Are low-calorie sweeteners a healthy substitute for sugar?
By Carrie Dennett, MPH, RDN
Most people who are trying to limit added sugar include some type of sugar substitute in their diets. But whether you’re talking about artificial sweeteners or “natural” low-calorie sweeteners, sugar substitutes are not without controversy. It’s a controversy that was stirred up earlier this year by a study published in the journal Nature Medicine that looked at levels of polyol sweeteners in the blood of patients undergoing a cardiac risk assessment.
Polyols, also known as sugar alcohols, are found naturally in small amounts in certain fruits vegetables and mushrooms. Other than for people who have trouble tolerating polyols, such as many people with irritable bowel syndrome (IBS), naturally occurring polyols aren’t the issue. However, isolated polyols—examples include sorbitol, mannitol, xylitol and erythritol—are used as sugar-free, low-calorie sweeteners in many food products, from chewing gum to candy to energy bars to protein powders. That might be a problem.
This study found that that among the 1,157 patients tested, those with the highest levels of polyols—especially erythritol—circulating in their blood were more likely to have a heart attack or stroke in the following three years. Now, this study doesn’t prove cause-and-effect, but it does raise some concerns. Specifically, researchers said it appears that erythritol may contribute to blood clots, which could break free and block arteries, causing heart attacks and strokes.
To confirm this, the researchers examined two more groups of people (2,982 total). They found that the 25% of people with the highest erythritol levels were twice as likely to have a heart attack or stroke in the next three years when compared with the 25% of people with the lowest erythritol levels. To figure out what was happening in the bloodstream after consuming erythritol, they had eight healthy volunteers drink a beverage sweetened with erythritol and then checked their blood. The volunteers’ blood levels of erythritol increased by 1,000-fold and stayed greatly elevated for several days. For at least two days, levels were high enough to trigger changes in blood platelets that can lead to clotting.
Erythritol and other isolated polyols have been popular because they are “natural” and taste more like real sugar than artificial no-calorie sweeteners do. Erythritol, which is produced by using a type of yeast to ferment glucose from corn or wheat starch, has 6% of the calories of sugar, but tastes 70% as sweet.
These recent studies, along with and other human research, is raising questions about the wisdom of freely using artificial or low-calorie sweeteners. In a nutshell, it appears that these sweeteners are not merely inert substances that help people avoid sugar. They may have actual effects, including some negative ones. But it’s clear we need more research to be certain.
A black-or-white approach to nutrition is generally not necessary or wise, and this is one of those times. It may be simply that with both sugar and sugar substitutes added to foods and beverages, it’s the amount that matters. If you consume a lot of foods and beverages that use polyols or other sugar substitutes, you might ask yourself why. Many products containing erythritol or other sugar alcohols have a “health halo,” whether they’re marketed as being healthy or we just assume they are because they contain less sugar.
If you want to avoid eating or drinking excess erythritol, other non-sugar sweeteners such as stevia, allulose, and lucuma may be good substitutes (note that allulose can cause digestive distress in some people, but so can polyols). Monk fruit extract is a popular option, but make sure that it’s not combined with other low-calorie sweeteners such as erythritol. Monk fruit extracts can also vary widely in sweetness.
Witkowski M, Nemet I, Alamri H, et al. The artificial sweetener erythritol and cardiovascular event risk. Nat Med. 2023 Mar;29(3):710-718. https://www.nature.com/articles/s41591-023-02223-9
National Institutes of Health. Erythritol and Cardiovascular Events. March 14, 2023. https://www.nih.gov/news-events/nih-research-matters/erythritol-cardiovascular-events