Long-term overconsumption of sugar has been connected with nearly every negative health outcome imaginable. Obesity, heart disease, high blood pressure, depression, skin damage, tooth decay, diabetes, fatty liver—if you want to avoid it, there's a good chance eating too much sugar can cause it. But humans love sweet things, so there's been a scramble to offer sugar alternatives that don't have the same harmful effects as actual sugar.
One popular category of sugar alternatives? Sugar alcohols. These go by names like sorbitol, erythritol and mannitol, and they're commonly used by food manufacturers who want to offer sweet-tasting products without scaring off health-conscious consumers with massive sugar and carb totals. But are sugar alcohols really a safer alternative? STACK investigates.
The Secret Behind Sugar-Free Products
First things first: Sugar alcohol is not a form of booze. That's because it does not contain ethanol, the key component of alcoholic beverages. Rather, sugar alcohols are derived from putting the natural carbohydrates that exist in plant products (such as fruits and berries) through a chemical process. The result is a white, water-soluble solid that can be used as a sweetener or a thickening agent.
Most sugar alcohols contain between 1.5 and 3 calories per gram, significantly less than table sugar's 4 calories per gram. If you see a product that would typically contain sugar being marketed as "sugar-free," odds are it contains one or more types of sugar alcohol. Sugar-free candy, cough drops, gum, chocolate, jams, jellies, baked goods—most contain sugar alcohol. Many nutrition bars and supplements use sugar alcohol to make their products more palatable without skyrocketing the carb or sugar count. Since sugar alcohols go by some pretty bizarre names, many people don't even notice them on an ingredients list.
Besides the low calorie count of sugar alcohol, their other selling point is that the human body cannot fully digest them. Why is that a benefit? Because it means that sugar alcohol—unlike table sugar—doesn't typically cause a rapid spike in blood sugar. Sugar's dramatic effect on blood sugar is a key reason why it's so harmful to the human body, since rapid changes in blood sugar have been closely tied to obesity, diabetes and high blood pressure. Sugar alcohols do contain carbs, so they do affect blood sugar, but since they are lower in carbs than real sugar and the body doesn't fully absorb them, the effects are not as dramatic. "Because your body doesn't completely absorb sugar alcohols, their effect on blood sugar is less than that of other sugars," writes the Mayo Clinic. This is why most products labeled as "diabetic-friendly" typically include sugar alcohols.
Additionally, sugar alcohols do not cause tooth decay. In fact, there's reason to believe they actively prevent tooth decay. According to the California Dentists Association, xylitol (a popular sugar alcohol) "inhibits the growth of the bacteria that cause cavities." This is why sugar alcohols are frequently included in toothpaste and mouthwashes.
Though research on sugar alcohols is still somewhat sparse, they look like a pretty awesome substitute for real sugar. They're lower in calories, they don't wreak havoc on your blood sugar and they don't contribute to tooth decay. However, sugar alcohols can bring about one rather infamous side effect.
The Laxative Effect
In the words of the Mayo Clinic, "when eaten in large amounts, usually more than 50 grams, but sometimes as little as 10 grams, sugar alcohols can have a laxative effect, causing bloating, intestinal gas and diarrhea." For a reference point, a serving of sugar-free Jolly Ranchers contain 15 grams of sugar alcohol.
I know what you're thinking. Yes, diarrhea and stomach discomfort are symptoms that seem to appear on every list of potential side effects in the known universe—more as a disclaimer than anything else—but sugar alcohols seem to be an exception. For certain people, the ingesting significant amounts of sugar alcohol leads to some horrifying gastrointestinal issues.
The laxative effects of sugar alcohol can be so significant, it has become ingrained in internet folklore. The Amazon.com reviews for the "Haribo Sugar Free Gummy Bears 5LB Bag" are equal parts terrifying and wildly entertaining. Countless customers recount their experience with this unpleasant side effect. Entire articles have been devoted to these reviews, which are so explicit and descriptive that it can be hard to tell where reality ends and fiction begins. Some excerpts from the actual reviews:
- "What came out of me felt like someone tried to funnel Niagara Falls through a coffee straw"
- "Streams of fire burst from my colon"
- "Guttural pronouncement so loud it threatened to drown out my own voice"
- "Don't eat more than 15 in a sitting unless you're trying to power wash your intestines"
- "Gastrointestinal armageddon"
There are currently 948 reviews on the product, and they are filled with stuff like that. Obviously, some are exaggerated fabrications, but they were posted after real people had real issues that were significant enough to leave a review warning others. River Donaghey, an associate editor at VICE, actually ate the gummy bears himself to see if the laxative effect was pure urban legend. He quickly found out it was no joke (article contains explicit language).
The ingredient in the product that's believed to cause this effect is lycasin, a hydrogenated syrup that consists mainly of the sugar alcohol malitol. The majority of sugar-free products won't cause this extreme degree of gastrointestinal chaos, but it is a very real side effect and something that should be monitored. Certain sugar-free products even bear an explicit warning on their label that reads: "excess consumption may have a laxative effect."
Perhaps the reason sugar-free candies seem to cause this effect more than other products is that they make the most extensive use of sugar alcohols. People expect candy to be really sweet, so sugar-free varieties need to include a significant amount of sugar alcohol to achieve the desired taste.
But why do sugar alcohols cause this problem in the first place? It has to do with the fact that our bodies cannot fully digest them. Instead, they're fermented by the bacteria in our large intestine. According to The International Food Information Council Foundation, this can lead to "abdominal gas and discomfort in some individuals." They also warn that "total daily consumption should be considered since it is the total intake that may primarily drive GI disturbance or laxative effects." Products that make significant use of sugar alcohols must list the amount in their nutritional facts, so it is easy to track how much you're ingesting.
But again, some people seem to handle them just fine while others do not. Avoiding overconsumption of products high in sugar alcohol is a good way to avoid these nasty side effects, but the only way to truly learn your limit is through personal experience.
Besides the potential for temporary gastrointestinal discomfort, sugar alcohols are a pretty strong alternative to real sugar. They won't rot your teeth out, they're lower in calories and carbs, they don't cause dramatic shifts in blood sugar and the existing research shows few long-term health risks.
However, if you consume a large amount of sugar alcohol on a daily basis, you might want to re-examine your diet. Why? Because sugar alcohols are used almost exclusively in ultra-processed foods. According to Yale-New Haven Hospital, "sugar alcohols are not commonly used in home food preparation, but are found in many processed foods."
The average American gets nearly 60 percent of his or her calories from ultra-processed foods, but such products are rarely healthy choices. "Highly processed foods typically have fewer vitamins, minerals, phytochemicals, antioxidants and nutrients like fiber and protein than lower processed foods. They also usually contain more low-quality fat, sugar, sodium, calories and refined carbohydrates," says Brian St. Pierre, nutrition coach at Precision Nutrition. Sugar alcohol itself might be a healthier alternative than real sugar, but what's coming along for the ride is likely lacking.
Over time, consuming products high in sugar alcohol could alter your tastebuds and lead to intense, constant cravings for sweet products. This could lead to a natural gravitation towards ultra-processed products, since natural and low-processed offerings rarely possess the same level of sweetness.
Products made with sugar alcohols are certainly OK as an occasional snack, but they shouldn't become a foundation of your diet.
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