Artificial Sweeteners May Disrupt Metabolism and Gut Health
New research published in the journal Current Atherosclerosis Reports reveals that artificial or non-calorie sweeteners may affect the body in unexpected ways. New evidence suggests a link between the consumption of these sweeteners and changes in metabolism and gut health.
Researchers from the Food is Medicine Institute at Tufts University conducted a review of 21 randomised clinical trials in adults and performed a meta-analysis to assess the impact of non-nutritive sweeteners on cardiometabolic health. The study covered various types of low-calorie sweeteners commonly found in diet drinks, sugar-free chewing gum, and protein bars.
“What makes our analysis stand out is that by focusing on non-calorie comparators, we were able to isolate the direct physiological effects of the sweeteners themselves, rather than because of the calories they replace,” said Meng Wang, a research assistant professor at the institute and the study’s lead author.
These findings challenge the long-held assumption that artificial sweeteners are metabolically inert, meaning they simply pass through the body without affecting biological processes. When compared to non-calorie controls such as water or a placebo, sweetener consumption was associated with higher fasting insulin levels and increased HbA1c, which is a marker for long-term blood sugar control. The analysis also found a trend towards worsening insulin sensitivity.
Bryan Quoc Le, a food scientist and author of ‘150 Food Science Questions Answered’, provided an important note. Despite these findings, the benefits of reducing sugar intake should not be ignored. “We know that long-term high sugar consumption leads to many chronic conditions, so the benefits of replacing sugar are well-known and established,” he told Newsweek.
One potential explanation for this effect involves the gut microbiome, the community of microbes in the digestive tract that plays a crucial role in immunity and metabolic health. Artificial sweeteners typically pass through the intestines and come into direct contact with these microorganisms.
The review showed evidence that certain low-calorie sweeteners alter the composition and function of gut bacteria. Researchers used detailed microbiome profiling and microbial transfer experiments from humans to mice to identify these changes.
However, Le emphasised that whether these microbiome changes truly result in long-term health consequences remains a subject of debate. “This is still a matter of discussion, especially given the complexity of the gut microbiome, individual variations, and the different types of sweeteners at varying concentrations over time,” he added.
Experts warn that the category of non-nutritive sweeteners is very broad, encompassing synthetic products such as aspartame, saccharin, and acesulfame potassium, as well as natural alternatives like stevia and monk fruit. Researchers noted that each type of sweetener may have different biological effects, meaning some may be more problematic than others.
In addition to clinical trials, the authors also reviewed large-scale population observational studies that found a link between non-nutritive sweeteners and a higher risk of cardiometabolic diseases. Nevertheless, observational studies cannot prove causation, as there is a possibility that individuals already at high risk of disease tend to choose low-calorie sweeteners.