Why Sugar Alcohols Cause Digestive Problems
As the epidemic of obesity, diabetes and other diseases of excess sugar consumption has taken its toll, consumers have looked for ways to lower their calorie intake. Food manufacturers have taken notice and many have turned to alternative sweeteners for their products.
Sugar alcohols, like sorbitol, maltitol, xylitol and erythritol, emerged with the promise of lower calories and less negative effects on blood glucose and weight gain than regular sugar or high fructose corn syrup.
Unfortunately, all but one of these sugar alcohols are known laxatives and can cause significant gastrointestinal side effects, like bloating, abdominal cramps, stomach rumbling, excessive flatulence and even diarrhea at high enough doses.
What are Sugar Alcohols?
Despite their name, sugar alcohols do not contain ethanol and are not alcoholic. They are also known as polyols or scientifically as polyhydric alcohols.
While some sugar alcohols like sorbitol, mannitol and xylitol do occur naturally, they are usually produced commercially by the hydrogenation of sugar or corn syrup using a nickel catalyst.
Sugar alcohols are generally less sweet than regular table sugar, with lactitol and isomalt having only 40% and 50% of the sweetness of sugar respectively. Sorbitol is listed as 60% as sweet as sugar, erythritol 80% and maltitol 90%, with only xylitol considered equally as sweet as sugar.
Polyols also have varying degrees of effects on blood sugar, with erythritol and isomalt having a very low glycemic index of 0 and 2 respectively, sorbitol with a GI of 9, xylitol at 12 and maltitol syrup right up at a significantly high glycemic index of 52.
Compared to consuming sugar, some of these products may have benefits in small amounts for diabetics and those trying to cut down their sugar intake and lose weight.
However, many people find consuming foods and other products with sugar alcohols can easily lead to painful gastrointestinal side effects. Let’s look at why this happens and the worst sugar alcohols for diarrhea and other digestive problems.
Also ahead, the one sugar alcohol that doesn’t cause stomach upsets and intestinal pain and an even better, sweeter and cheaper alternative to sugar alcohols.
Sugar Alcohol Side Effects
When you eat a food with sugar alcohols they pass through your small intestine only partial absorbed. This is because the human digestive system has trouble break down their structure.
As they reach your large intestine, the molecules of most sugar alcohols tend to pull water into the gut by osmosis. This often leads to watery stools and, in large amounts, full blown diarrhea.
Even in smaller doses, polyols like mannitol, sorbitol, lactitol and maltitol need to be broken down by bacterial fermentation in your colon.
This process creates a lot of flatus gas and, as these gases get trapped within your intestines, they can result in belly bloating, painful cramps, abdominal discomfort and finally lots of flatulence on the way out.
The 6 Worst Sugar Alcohols for Diarrhea, Bloating and Gas
Made by hydrogenation of sugars, usually from corn syrup, mannitol is considered the worst sugar alcohol for causing diarrhea, intestinal cramps, belly bloat and excessive flatulence.
The FDA requires a warning label on products that contain large amounts of mannitol that they have a laxative effect. Mannitol is also recommended medically for bowel distention before an examination.
It’s hardly surprising then that mannitol causes diarrhea, painful cramps and many other forms of gastrointestinal distress. Clearly this polyol has a powerful and usually unwanted effect on your lower intestine.
Anyone suffering from digestive problems, and particularly individuals with irritable bowel syndrome or sensitivity to FODMAPs should definitely avoid mannitol.
Where Is Mannitol Found?
Due to its strong laxative effect, mannitol has fallen out of favor as a food additive in recent years. However, it is still commonly used as a coating agent in ice cream and confectionary, as a dusting powder on chewing gum and, bizarrely, in pharmaceutical tablets used to treat health conditions.
People with IBS or other gastrointestinal disorders should watch out for and avoid any foods or products with the E number E421 for mannitol on the label.
Mannitol also occurs naturally in fairly high levels in certain fruits and vegetables, like watermelon, peaches, cauliflower, butternut squash, sweet potatoes, celery, snow peas and button mushrooms.
If you experience bloating, excessive flatulence or diarrhea after eating large amounts of one of these gassy vegetables or fruits then mannitol is the likely culprit.
Unlike mannitol, food manufacturers use sorbitol extensively as a sugar substitute in processed foods. They even promote it as healthy and diabetic friendly for its lower glycemic index and calories than sugar.
However, while it’s not quite as bad at mannitol at causing intestinal discomfort and excessive gas, sorbitol is still a strong laxative and requires the same FDA warning. It is often even sold as a laxative in the drugstore.
Other side effects of sorbitol consumption include stomach cramping, heavy flatulence, tummy rumbling, abdominal pain and watery stools.
Some research is also showing that excess sorbitol in your body may contribute to advanced glycation end products, now thought to be one of the primary sources of aging within your body.
People with IBS, Crohn’s disease and other gastrointestinal disorders should avoid sorbitol. Though anyone concerned with better digestive health would likely benefit from less sorbitol in the diet, particularly in the concentrated form found in packaged foods.
Where Is Sorbitol Found?
The sugar alcohol sorbitol is most often found in chewing gum, jelly sweets, sugar-free jams and marmalade, many kinds of candies, ‘low sugar’ chocolates, wafers, cookies and ice cream. Bottled smoothies, sauces and even some breakfast cereals contain sorbitol.
It is also commonly found in toothpaste, as a coating for dried fruits, like sultanas and raisins, and in cake and pudding mixes. Commercial apple and pear juice and stone fruit juice, such as peach or plum, can be an especially high source of sorbitol as well.
Manufacturers often sneak sorbitol into their products hidden as E420 so keep an eye out for this additive E number on ingredient labels.
Some gas causing fruits also contain natural sorbitol, such as apples, pears and most stone fruit, like cherries, apricots and plums. Dried fruits like prunes are often a concentrated source of sorbitol too.
Similar to sorbitol, and often mixed with it in a variety of processed and packaged foods, maltitol is yet another one of the polyols created by hydrogenating corn syrup.
Like the previous two sugar alcohols, it also carries a laxative warning in many countries and will cause diarrhea, an upset stomach and other forms of gastrointestinal discomfort at high intakes and even low doses in sensitive individuals.
Maltitol has about half the calories of sugar and is indeed often sold as a powdered sugar substitute and marketed to people with diabetes or those wanting to lose weight.
Though to be honest, I really can’t understand why someone would risk their digestive health with a sugar alcohol like maltitol when healthy and supersweet stevia is available and even cheaper to buy.
Maltitol also has the highest glycemic index of any of the sugar alcohols, with a significant GI range of between 35 when powdered and as high as 52 for maltitol syrup, approaching that of table sugar at 60.
This makes the diabetic friendly and weight loss claims of maltitol promoters look very flimsy indeed. Even without the gastrointestinal issues of maltitol this polypol can barely be considered better than regular sugar from a health perspective.
Where Is Maltitol Found?
Many ‘sugar-free’, ‘low-calorie’ or ‘no added sugar’ products use maltitol, like ‘diet’ muesli bars, candies, chocolates and baked products.
Like sorbitol, maltitol is heavily used in chewing gum and dairy-based desserts like ice cream. It is also a common ingredient in cream fillings and frostings, as well as cookies and cakes.
Look out for maltitol as E695 on product labeling. If you’ve been suffering from unexplained diarrhea, a bloated belly or just more gas than usual, then check the ingredients list of what you have recently eaten for maltitol or E695.
Isomalt is made by enzymatically rearranging sucrose into isomaltulose and then hydrogenating it with a nickel catalyst. This strange laboratory creation is 50% glucose, 25% sorbitol and 25% mannitol after hydrolysis.
Being malabsorbed in the small intestine, isomalt is likely to provoke stomach pain, intestinal discomfort and bloating, excessive farts and diarrhea when it arrives in your large intestine if consumed in amounts higher than your individual tolerance.
Medical resources list 20 grams a day as a level at which isomalt can produce gastrointestinal distress, though many people find they have negative side effects from this polyol at much lower levels.
Like other sugar alcohols, anyone suffering from irritable bowel syndrome, FODMAPs sensitivities, or even just regular bloating and bad gas should completely avoid isomalt.
Where Is Isomalt Found?
Because it doesn’t crystallize as easily as corn syrup or sugar, manufacturers use isomalt in hard-boiled candy like lollipops and toffees, as well as many other ‘low-calorie’ or ‘diet’ sweets.
Fudges, cakes and wafer biscuits often contain isomalt and some cough medicine and throat lozenges are another hidden source.
Commonly used as a glazing agent, isomalt will be listed as E953 on product packaging so keep an eye out for this number and limit your consumption wherever possible.
Yet another engineered sugar alcohol, this time produced from the milk sugar lactose, lactitol has around 40% of the sweetness of table sugar. Though due to its heat stability in the chance to print ‘sugar-free’ on labeling, food manufacturers use lactitol extensively in the products.
This is despite the fact that lactitol is well known to cause diarrhea in doses as low as 20 grams. Lactitol is even sold in the drugstore as a laxative for constipation.
Lactitol is indigestible in the small intestine and arrives largely intact in the large intestine. When consumed in large amounts this causes passive diffusion in the bowel, resulting in watery stools.
Even in smaller amounts, lactitol is fermented by colonic bacteria, leading to a rumbling belly, abdominal bloating, intestinal cramps and usually a lot of farting.
Where Is Lactitol Found?
Hiding on food labels as E966, lactitol is often used in ice cream, cookies, chocolates and candies, particularly if they’re labeled ‘diet’ or ‘reduced calories’.
Baked goods, processed meals and chewing gum are other sources of lactitol and, for some reason, it is also regularly added to prescription medicines.
Often marketed as a healthier sugar alcohol, xylitol is a polyol produced from fermentation of wood or agricultural waste.
Studies have shown it beneficial for diabetes, weight management and preventing tooth decay, though this is hardly surprising given it was used in these studies to replace sugar.
Healthy stevia is also very beneficial in these areas, has no calories, and, unlike xylitol, doesn’t cause gastrointestinal distress at high doses.
While not considered as bad for bloating, flatulence and diarrhea as mannitol, maltitol or sorbitol, xylitol is still a problematic sugar alcohol for some people, causing an upset stomach, intestinal pain and watery stools at high doses.
Dog owners should also be aware that xylitol is highly toxic to dogs. Given the way sugar alcohols are often combined in ‘sugar-free’ and ‘low-calorie’ products, it’s best to avoid giving your dog any ‘diet’ products that may have xylitol in it.
Where Is Xylitol Found?
Xylitol has E697 as the number to watch out for on low-calorie products. It is regularly found in chewing gum, hard candies, gum sweets, breath mints, jams and jellies.
It often sweetens toothpastes and mouthwashes but here it is usually not ingested. However, xylitol can be particularly problematic when added to liquids like cough syrup and diet sodas, as shown in this research.
Xylitol is also packaged and sold as a sugar substitute, but abdominal bloating, excessive gas and loose stools are potential side effects of using this product.
Children seem to be more sensitive to xylitol than adults, even taking into account their smaller body weight, and doses of 20 grams daily are known to cause gastrointestinal distress.
The 1 Sugar Alcohol That Doesn’t Cause Digestive Problems
Unlike the other sugar alcohols listed above, erythritol does not usually cause diarrhea, excessive gas or other forms of intestinal discomfort for most people, unless at very high doses beyond which would usually be consumed in food.
This is due to the way its smaller structure is absorbed in the intestinal tract and excreted in urine. Preliminary animal studies also seem to indicate that erythritol doesn’t damage kidneys either.
Erythritol has about 60 to 70% of the sweetness of sugar, yet has no effect on blood sugar so is considered a good sweetener for diabetics. If nothing else, erythritol certainly appears to be a safer sugar alcohol than mannitol, sorbitol, maltitol, isomalt, xylitol and lactitol.
Where Is Erythritol Found?
Listed as E968 on product labels, erythritol is used in low-calorie beverages and ‘diet’ dairy foods like yogurt, custard and ice cream. Chewing gum, lozenges, chocolate, candies and other confectionery are sometimes made with erythritol as well.
It is also sold directly as a table sugar replacement. For diabetics or people looking to lose weight, this granulated erythritol available at Amazon could be a good option. Reviewers certainly seem to like the taste of it.
Can Sugar Alcohols Damage Your Gut Lining and Feed Bad Bacteria?
Some health experts believe regular consumption of sugar alcohols may damage the lining of your gut with they way they increase intestinal osmotic load and their heavy fermentation in the lower intestine.
This research on sugar alcohols and IBS concluded “Further research is needed
to understand the effects of specific polyols on gastrointestinal function, sensation, microbiome, and metabolome…”.
In other words, scientists aren’t really sure just what the long term effects of sugar alcohol consumption is on gut health and whether they can promote or worsen intestinal disorders.
What is clear is that with the exception of erythritol, sugar alcohols arrive partially undigested in the colon and proceed to draw water into your bowel through the process of passive diffusion.
Bacterial breakdown then begins in earnest and polyols like sorbitol, maltitol and lactitol may feed bad bacteria and other pathogens in your lower intestine if they are predominant there.
When the less beneficial strains of bacteria in your colon gain the ascendancy they can promote many digestive problems like gastroenteritis, IBS, Crohn’s Disease, small intestine bacterial overgrowth, leaky gut syndrome which can lead to serious autoimmune diseases.
Are Sugar Alcohols Healthy or Unhealthy?
While food manufacturers like to promote polyols as healthy, sometimes even going as far as describing them as prebiotics, there is little evidence to compare them to the benefits of inulin or other recognized prebiotics, and even these products can cause gastrointestinal upsets in large doses.
With how easy it is to experience the side effects of sugar alcohols, like stomach pain, belly bloating, abdominal cramping, excessive gas and diarrhea, it’s quite a stretch to describe isomalt, mannitol or even xylitol as healthy.
Most protocols for gut healing and better digestive health, such as the GAPS diet and specific carbohydrate diet (SCD), strongly advise people to completely avoid sugar alcohols.
Doctors also instruct people with IBS, Crohn’s disease, ulcerative colitis and other gastrointestinal disorders to keep well away from polyols. Perhaps it would be best to take this advice as a preventative strategy before these problems ever develop.
There isn’t a great deal of evidence that sugar alcohols are definitely unhealthy, aside from the way they promote gastrointestinal distress. However, unless taken as a direct one for one replacement for damaging sugar, there also isn’t much of a case for polyols being healthy either.
A Better Alternative to Sugar Alcohols
Sugar alcohols are being added to an increasing number of processed foods these days. If you’re not careful to limit them in your diet you can easily find them causing symptoms like bloating, bad gas, intestinal pain and even diarrhea.
While the majority of people can handle small amounts of them, it’s best to check product labeling and avoid mannitol, sorbitol, maltitol, isomalt, lactitol and xylitol wherever you can.
This liquid stevia I use in my kitchen is a much healthier choice than sugar alcohols for sweetening food and drinks. It is around 200 times sweeter than table sugar and you only need a drop or two to sweeten beverages or mixed into food.
If this isn’t suitable for your purposes consider this very low calorie granulated erythritol, the only sugar alcohol unlikely to cause digestive upsets and diarrhea.
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