Sucralose and Carbohydrate Combo May Skew Insulin Sensitivity

By David Douglas

March 15, 2020

NEW YORK (Reuters Health) - The artificial sweetener sucralose appears to have no deleterious effects on its own but in concert with carbohydrates may have a negative metabolic impact, according to new research.

"Our findings help to resolve inconsistent reports in the literature by showing that sucralose decreases brain and metabolic sensitivity to sugar when consumed with but not without a carbohydrate," Dr. Dana Small of Yale University School of Medicine, in New Haven, Connecticut, told Reuters Health by email.

There is general consensus that overconsumption of sugar-sweetened beverages contributes to the prevalence of obesity and its comorbidities such as type 2 diabetes, Dr. Small and colleagues note in Cell Metabolism.

However, there is significant controversy on the effects of consuming no- or low-calorie diet drinks. Some human studies have reported that consumption of low-calorie sweeteners (LCS) is associated with weight gain and diabetes. Others suggest that they lead to weight loss or have no effect at all. There appear to be similar inconsistencies in animal studies.

To investigate, the researchers studied healthy volunteers who were not regular consumers of LCS. Over the course of two weeks they consumed fruit-flavored beverages with added sucralose, or with table sugar. A number had the carbohydrate maltodextrin added to their sucralose drinks. Maltodextrin was also tested as the only additive.

The team did fMRI scans to examine changes in the brain in response to tastes, measurement of taste perception and oral glucose-tolerance testing.

They found that consuming sucralose with, but not without, maltodextrin impaired insulin sensitivity. The effect was correlated with decreases in midbrain, insular and cingulate fMRI responses to sweet taste, but not to sour, salty, or savory tastes.

No changes, the team says, "were observed following equal consumption of beverages with sucralose, sucrose, or maltodextrin alone."

This "does suggest that central circuits, like peripheral glucose tolerance, are altered by the exposure to the LCS only when it is coupled, rather than decoupled, from calories."

These findings "suggest that sucralose consumption alters the metabolism of simultaneously consumed glucose to rapidly produce deleterious effects on metabolic health," the researchers write. "Since the extent of this exposure is very likely experienced in a natural setting, our results provide evidence that LCS consumption contributes to the rise in the incidence of impaired glucose tolerance."

"Have your diet drink," Dr. Small concluded, "but not with French fries."

Dr. Susan E. Swithers of Purdue University, in West Lafayette, Indiana, who has studied sweeteners, told Reuters Health by email, "The study provides clear evidence that consuming low-calorie sweeteners like sucralose for even a short time can lead to metabolic dysregulation in people, consistent with results that have been seen in pre-clinical animal models. These results add to the evidence that experience with consuming low-calorie sweeteners changes metabolic responses to real sugars."

"The demonstration that these effects are seen only when the low-calorie sweetener is consumed along with a carbohydrate not only has implications for understanding the mechanisms involved, but also raises concerns that the large number of food products available that contain these sweeteners may be contributing to metabolic derangements," said Dr. Swithers, who was not involved in the study.

SOURCE: Cell Metabolism, online March 3, 2020.