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Recent Research

I want to talk about the safety of sugar alcohols, particularly xylitol and erythritol. These sweeteners, once thought to be safe and even beneficial, have now been linked to an increased risk of cardiovascular disease.

While two studies published in prestigious journals are turning over the apple cart, many experts are challenging the results. This leaves us consumers with the question of whether xylitol, erythritol, and other sugar alcohols are actually safe to consume. Let’s dig in. 

A recent study published on June 6, 2024, in the European Heart Journal concluded that “xylitol is associated with an increased risk of a major adverse cardiovascular event. Moreover, xylitol both enhances platelet reactivity and thrombosis potential in vivo.” This means that they found xylitol-sweetened drinks triggered the platelets in the blood to clot faster than usual, leading to increased risk of a thrombosis, stroke, or cardiovascular event. 

A 2023 study published in Nature had a similar result regarding erythritol. Researchers found that consumption of erythritol also increased the clotting of the platelets, increasing the risk of a thrombosis, stroke, or cardiovascular event.

Before we further examine these studies, let’s step back and review what sugar alcohols are, and consider the benefits that got them into our foods and products in the first place.

What are Sugar Alcohols?

Sugar alcohols have found their way into a host of foods marketed as “heathy” low-sugar or no-sugar choices. The most popular are xylitol, sorbitol, and erythritol, but others, like mannitol, matitol, lactitol, and isomalt, are hidden on labels of many of your favorite health foods and products. They’re included in a wide range of products like ice creams, cookies, energy and protein bars, protein powders, toothpaste, gum, mouthwashes, and more.

Sugar alcohols are carbohydrates. Some of them, like sorbitol and erythritol, are derived from plants like fruits and vegetables. They are not zero-calorie sweeteners, as they do contain a few calories. They are generally 25x to 100x sweeter than table sugar. Chemically, they are a hybrid of a sugar and alcohol molecule. It’s critical to note that they do not raise blood sugar. They do not stimulate the pancreas to secrete insulin and they have little to no effect on blood glucose. 

Unlike sugar or alcohol on their own, these molecular structures do not break down in the stomach or small intestine, which is why they do not impact blood sugar. Instead, they travel to the large intestine, where they are mostly fermented by the gut bacteria. What is left over is absorbed by the liver and stored as glycogen.

So far, research suggests sugar alcohols do not negatively alter the gut microbiome like other artificial sweeteners (i.e. aspartame or sucralose) do. Studies have shown that they can, in fact, boost beneficial Bifidobacteria in the gut. In fact, most sugar alcohols are considered prebiotics because they are not digested until they reach the large intestines. The sugar alcohols isomalt and maltitol have been found to boost beneficial bacteria like Bifidobacteria, lactitol has been shown to protect the gut from harmful bacteria, and xylitol has been shown to increase beneficial bacteria such as Firmicutes and Prevotella.

Multiple studies have cited evidence supporting the use of sugar alcohols in the management of diabetes. They have been linked to improving metabolism, absorption, and the body’s control of glucose and insulin levels. The only caveat mentioned is the gas, bloating, and intestinal upset that often happens if they are consumed in excess.

See also 3 Prebiotics for Better Sleep, Digestion, and Immune Support

Are Sugar Alcohols Causing Your Digestive Distress?

You may have heard of the FODMAP Diet, a restrictive diet for folks with chronic digestive problems. Sugar alcohols are polyols, which represent the “P” in the FODMAP diet. FODMAP is an acronym for Fermentable Oligo-, Di-, Mono-saccharides and Polyols. These terms are the scientific names given to groups of carbohydrates that may cause digestive issues for some people.

Most people with healthy digestive systems can tolerate FODMAPs and sugar alcohols, but those with sensitive digestion may want to avoid this form of sweetener. With more and more food manufacturers using sugar alcohols to sweeten foods, many of us, in the pursuit of good health and a low-sugar diet, may end up experiencing gas, bloat, and other digestive concerns without realizing what may be causing it. 

FODMAPs, including sugar alcohol sweeteners, consist of short chains of sugars that are osmotically active: they pull water from the body into the intestines. This has been linked to bloating, gas, abdominal discomfort, and looser stools. 

Get to Know the Sugar Alcohols – They Are Not Created Equal

Xylitol

• Xylitol has 40% less calories than sugar.
• Xylitol has been well-studied because of its claim to fame for supporting dental health and protecting against dental cavities, which is why you see xylitol in gums, toothpastes, and mouthwashes.
• Most research suggests it is generally well-tolerated and has not been found to play a major role in digestive distress concerns. 
• NOTE: Xylitol is toxic to dogs. While humans do not absorb it into their small intestines, in dogs it is rapidly absorbed. This triggers a surge in insulin which can quickly and dangerously lower the dog’s blood sugar within 10-60 minutes.

Erythritol

• Erythritol has only 5% of the calories of sugar, but is 70% as sweet. 
• It does not have the same digestive distress potential as some other sugar alcohols because much of it is absorbed in the small intestine and then excreted in the urine without raising the blood sugar. 
• Erythritol is found in the sweetener Truvia. In fact, although Truvia is marketed as a stevia sweetener, it is mostly erythritol. 
• Erythritol is generally considered one of the healthiest sugar alcohols. It’s calorie-free, doesn’t raise blood sugar levels, is less likely to cause digestive upset than other sugar alcohols, and it won’t hurt your dog.

Sorbitol

• Sorbitol is about 60% as sweet as sugar with 60% of the calories. 
• It is commonly used in foods and soft drinks.
• If taken in excess, sorbitol has been studied to cause some digestive distress.

Maltitol

• Maltitol is 90% as sweet as sugar with about half the calories. 
• Maltitol is absorbed into the bloodstream and has the largest blood sugar spike of any of the sugar alcohols, so it’s best to avoid maltitol if you have blood sugar concerns. 

See also Can “Normal” Blood Sugar Levels Shrink Your Brain?

Do Xylitol and Erythritol Increase Risk of Cardiovascular Disease?

Let’s get back to those studies I mentioned earlier which suggested xylitol and erythritol cause platelet clotting. Even though they were published in separate journals, they were conducted by the same researchers. These were observational studies, with just eight human participants in one study and just ten in the other. It is well-accepted that observational studies do not identify causality; more specific targeted research with larger groups of participants are needed.

Quite a few scientists and doctors challenge the conclusions of these studies. My favorite and most eloquent dispute is one by Peter Attia, M.D. You can read his full review of both studies here. He discusses the many reasons why he and others believe this study is flawed.

While Dr. Attia’s review points out the many shortcomings of these studies, it does not explain why there were observational findings that linked these sugar alcohols to an increased risk of platelet aggregation of clotting. When it comes to xylitol, the body can produce its own supply beyond what is ingested. In both studies, exposure to dietary xylitol or erythritol were not taken into consideration–putting the source of the sugar alcohols into question. In addition, the clotting in both studies was measured more than 12 hours after ingesting the erythritol or xylitol drinks, even though they had concluded that these sugar alcohols are metabolized out of the body within 4-6 hours… so where did the measured sugar alcohols ultimately come from? This analysis suggests that there was possibly another unknown source of these sugar alcohols.

Conclusion: Too Good to be True?

Overall, sugar alcohols seem to be safe and even healthy in small amounts, but research is still scarce and it has only been a few years since these sweeteners have entered the mainstream. Many food additives initially branded as safe eventually get pulled off the market as more and more people consume them and more research is published.

If small amounts of these sweeteners will challenge those sensitive to FODMAPs, does that mean that average amounts will be safe for everyone? I think it is certainly still too early to tell. Remember these are highly processed, highly concentrated, and highly refined sweeteners. Before I would give the okay to regular or heavy use of these, I would wait for more research to come in.

In small amounts, xylitol is likely fine as chewing gum or in toothpaste to support healthy teeth and oral hygiene, especially because you are not swallowing it.

See also Podcast Episode 145: Reasons to Chew Mastic Gum with Logan Wright

Finally, I think the biggest takeaway here is that when it seems too good to be true, it probably is. I don’t think that sugar alcohols are a sweetener that is sustainable in the long term. We should be focusing on eating whole foods that I call recognizable food: ideally, you can look at your plate and recognize where everything came from in nature.  It’s always best to eat whole, organic, and non-processed options. While sugar alcohols may end up being safe and, as I cited, there is plenty of evidence suggesting they have healthy benefits, they are not whole, recognizable foods. In my opinion, they should be consumed in moderation if at all.