Sweeteners · Gut & Microbiome
acesulfame-K alters gut microbiome
Part of: • acesulfame-K
📅 Last reviewed: 2026-07-15 ⓘ
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: Animal studies (Animal)
How the studies fall
What the evidence shows
Acesulfame-K's effect on the human gut microbiome is weakly supported — some reviews and animal work suggest it can shift microbiota, but the human clinical trials that changed microbiota implicated saccharin and sucralose, not ace-K. So, like aspartame, the microbiome concern for ace-K specifically is largely mechanistic/animal, not demonstrated in people.
The evidence (16)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Feng et al. 2024 · Metabolites | animal | supports | low | NAS-microbiome review: ace-K effects sporadic, human data limited. |
| De Paepe E et al 2025 · study_type: observational | observational | tested-null | low | In salivary metabolomics of 1436 European children/adolescents, Ace-K (detected for the first time in this biofluid) correlated weakly with excess weight, stress, diet, and Bacillota phylum abundance (|rho|<0.2). |
| Khattab 2026 · Curr Nutr Rep | observational | supports | low | Mechanistic review: ace-K among sweeteners that can modulate microbiota (largely preclinical). |
| Kidangathazhe A et al 2025 · study_type: in-vitro | in-vitro | supports | low | Minibioreactor arrays inoculated with human fecal samples (n=3 donors) over 35 days: Ace-K increased overall microbial diversity but disrupted co-occurrence network structure, described as a persistent structural change distinct from sucral |
| Al-Ishaq et al. 2023 · Nutrients | observational | supports | low | Sweeteners-microbiome review: ace-K evidence sparse/inconclusive. |
| Jin X et al 2026 · study_type: in-vitro | in-vitro | mixed | low | Five sweeteners including Ace-K tested on E. coli/B. subtilis monocultures at CAC-permitted doses; Ace-K (like others except saccharin) did not significantly affect bacterial growth but was associated with reduced antibiotic susceptibility |
| Iizuka 2022 · Nutrients | observational | mixed | low | Review: artificial sweeteners incl. ace-K may alter microbiota, evidence mixed. |
| Bellanco A et al 2026 · study_type: in-vitro | in-vitro | supports | moderate | Dynamic gut simulator (children's fecal inoculum) showed Ace-K dose-dependent shifts in Anaerostipes, Coprococcus, Subdoligranulum, Blautia, Sutterella, Alistipes, B. thetaiotaomicron, plus dose-dependent decrease in Caco-2 epithelial barri |
| Blasche S et al 2026 · Molecular Systems Biology | in-vitro | supports | moderate | Screening of 25 gut bacterial strains against 39 sweeteners (including Ace-K) individually and in combination with co-consumed xenobiotics found three-quarters of tested sweeteners individually impacted growth of at least one bacterial stra |
| Gauthier et al. 2024 · Nutrition | observational | contradicts | moderate | Human clinical-trial review: only saccharin and sucralose changed microbiota — not ace-K. |
| Del Pozo et al. 2022 · Nutrients | observational | tested-null | low | Review focused on sucralose/saccharin: ace-K evidence sparse. |
| Marongiu L et al 2025 · study_type: observational | observational | mixed | low | Narrative review naming acesulfame potassium among seven NNS assessed for effects on human intestinal microbiota; concludes NNS intake is 'linked' to dysbiosis in animals and humans via altered bacterial biochemistry and quorum sensing, wit |
| Conz et al. 2023 · Nutrients | animal | mixed | low | NNS–microbiota review: ace-K among sweeteners reported to affect microbiota (largely preclinical). |
| Chowdhury CR et al 2026 · study_type: observational | observational | mixed | moderate | Ace-K-focused review: human studies generally confirm safety within ADI, but preclinical (in vitro/in vivo) models report altered gut microbiota composition, lipid metabolism, and inflammatory/gene-expression pathways, mostly at supraphysio |
| Raoul PC et al 2025 · study_type: animal | animal | mixed | moderate | PRISMA-registered systematic review of 37 animal studies (aspartame n=17, sucralose n=16, Ace-K n=5, saccharin n=4) on inflammatory markers; concludes Ace-K and saccharin showed 'variable, dose-dependent effects' versus more consistent elev |
| Ruiz-Ojeda et al. 2019 · Adv Nutr | observational | mixed | moderate | Review: only saccharin, sucralose and stevia measurably change human gut microbiota — implying ace-K does not. |
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