A new review from Tufts University shows that non-caloric sweeteners can negatively affect blood sugar metabolism and gut flora. The analysis of randomized studies revealed evidence of increased fasting insulin levels and a rise in the long-term blood sugar value HbA1c. The researchers advise caution when consuming these substances. The work was published in Current Atherosclerosis Reports.
Background
Non-caloric sweeteners such as saccharin, aspartame, or sucralose are widely used in many foods and beverages. They are considered a safe alternative to sugar because they provide no calories. However, recent research suggests that these substances are not inert and can affect metabolism and gut microbiota.
Important findings
In the analysis of 21 randomized clinical trials, non-nutritive sweeteners increased fasting insulin levels and HbA1c compared to non-caloric control substances. In addition, changes in the composition and function of gut bacteria were observed. Observational studies suggest an increased risk of cardiometabolic diseases, although confounding factors must be considered here.
Methodology
The researchers evaluated randomized studies that compared sweeteners with non-caloric controls (e.g., water or placebo). This allowed them to better isolate the direct physiological effects of the sweeteners than in studies that compared them with sugar. In addition, large observational studies and an investigation involving microbiome analyses and fecal transfers from humans to mice were included.
Practical recommendation
The authors emphasize that non-caloric sweeteners may represent the better alternative for individuals with high sugar consumption (e.g., several sodas daily). Nevertheless, they are not currently justified to be classified as completely harmless. Wherever possible, they should be avoided until more long-term data are available.
Outlook
The researchers call for further randomized long-term studies on cardiometabolic risks and the underlying mechanisms. At the same time, they criticize the current US labeling requirements, which do not require the declaration of exact quantities, thus complicating population-based studies.
FAQ
What did the researchers investigate?
The effects of non-caloric sweeteners on metabolism and gut flora in randomized studies.
What effects were observed?
Increased fasting insulin levels, rise in HbA1c, and changes in gut microbiota.
Are sweeteners safer than sugar?
For very high sugar consumption, they may be the better alternative. Nevertheless, the researchers advise caution.
What do the authors recommend?
Avoid non-caloric sweeteners as much as possible until more long-term safety data are available.
Why are further studies necessary?
To better understand the long-term effects on cardiovascular diseases and metabolism.
