Artificial Sweeteners Redux – The Sugar Alcohols
I previously covered the major artificial sweeteners used as sugar replacements by consumers – aspartame, sucralose, and saccharin. A second category of artificial sweetener, the sugar alcohol, is frequently used in products ranging from medical compounds to sugar free gum. Sugar alcohols include mannitol, sorbitol, xylitol, glycol, and methanol (there are many others – these are just the common ones) and are generally less sweet than traditional sucrose (with some exceptions). Sugar alcohols do not have the same baking or cooking properties as sugar, and as such are not commonly used in prepared foods.
Xylitol is the one sugar alcohol with a sweetness similar to sucrose, and is used frequently in sugar free gums (a misnomer – they have sugar alcohols, and are not completely calorie free either – xylitol has approximately 40% of the calories of sugar). ) It is derived naturally from the birch tree (the name is derived from the Greek word for wood), and is also used in many sugar free hard candy products. Xylitol is popular in the dental crowd in that it can reduce calories up to 85% when chewed regularly.(1) Xylitol has also been shown to reduce inner ear infections (due to both the chewing action and anti-microbial properties effecting the Eustachian tubes).(2)
Sorbitol is similarly used in sugar free gums and candies, though it is slightly less sweet than Xylitol. It is frequently added to diet sodas and ice creams, and used in industrial processes ranging from cosmetic production to model rocket fuel composition. Medically, sorbitol has been used as a cost effective laxative product.(3) Similar to xylitol, sorbitol is naturally derived from stone fruits. Most commonly associated with sorbitol are prunes (hence the laxative effects of prune juice).
Mannitol is an isomer of sorbitol and is found in most plants (though it can be industrially created as well). Like sorbitol and xylitol, it is used in chewing gums and other products needing a low calorie sweetener. Mannitol has multiple medical uses also – ranging from the delivery of drugs to the brain due to its facilitation of crossing the blood-brain barrier (4) to oliguric renal failure, though large doses of mannitol can actually cause renal failure through a different mechanism (5). Mannitol was originally one of the popular colonoscopy preps, until it was found to contribute to exploding bowels.(6)
Glycol is frequently associated with ethylene glycol, diethylene glycol, and polyethylene glycol. All three are chemically related and have a sweet taste, but have very different uses and are not metabolized by the body in the same way. You will often find bad science in alarmist literature ignorantly comparing the different compounds inappropriately in an alarmist manner that associates brake fluid with medical use.(7) Chemistry doesn’t work that way, fortunately – not only are different chemical compositions metabolized differently, even if they “appear” to be similar, they break down completely differently. A great example is sodium ferrocyanide – an anticaking additive to table salt. It’s precursor ligand, cyanide, is highly toxic, but is bound to a metal (iron in this case) and the chemical bonds are not brokwn down by the body in normal circumstances. As such, sodium ferrocyanide is not particularly toxic in small doses (anything, including water, can be considered toxic in high doses).(8)
Ethylene Glycol is primarily used as antifreeze, and is highly toxic. Diethylene glycol is used as an industrial solvent (and is part of many brake fluids). Diethylene glycol (DEG) has been associated with numerous cases of poisoning and is the subject of multiple “adding antifreeze to wine” scandals – technically it is more often DEG than ethylene glycol that has been added(9). Polyethylene glycol, or PEG, is the most known to those with IBD. It is the base of the currently used laxatives in colonoscopy preparation, including GoLYTELY™, Dulcolax™ and MoviPrep™.
Sugar alcohols are very popular amongst diabetics because they are not broken down completely in the intestines and don’t result in the absorption of glucose to the same degree as traditional sugars. This lack of breakdown is what causes their other less friendly effects for those with IBS, Crohn’s Disease, and Ulcerative Colitis, namely diarrhea and bloating. Malabsorption depends partially on the genetics of the individual, with some individuals having difficulty when consuming as little as 5g, and just about all individuals having some GI difficulties at 20g.(10) As a point of reference, most sugar free gums have 1.25 – 2 grams of sugar alcohols. By contrast, a serving of sugar free Jelly Belly™ Jelly Beans, consisting of 35 beans, has 25g of sugar alcohol.(11) In addition to not being broken down fully, they can cause an increase in intestinal motility, something that is not generally welcome to those with IBD.(12) Diabetics with IBD will have to weigh the blood-sugar related benefits with the IBD-associated risks.
Although it is not directly IBD related, there is one other concern with pets and sugar alcohols. They can cause severe hypoglycemia and liver failure in very small doses – a pack of Trident™ or Extra™ gum is enough to be fatal for smaller dogs.(13) Additionally, pets like the sweet taste of antifreeze, which is similarly dangerous for them to consume. As such, sugar alcohol-containing products should ALWAYS be kept away from your pets.
· Xylitol, mannitol, sorbitol, and other alcohol sugars all have a laxative effect at high doses. They have all been used medically as laxatives at one point or another, with polyethylene glycol (PEG) being the current gold standard for colonoscopy prep.
· Sugar alcohols are popular additives to diet soda, sugar free gums, and sugar free candies.
· A stick of gum here or there won’t impact most people with IBD, but consuming even a moderate amount of sugar free candy can mean great intestinal distress.
· Sugarfree candies and gums should be kept in places where your pets can’t get at them.
1. Ly, Kiet A., Peter Milgrom, and Marilynn Rothen. "Xylitol, sweeteners, and dental caries." Pediatric dentistry 28, no. 2 (2006): 154-163.
2. Uhari, Matti, Tero Kontiokari, and Marjo Niemelä. "A novel use of xylitol sugar in preventing acute otitis media." Pediatrics 102, no. 4 (1998): 879-884.
3. Lederle, Frank A., David L. Busch, Kimberly M. Mattox, Melissa J. West, and Donna M. Aske. "Cost-effective treatment of constipation in the elderly: a randomized double-blind comparison of sorbitol and lactulose." The American journal of medicine 89, no. 5 (1990): 597-601.
4. Rapoport, Stanley I. "Osmotic opening of the blood–brain barrier: principles, mechanism, and therapeutic applications." Cellular and molecular neurobiology20, no. 2 (2000): 217-230.
5. Dormán, Henry R., James H. Sondheimer, and PHAVIT CADNAPAPHORNCHAI. "Mannitol-induced acute renal failure." Medicine 69, no. 3 (1990): 153-159.
6. La Brooy, SusanJ, C. L. Fendick, A. Avgerinos, C. B. Williams, and J. J. Misiewicz. "Potentially explosive colonic concentrations of hydrogen after bowel preparation with mannitol." The Lancet 317, no. 8221 (1981): 634-636.
10. Powell, Don W. "18 Approach to the patient with diarrhea." Clinical Gastroenterology (2008): 304.
12. Salminen, Eeva K., Seppo J. Salminen, Leena Porkka, Pete Kwasowski, Vincent Marks, and Pekka E. Koivistoinen. "Xylitol vs glucose: effect on the rate of gastric emptying and motilin, insulin, and gastric inhibitory polypeptide release." The American journal of clinical nutrition 49, no. 6 (1989): 1228-1232.
13. Dunayer, Eric K., and Sharon M. Gwaltney-Brant. "Acute hepatic failure and coagulopathy associated with xylitol ingestion in eight dogs." Journal of the American Veterinary Medical Association 229, no. 7 (2006): 1113-1117.