Sweeteners · Metabolic & Cardiometabolic · Gut & Microbiome
saccharin worsens glucose tolerance
Part of: • saccharin
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
How the studies fall
What the evidence shows
Saccharin is the sweetener with the **strongest microbiome-mediated glucose-intolerance signal**: it was the lead compound in both Suez 2014 (mice + humans) and the Suez 2022 human RCT, where it impaired glycemic responses in susceptible individuals by altering the gut microbiome. As with the class claim, the effect is personalized and not universal — but for saccharin specifically the evidence is
The evidence (8)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Del Pozo et al. 2022 · Nutrients | observational | mixed | moderate | Review: current evidence indicates saccharin (with sucralose) can influence gut-microbiota composition. |
| Suez et al. 2022 · Cell | RCT | supports | high | Human RCT: saccharin impaired glycemic responses via microbiome changes in responsive individuals (lead compound). |
| Conz et al. 2023 · Nutrients | observational | mixed | moderate | NNS–microbiota review: effects real but heterogeneous and personalized. |
| Ruiz-Ojeda et al. 2019 · Adv Nutr | observational | mixed | moderate | Review: saccharin among the few sweeteners that measurably change human gut microbiota. |
| Gauthier et al. 2024 · Nutrition | observational | supports | moderate | Human-trial review: saccharin (with sucralose) changed microbiota/glucose tolerance. |
| Suez et al. 2014 · Nature | animal | supports | moderate | Nature: saccharin was the primary non-caloric sweetener inducing glucose intolerance via gut-microbiota changes (mice + human arm). |
| Al-Ishaq et al. 2023 · Nutrients | observational | mixed | low | Sweeteners–microbiome review: saccharin among agents altering microbiota, clinical relevance debated. |
| Rathaus et al. 2024 · Mol Metab | animal | mixed | low | Long-term NNS study: saccharin metabolic effects context-dependent. |
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