People with obesity or type 2 diabetes are often recommended these products as a “healthier choice,” but the data shows that’s not the case, says Stanley Hazen, M.D., a physician-scientist at the Cleveland Clinic in Ohio.
“The evidence suggests that people who are already at high risk of cardiovascular disease may be putting themselves at even greater risk by using these sugar substitutes,” Dr. Hazen said.
What is Xylitol?
Xylitol is a sugar alcohol and an approved alternative sweetener that’s one of many options for reducing added sugars in the diet, says Joan Slavin, PhD, a professor of food science and nutrition at the University of Minnesota in St. Paul, who was not involved in the study. Although xylitol is called a sugar alcohol because of its molecular structure, it doesn’t actually contain any alcohol.
It is found naturally in fruits and vegetables such as strawberries, raspberries, mushrooms and cauliflower, and is actually produced in the body, but in amounts much lower than the amounts added to foods.
Xylitol added to food is not naturally occurring, but is usually synthetic, derived from wood or microbial fermentation. Xylitol is as sweet as sugar, but has 40 percent fewer calories.
Xylitol is less common than other artificial sweeteners, but it’s used in some low-calorie foods that are suitable for the ketogenic diet, Hazen says.
Xylitol-sweetened beverages increased blood xylitol levels 1,000-fold
The researchers measured xylitol concentrations in plasma samples from more than 3,000 healthy subjects who fasted overnight, meaning they measured the amount of xylitol present naturally in the body, rather than coming from food.
The researchers then followed the participants’ health for three years and found that those with the highest post-fasting xylitol levels had nearly twice the risk of heart attack, stroke or death during the follow-up period, compared with those with the lowest post-fasting xylitol levels.
The study didn’t track participants’ diets over the three years, or other factors that may have influenced their risk, and because it was observational, it doesn’t prove that it was high levels of xylitol that increased risk.
To further test this link, researchers fed xylitol to mice, spiked human blood samples with xylitol in the lab, and gave 10 people with the lowest xylitol levels in their bodies a xylitol-sweetened drink. In both studies, they found that xylitol increased the rate at which platelets formed blood clots, which could ultimately lead to heart attacks and strokes.
Secondary studies have shown that consuming products containing xylitol significantly increases the amount of the sugar alcohol in the blood compared with the amount that occurs naturally in the body, Hazen said.
“These are abnormal levels; they’re elevated by 1,000 times,” he says. These levels return to normal within a few hours of ingesting xylitol, but in the meantime, these people may be at significantly increased risk of cardiovascular events, Hazen says.
He acknowledges that the absolute risk of an event occurring during this period is small.
“But who wants to eat something if choosing it as a healthy option means it will move them into a higher risk category for that period of time?” Hazen says.
Low-calorie food manufacturers and suppliers dispute findings
According to the publication, the authors used multiple methods in their study but were able to prove only an association, not a causal relationship.
“These findings are a disservice to people who rely on alternative sweeteners to improve their health. Xylitol has been a trusted, great-tasting, low-calorie sweetener for over 60 years,” said Carla Sanders, president of the Calorie Control Council.
Consumers need to consider risks and benefits
This is a complex study that involves animal studies and observing people immediately after ingesting xylitol, Dr. Slavin says.
“This adds to the evidence on xylitol but does not scare consumers about consuming xylitol in normal small amounts,” she says.
All food ingredients have risks and benefits, and each consumer needs to decide why they are consuming xylitol and whether there are better solutions to their need to eliminate sugar from their diet, Slavin says.
“Alternative sweeteners like xylitol have the benefits of being less cariogenic, lower in calories, less added sugar and sweeter, but can cause gastrointestinal issues if consumed in large amounts. Because obesity and high calorie intake are linked to an increased risk of heart disease and stroke, many consumers will choose to continue using alternative sweeteners like xylitol because of their benefits,” she says.
It’s hard to find foods that contain xylitol
To avoid xylitol altogether, you should examine labels carefully. Foods and drinks labeled “no added sugar” or “no added sugar” should list the amount of sugar alcohols under carbohydrates on the label, but products that don’t make such claims don’t. Instead, they may use terms like “natural sweeteners” or “artificial sweeteners.”
Xylitol may also be listed under other names, including birch sugar and the European code E967. Anything that ends in “ol” indicates it’s a sugar alcohol, according to Hazen.
“Xylitol may be in more products than consumers realize, including energy bars, nut butters and salad dressings,” Hazen says.
Bottom line: Should you avoid products that contain xylitol?
Should you avoid products that contain xylitol? That depends on who you ask.
Hazen advises patients to avoid xylitol, and sugar alcohols in general, and although not all of the different sugar alcohols have been studied and linked to increased risk, he thinks promoting clotting may be an effect they all have in common.
He recommends eating whole foods instead, or, if possible, sweetened with sugar or honey (in moderation).
But Slavin doesn’t think the results of this single study are enough to conclude that using products containing xylitol could be discouraging people from making better health efforts.
“The amounts of xylitol approved for use in the United States are generally considered safe,” she says.
Elisabetta Politi, MPH, CDCES, RD, a diabetes care and education certification specialist at Duke Health in Durham, North Carolina, believes there is insufficient evidence of a causal link from xylitol to tell patients to avoid this sugar alcohol completely.
“Your taste buds are adjustable, so don’t rely too much on artificial sweeteners as excessive intake of them can make you numb to sweetness. I recommend gradually reducing the amount of sugar and sugar substitutes you consume in moderation,” she says.