Sugar Substitutes Might Impact Blood Glucose, Gut Microbiome

Researchers from the US, Germany, and Israel have teamed up to conduct a study on the effects of artificial sweeteners, or non-nutritive sweeteners (NNS), on the human body. Since the introduction of NNS into the mainstream diet, the general public has tended to believe these sweeteners are inert, or able to pass through the body without affecting anything other than the taste of an icy beverage. Compared with sugar, which is known (and sometimes demonized) for its association with diabetes, rapid weight gain, high blood pressure, and other health concerns when over-consumed, this supposed lack of bodily disadvantages has turned NNS into a dietary staple. But the last few years have caused people to question whether NNS are truly “better” for us than regular old sugar.

The immunologists’ and microbiologists’ study, published this month in the journal Cell, doesn’t quite answer that question—but it does get close. The team divided 120 study participants (who did not regularly consume NNS) into six groups. For two weeks, each of the four groups was tasked with consuming a different NNS on a daily basis: stevia, sucralose (Splenda), saccharin (Sweet ‘N Low), and aspartame. Another group consumed only the filler material associated with NNS, as conventional NNS brands typically add extra material to bulk up the tiny bits of actual sweetener contained in each packet. The last group acted as a control group, consuming no NNS at all.

Participants logged all food and drink intake during the study period. They also took oral glucose tolerance tests and provided oral and stool samples, which allowed the researchers to analyze their gut microbiomes. Blood glucose responses were steeper in participants who’d consumed saccharin or sucralose; those who had consumed the former also had increased levels of an amino acid isoleucine, which is typically associated with poor metabolic health. Participants from all four NNS groups experienced changes related to gut bacteria, which have an impact on the body’s ability to exercise glycemic control.

Throughout their paper, the researchers suggest that a body’s reaction to NNS is highly “personalized,” relying heavily on the person’s physiology, diet, and other factors. More research is required to determine whether NNS are “better” or “worse” for humans than traditional sweeteners like cane sugar, and those results are unlikely to apply to those with metabolic disorders like diabetes. Still, the study proves that low-calorie sweeteners aren’t as passive as previously thought.