When people hear that sugar-sweetened beverages pose health hazards, some respond by switching to diet soft drinks. That certainly seems reasonable, but evidence now suggests it might not be the best strategy. Non-sugar sweeteners may not offer the expected advantages (The BMJ, Jan. 3, 2019). In fact, regular users may be at higher risk for cardiovascular disease (The BMJ, Sept. 7, 2022). In addition to the epidemiological evidence from France, we have recent scientific experiments from the Cleveland Clinic that cast doubt on the safety of some popular sugar substitutes.
What We Can Learn from 100,000 French Men & Women:
NutriNet-Santé, a cohort study of more than 100,000 French adults, has uncovered risks of non-sugar sweeteners such as aspartame, sucralose and acesulfame potassium. When the volunteers entered the study, they answered detailed questionnaires about diet and physical activity as well as demographic and health information. In addition, they responded to dietary questionnaires approximately every six months. About 37 percent of the participants reported regular consumption of artificial sweeteners. Average sweetener intake among these people was about one packet or tablet daily (42 mg/day).
Over the course of ten years, people using sugar substitutes were slightly more likely to develop cardiovascular disease. In particular, aspartame users were about 18 percent more likely to have strokes, while those using sucralose or acesulfame potassium were 30 to 40 percent more likely to develop coronary heart disease.
According to the investigators,
“Our results suggest no benefit from substituting artificial sweeteners for added sugar on CVD [cardiovascular disease] outcomes.”
What Are the Effects of Non-Sugar Sweeteners?
Sweeteners That Promote Blood Clots:
Xylitol:
Xylitol is a natural low-calorie sweetener that is frequently used as a sugar substitute. It can be found in chewing gum, toothpaste, candy, ice cream, peanut butter and baked goods. New research indicates that xylitol increases the clotting potential of platelets (European Heart Journal, June 6, 2024). This in turn might lead to an increased risk for problems such as heart attacks, strokes and pulmonary embolisms.
The Cleveland Clinic investigators identified xylitol as a potential risk factor from a large panel of blood samples. Then they examined the effect of this sugar alcohol on platelet function. Finally, they gave volunteers a xylitol-rich drink and studied how platelet performance changed. They concluded that xylitol can enhance platelet reactivity. As a result, they believe this sugar substitute could increase the risk for major adverse cardiovascular events.
Erythritol:
Xylitol is not the first sweetener to come under suspicion. A study in 2023 showed that erythritol may encourage blood clots that can lead to heart attacks and strokes. This sugar substitute has become quite popular because it looks and tastes like sugar but does not contribute calories. As a result, manufacturers often add it to the “natural” sweeteners derived from monk fruit or stevia so that they will behave more like sugar. Just how safe is it?
Scientists at the Cleveland Clinic analyzed blood samples in people at high risk for cardiovascular complications (Nature Medicine, Feb. 27, 2023). They found that those with high levels of erythritol in their blood were more likely to suffer a heart attack or stroke or even to die in the next three years after the blood was drawn.
Blood exposed to erythritol clots more readily. As a result, the risk for heart attacks and strokes climbs when people consume it. It doesn’t take very much erythritol to cause trouble, either. Just 30 grams of the sweetener was enough to make blood levels skyrocket. That’s about as much as you might find in a pint of keto ice cream.
Sugar substitutes are more likely to appear in foods marketed to people with diabetes, overweight or other risk factors for cardiovascular diseases. In light of this, the researchers conclude, “Studies assessing the long-term safety of erythritol are warranted.” Presumably, they would now add xylitol to the list of non-sugar sweeteners that should be investigated more thoroughly.
Readers Wonder About Sweetener Safety:
Is Erythritol Linked to Strokes?
Q. What can you tell me about studies showing that the non-sugar sweetener, erythritol, can contribute to strokes and heart attacks by altering blood platelets? I still see products that contain it, and you can even buy erythritol by itself!
I had a stroke last year, and I had a bag of erythritol in my cupboard thinking it would be a healthy substitute for white sugar! Heart attacks and strokes cause many deaths every year. Shouldn’t this be better known?
A. You are right that people at risk for cardiovascular disease with high levels of erythritol in their blood were more likely to suffer heart attacks or strokes, according to the research published in Nature Medicine (Feb. 27, 2023). We agree that more information about this potential risk is needed. Too few people realize that non-sugar sweeteners may pose health risks beyond the possibility of loose bowels.
Monkfruit Mixed with Erythritol:
Q. Instead of sugar, I’ve been sweetening my coffee and breakfast cereal with monkfruit for a couple of years. The sweetener also contains erythritol. Now I’ve read that can be a problem. How concerned should I be about the effect on my arteries?
A. Most people think of erythritol as a natural sugar substitute and assume that it is perfectly safe. It is natural, but new research (above) suggests that people who use this sweetener regularly may be more prone to heart attacks or strokes. Apparently the problem is that erythritol promotes blood clots. If you stop using the sweetener, your risk should drop to normal within several days or so.
Earlier Studies on the Safety of Non-Sugar Sweeteners:
NutriNet-Santé was the largest study but not the first to cast doubt on the benefits of artificial sweeteners. In a previous analysis published in The BMJ in 2019, researchers reviewed 56 studies of non-sugar sweeteners. They found “no compelling evidence to indicate important health benefits.”
In most of these studies comparing outcomes for people consuming artificial sweeteners to those for people consuming none, there were no significant differences. In a few small studies, people using sugar substitutes had lower fasting blood sugar and slightly better body mass index. However, these findings were statistically uncertain. Previous research has not shown strong evidence that such sweeteners help people lose weight.
Are Artificial Sweeteners Safe?
The researchers point out that these studies did not adequately address questions of safety. They call for longer-term, better-designed trials to establish clearer conclusions on safety and effectiveness of sugar substitutes. (NutriNet-Santé might have been designed partly with this request in mind.)
An earlier study found some unexpected effects of such sweeteners that may have a bearing on safety. In particular, these compounds may affect the balance of microbes that inhabit our intestines. This, in turn, could have an impact on inflammation.
Non-Sugar Sweeteners May Change Metabolism:
In addition, test tube research suggests that the artificial sweetener sucralose can alter the metabolism of stem cells from fat tissue. (Stem cells are capable of becoming many different types of tissue cells, for example, muscle or bone as well as fat.)
These human cells churned out more compounds associated with inflammation and fat storage when they were exposed to sucralose. The dose was equivalent to someone drinking four cans of diet soda a day. The stem cells also showed changes in their genes that indicate fat production.
Could Sugar-Free Drinks Be Counterproductive?
If these “in vitro” laboratory results hold up in animals and humans, heavy consumption of non-sugar sweeteners could lead to fat accumulation rather than fat and weight loss. The scientists also discovered other signs of metabolic disruption due to non-sugar sweeteners. They are concerned that these changes were most noticeable in people who are already overweight or obese.
The researchers note:
“we believe that low-calorie sweeteners promote additional fat formation by allowing more glucose to enter the cells, and promotes inflammation, which may be more detrimental in obese individuals.”
Sen et al, Endocrine Society annual meeting, Orlando, FL, April 3, 2017
