Sorbitol is a sugar alcohol with some helpful characteristics—but it can make some people distinctly unwell. It’s easily digestible for most people because they have the right microbes to break it down. Others, however, can suffer each time they eat foods that contain sorbitol.
Found naturally in some foods, especially stone fruits such as peaches and avocados, sorbitol is also synthesized and added to food and dental products for sweetness. It’s a polyol—the “P” in FODMAP, which stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.
FODMAPS are short-chain carbohydrates that occasionally cause gut trouble—gas, bloating, and diarrhea—especially when ingested in larger amounts.
A new study published on Feb. 15 in the journal Cell points to missing microbes as the likely reason for some people’s sorbitol intolerance. In order to test the underlying mechanism, they put mice on antibiotics and a high-fat diet. That caused a dramatic reduction in Clostridia gut microbes—bacteria that are normally abundant in infants and adults and are capable of breaking down sorbitol.
Microbes As the Missing Link
Previously, it was thought that poor absorption was the cause of sorbitol intolerance. The authors of the study pointed out that antibiotic use and high fat intake are also known risk factors involved in inflammatory bowel disease (IBD).
Other evidence, they wrote, that supports the argument that microbes are the true cause of sorbitol intolerance includes:
- Studies showing that IBD sufferers have a low abundance of the bacteria
- Higher rates of IBD in Western countries where antibiotic use and high fat intake are also higher
- Research showing an association between polyol intake and gastrointestinal symptoms in patients with IBD
“This discovery is crucial, given the prevalent use of sorbitol and similar sugar alcohols in the production of keto-friendly diet foods that are high in fat content,” Jee-Yon Lee, first author of the study and assistant project scientist at the University of California, said in a statement.
Sorbitol Popularity Soars
Synthetic sorbitol is derived from corn starch. Unlike high-fructose corn syrup, it’s a low-glycemic alternative that doesn’t cause a spike in insulin levels, which can ultimately lead to insulin resistance and Type 2 diabetes.
Sorbitol is a popular additive to foods deemed acceptable for ketogenic diets, which keep carbohydrate consumption at low levels. Sixty percent sweeter than sugar with one-third the calories, sorbitol also has properties that help preserve food and improve the texture.
Dr. Mark Burhenne, functional dentist and host of the podcast “Ask the Dentist,” noted that as the industry moves away from sugar, it will continue to use replacements such as sorbitol.
In 2021, sorbitol sales were $1.51 billion with an expected annual growth rate of 6.67 percent through 2030, when it’s expected to reach $2.7 billion, according to Straits Research.
Its report on the sorbitol market states: “Since too much sorbitol is known to cause gastrointestinal discomfort, it may have a diuretic effect, which might hurt sales growth. However, its benefits for blood sugar control and oral health exceed its drawbacks.”
Dr. Burhenne said it’s short-minded to believe the product is inherently bad—even though it’s made from corn, which he doesn’t like. However, there are non-GMO synthetic versions that offer cleaner options.
“For those who can’t digest it, there will be an issue,” he said. “Because we take a lot of antibiotics, because we are dysbiotic in our guts, because of the [processed] foods we eat, it allows certain bugs to become dominant.”
Dysbiosis Drives Dysfunction
Dysbiosis means that the balance of microbes is unfavorable and may cause any number of symptoms. Disease-causing bugs lurk in most microbial communities and can become dominant if beneficial microbes become too few. This is especially true when we expose our microbiome to a growing list of foods, medications, chemicals, and behaviors that wipe out large amounts of gut microbes.
Dr. Burhenne—who recently helped develop a toothpaste aimed at feeding good bacteria—has been speaking out on dental products that can kill protective microbes and lead to infection and disease.
Without a robust community of “good” bugs, we can become intolerant to sorbitol and other foods, said Cari Riker, registered dietitian and certified diabetes educator with Riker Nutrition Consulting.
Ms. Riker has worked with clients who are unable to digest sorbitol after experiencing just one of the problems raised in the study: either using antibiotics or eating a ketogenic diet. She prefers using a low-FODMAP diet to identify foods that are causing digestive problems.
Ms. Riker said food logs are best for revealing issues—mostly because serving sizes and the source of sorbitol both play roles in symptom severity. Testing may identify sorbitol as a problematic food, but it doesn’t reveal these subtle nuances.
“It’s confusing because a lot of times it’s foods that are healthy for them,” she said of food tests. “Everybody is so individual on what their health conditions are and what they are triggered by, like stress. Intolerances can get better, or they can get worse.”
3-Day Challenge
The best way to know is to remove all FODMAPS from the diet for two to six weeks and then add them back slowly. Ms. Riker then does a three-day challenge, increasing the serving size each day. For instance, she’ll have clients eat a quarter of an avocado on the first day, half an avocado on the second day, and three-fourths on the third day.
If at any point they experience painful changes in bowel movements or have other uncomfortable symptoms, they stop the challenge. “If they pass all three days, we know sorbitol is not an issue for them,” Ms. Riker said.
In the process, they may determine whether smaller servings are tolerable. Additionally, she might be able to help bring the gut back into balance using a specific probiotic—especially if they are using an antibiotic. Digestive enzymes might also help them tolerate certain foods.
Pharmaceutical Possibility
In the sorbitol study, researchers experimented with restoring the gut bacteria in the mice to see if they could resume digestion of the sugar alcohol. They noted, though, that mice have a higher tolerance for sorbitol than humans.
Researchers fed the mice a specific gut bacterium that produces butyrate, a short-chain fatty acid made in the gut that allowed Clostridia levels to return to normal. Researchers also suggested that mesalazine—a drug used to treat IBD—might be useful for those with sorbitol intolerance as it functions similarly to butyrate-producing bacteria.
Dr. Burhenne said the idea of using a drug for a single food intolerance is “terrible” and wouldn’t address the root cause. It could also bring unwanted side effects.
“To take a drug to fix flatulence … that’s not the way you should go with these things. That just treats symptoms,” he said, noting that it’s a common move made by pharmaceutical companies to make more money on an existing drug.
Sorbitol: Gut Wake-Up Call
Dr. Burhenne said a better approach for someone with sorbitol intolerance is to try different sugar alcohols because there’s likely one that he or she can tolerate. Others are xylitol and erythritol, for example.
“You probably have a bacteria in your gut that can deal with it. And if not, then it’s a wonderful way of knowing you don’t have a good gut. You have a dysbiotic gut,” he said.
Sweeteners such as monk fruit or allulose are less likely to cause gut symptoms, according to Dr. Burhenne. He said those options can help you sweeten food while correcting dysbiosis, which can serve as an opportunity to improve your health beyond digestion. Dysbiosis has been linked to brain disorders and other autoimmune conditions.