blood sugar. (18)
Is Xylitol Hazardous to Your Oral Health and Microbiome?
A while back, I was one of 3 individuals to interview over 30 natural health experts to gain their perspectives on toxicity and detox in a 7-day online event called The Detox Project. One interview in particular, hosted by my colleague Dr. Jay Davidson, prompted a deluge of questions about xylitol! Here it is:
This is a good place to start the discussion about the downsides of sugar alcohols. As was shared by Dr. Gerry Curatola, founder of Rejuvenation Dentistry and recognized nationally as one of America’s top holistic dentists, xylitol is very disruptive to your microbiome — starting with the microbiome in your mouth.
More than 700 different bacterial species call your mouth home. Your oral microbiome is a biofilm as unique as your fingerprint. In addition to protecting you from pathogens, these colonies help mineralize your teeth, bring oxygen and other nutrients to your gums, and help maintain proper oral pH. Nourishing these colonies is what Dr. Curatola calls “organic gardening of the mouth.”
Just like in your gut, normal bacteria become problematic when homeostasis is disrupted. When oral ecology falls out of balance from poor diet, excess sugar, detergent toothpastes, etc., plaque and gum disease are the result. Unfortunately, xylitol is present in more than 90 percent of “natural” toothpastes. Toothpastes were originally developed by soap companies, so they offer little biological benefit. Xylitol and other sugar alcohols have antibacterial effects, but this is not a good thing for cultivating a healthy oral ecosystem.
Even many natural compounds, such as certain essential oils, are not beneficial for a healthy microbiome. This is a discussion for another time, but suffice it to say that sugar alcohols have no place in oral care products. For more about oral care, check out Dr. Curatola’s book Mouth Body Connection.
Xylitol and an Angry Gut
The very thing that gives sugar alcohols their favorable metabolic impact is what causes them to be unfriendly to your gut: indigestibility. Xylitol and other polyols pass through your digestive tract largely undigested, so they become a source of gastric distress, gas, bloating, cramps and diarrhea.
Sugar alcohols ferment in your gut, so they may exacerbate yeast or bacterial overgrowth. Polyols are FODMAPs and as such, they can cause diarrhea by pulling excess water into your large intestine. Symptoms may be greater if you have digestive disorders such as SIBO (19), irritable bowel syndrome, Crohn’s disease, diverticulitis or similar. (20) Xylitol may also contribute to acid reflux. Therefore, if you have GERD ,you should avoid it. Children may be highly susceptible to adverse reactions because of their immature digestive systems.
Many of the adverse reactions of sugar alcohols are reportedly dose-related, with reactions abating after a month or two, as your body adapts. It is recommended to keep your xylitol dose under 40 or 50 grams per day to avoid problems. (21) The Academy of Nutrition and Dietetics reports doses greater than 50 grams per day of sorbitol or 20 grams per day of mannitol may cause diarrhea. (22) Erythritol appears to trigger fewer GI problems than the other sugar alcohols and is generally considered the “best” of the sugar alcohols. (More on Erythritol below.)
If you have pets, be extremely cautious about products containing xylitol as they are highly toxic to dogs and cats. It takes only a very small quantity to poison a pet. Xylitol can be an ingredient in peanut butter and other products that dog parents lovingly offer as treats.
Sugar Alcohols are Anything But Natural
Despite how the industry might spin it, sugar alcohols are not natural sugars—they are laboratory-concocted chemicals. Xylitol, for example, is commercially made by first extracting a plant compound called xylan from birch trees or corn cobs—but that’s where natural ends. According to Dr. Curatola, nearly 80 percent of the xylitol on the market is manufactured using GMO corn cobs.
The process of converting xylan into xylitol involves an industrial process called hydrogenation, which should send an alarm. You are probably already aware of the health dangers of other hydrogenated food products, namely hydrogenated oils. Hydrogenated oils are known contributors to type 2 diabetes, liver disease, depression, Alzheimer’s, cancer, and a whole spate of other health horrors.
Many of the other sugar alcohols (sorbitol, mannitol, maltitol, etc.) are manufactured by hydrogenating cornstarch. Isomalt and lactitol are created from sucrose and whey. (23) But, it gets worse: The hydrogenation process requires a catalyst, and what’s typically used is a heavy metal called Raney nickel (aka spongy nickel), a fine-grained solid composed mostly of nickel derived from a nickel-aluminum alloy. Nickel is riddled with toxicity and associated with asthma, dermatitis, kidney problems and cancer. (24)
So, whether you’re starting with birch bark or corn husks, the end products are anything but natural. While there’s a lot in the literature about hydrogenated oils — and not much at all about hydrogenated plant compounds or sugars — it’s worth remembering hydrogenated oils were used for decades before their health-damaging effects were made known.
What About Erythritol?
Erythritol is different in that it’s a byproduct of sugar metabolism. Erythritol occurs naturally in many things, including soy sauce and fermented beverages such as wine, beer and sake. Erythritol is commercially manufactured by fermenting cornstarch with yeast—typically genetically engineered yeast. (25) The fermented mixture is then heated (to kill off the yeast) and dried, leaving erythritol crystals which are then washed, re-dissolved, and chemically purified.
Bacteria in the human gut do not appear to ferment erythritol, so it tends to be better tolerated and is non-caloric and non-glycemic. 90% of erythritol is digested in your colon, and the other 10% is excreted unchanged in the urine. (26, 27) Oddly, erythritol is also described as a “palatable ingested insecticide,” which at this time does not appear to be toxic in humans. (28) However, headaches and allergic rash are reported side effects. (29)
Erythritol is up to 70% less sweet than sugar, so it is often combined with other sweeteners such as xylitol and stevia. The brand Truvia is a combination of erythritol and stevia. Another product called Lakanto combines erythritol with monk fruit (luo han guo). Monk fruit has been used as a sweetener for centuries but is relatively new in the American marketplace. Its extract is 300 to 400 times sweeter than can sugar, yet it is non-caloric and non-glycemic.
Although erythritol forms naturally in nature, commercial erythritol is nevertheless produced in a lab and often involves the use of genetically engineered yeast. It might have some benefits in small quantities, but I still believe you are better off minimizing your use of this and other sugar alcohols.
Is it Time to Divorce your Sweet Tooth?
The news you probably don’t want to hear is that there is no perfect sweetener. In fact, there’s a price to pay for all of them. Instead of “which sweetener to use,” the question should be: How do we get past our love affair with sweet foods? My answer is to slowly reduce all sweeteners from your diet, with the goal of eventually eliminating all of them, regardless of how “healthy” they appear to be. This is really the only way to reprogram your body’s physiological response to sweets, which is part physical and part emotional, and for most of us starts at a very early age.
Sweeteners fulfill sociological and cultural needs. They don’t fulfill nutritional needs!
As already discussed, part of reprogramming your “sweet tooth” is retraining your palate to enjoy other tastes. A good example is bitter. Bitter foods are some of the most health-promoting on the planet, but most find them objectionable and consume far too few. Bitters such as arugula, dandelion and orange peel trigger your pancreas to secrete digestive enzymes and your gallbladder to release bile, and bile is critical for proper fat digestion and detoxification. (30, 31)
Honey, agave, and many other sweeteners all essentially break down into glucose and fructose, bringing the same metabolic risks—and they may even result in greater consumption because they seem more “natural.”
If you take the leap and go “cold turkey,” eliminating all refined sugar from your diet, you may experience a one or two week “withdrawal” period. This is best managed by keeping your blood sugar steady with regular meals rich in healthy fats, protein, non-starchy veggies, and high-fiber carbohydrates, such as quinoa. By the end of about two weeks, you should feel much better and your sugar cravings will be significantly diminished, if not gone.
If you just can’t quite cut yourself off, then the herb stevia remains my favorite natural sweetener. If you want to use xylitol or other sugar alcohols, moderation is key—I’m talking about a small portion in a cup of coffee or tea, not an entire dessert made from it or you may be spending your night in the bathroom. Lakanto could be a decent option because the erythritol is combined with monk fruit. Small quantities of raw unfiltered honey or yacón syrup might provide some health benefits.
Just be judicious with ANY of these sweeteners, and whichever ones you choose, adhere to a few basic guidelines:
- “Pan metrion arison” ~ Moderation in all things; all in good measure. (Cleovoulos, Greek Poet, 6th Century BC).
- Choose sweeteners that have undergone as little processing as possible, as close to the earth as possible. Try sweetening foods with real foods such as dates or bananas.
- Look for xylitol derived from birch bark, instead of corn stalks or corn starch (never mind GMO corn). Some organic producers will emphasize on their labelling their sources of xylitol and even methods of processing.
- Many commercial sweeteners have chemical compounds added, such as sodium benzoate, potassium sorbate, malic acid, and so-called natural flavors (which are not natural). Read those labels!
- Expand your palate, and help your children to expand theirs. Try foods unsweetened—and try new foods. Broadening your dietary horizons will not only add spice to your life but will improve your nutritional status as well. Do a bit of hunting and gathering the next time you visit the farmers’ market.