July 09, 2026
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Artificial sweeteners added to coffee and other beverages may impact blood sugar regulation and have other long-term health effects.
People looking to cut calories may want to think twice about using artificial sweeteners.
A study published late last month adds to a growing body of evidence that sugar substitutes, sometimes called non-nutritive sweeteners, have harmful effects on the body.
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The study – a broad review of more than 20 clinical trials, as well as large observational studies – found that artificial sweeteners may have immediate effects on blood sugar levels. The meta-analysis also identified that sugar substitutes may be linked to increased risk of type 2 diabetes and cardiovascular disease.
"What makes our analysis notable is that by focusing on non-caloric comparators, we better isolated the direct physiological effects of the sweeteners themselves, not the calories they replace," said the study's first author, Meng Wang, a research assistant professor at Tufts University. "When pooling findings from individual trials, we see signals that these compounds may have metabolic harms."
A possible explanation for why artificial sweeteners seem to have a harmful effect on cardiometabolic health, which includes heart health, the regulation of blood sugar and other metabolic markers, may involve the gut microbiome. Non-nutritive sweeteners pass through the gut and may alter the gut microbiome and metabolism, the researchers said.
"The rapidly increasing use of these sweeteners has outpaced our understanding of their long-term health effects," said the study's senior author, Dr. Dariush Mozaffarian, a cardiologist and director of the Food is Medicine Institute at Tufts. "Until we know more, caution is needed. If you're replacing large amounts of added sugar in your diet, such as in multiple servings of soda, these low-calorie sweeteners may be a better alternative. But we can't simply assume they are safe and innocuous, and avoiding them whenever possible appears a prudent choice."
Another study, published last year, found an association between frequent use of artificial sweeteners and faster decline in cognitive, memory and verbal abilities.
Non-nutritive sweeteners are FDA-approved, low-calorie alternatives to sugar. They can be synthetic or naturally-derived and are found in a range of products, from diet soda to protein bars to sugar-free gum. They are also used as coffee sweeteners.
Examples of these sugar substitutes include Splenda (sucralose), Sweet'N Low (saccharin) and Stevia and Truvia, which are derived from the leaves of the Stevia plant.
Food manufacturers are required to list which non-nutritive sweeteners are used in their products, but not the amount. This complicates efforts to study their impact on overall health, the Tufts researchers said.
