Sweeteners · Gut & Microbiome

acesulfame-K alters gut microbiome

Insufficient(Laboratory findings not confirmed in people) Sweeteners 🐭 Non-human evidence🔬 Includes disconfirming

RefutedContestedStrong support

consensus score 0.41

⚖️ Thin evidence — read the needle loosely. The score shows which way the studies lean, but there are too few independent, high-quality ones to place it firmly. Expect this to move as better evidence arrives.

Why the rating is limited: laboratory findings not confirmed in people.

The studies supporting this claim are animal or laboratory studies. Human studies have tested it without finding the claimed effect, or have found evidence against it.

Before this limit: leans support. Final rating: insufficient.

🧭 Read this score with how it was built in mindLab and animal results no longer outvote a human study that found nothing

Four animal and cell studies support it; the one human study, in 1,436 children and adolescents, found at most a very weak association.

📅 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)

MechanismIn-vitroAnimalObservationalRCTMeta-analysis

How the studies fall

4 support 0 contradict 1 tested null 3 mixed · 8 sources, 4 independent groups

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 J, Peng J, Hsiao YC, Liu CW, Yang Y, Zhao H, Teitelbaum T, Wang X, Lu K 2024 · Metabolites	animal	supports	low	NAS-microbiome review: ace-K effects sporadic, human data limited.
De Paepe E, Callemeyn E, De Windt K, Wijnant K, Plekhova V, Pomian B, Vangeenderhuysen P, De Henauw S, Michels N, Viljakainen H, Leppänen MH, Lakka TA, Van De Maele K, Baeck N, De Bruyne R, Lefere S, Geerts A, Vynck M, Vanhaecke L 2025 · EBioMedicine	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 R 2026 · Curr Nutr Rep	observational	supports	low	Mechanistic review: ace-K among sweeteners that can modulate microbiota (largely preclinical).
Kidangathazhe A, Amponsah T, Maji A, Adams S, Chettoor M, Wang X, Scaria J 2025 · Frontiers in Microbiology	in-vitro	supports	low	Ex-vivo minibioreactor arrays inoculated with faecal microbiota from 3 healthy donors (4 replicates), sweetener days 7-21, withdrawal to day 35. Acesulfame K (290.6 mg/L) gave the largest rise in Observed/Chao1/ACE diversity, the strongest Bacillaceae enrichment, and a network that lost modularity and split into isolated islands that persisted after withdrawal: 'acesulfame K has a more lasting impact on the network properties and interactions.' Descriptive analysis, no test statistics; in-vitro, not in-vivo human microbiota.
Al-Ishaq RK, Kubatka P, Büsselberg D 2023 · Nutrients	observational	supports	low	Sweeteners-microbiome review: ace-K evidence sparse/inconclusive.
Jin X, Xu J, Cao Y, Dai Z, Wang R, Ge X, Cai R, Hu Z, Sun X, Chen J, Zhang L 2026 · Infection and drug resistance	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 K 2022 · Nutrients	observational	mixed	low	Review: artificial sweeteners incl. ace-K may alter microbiota, evidence mixed.
Bellanco A, Yépez-Notario C, Lozano M, Martínez-Cuesta MC, Requena T 2026 · Journal of agricultural and food chemistry	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, Periwal V, Beristain Covarrubias N, Lindell A, Roux I, Kamrad S, Mozzachiodi S, Bradley R, Ozgur H, Ramachandran B, Benes V, Patil KR 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 E, Milagro FI, Navas-Carretero S 2024 · Nutrition	observational	contradicts	moderate	Human clinical-trial review: only saccharin and sucralose changed microbiota — not ace-K.
Del Pozo S, Gómez-Martínez S, Díaz LE, Nova E, Urrialde R, Marcos A 2022 · Nutrients	observational	tested-null	low	Review focused on sucralose/saccharin: ace-K evidence sparse.
Marongiu L, Brzozowska E, Hetjens S, Hoelzle LE, Venturelli S 2025 · Frontiers in nutrition	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 A, Salmona M, Diomede L 2023 · Nutrients	animal	mixed	low	NNS–microbiota review: ace-K among sweeteners reported to affect microbiota (largely preclinical).
Chowdhury CR, Havlik J 2026 · Food chemistry	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, Romano M, Galli FS, Cintoni M, Capristo E, Mora V, Mele MC, Gasbarrini A, Rinninella E 2025 · Nutrients	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 FJ, Plaza-Díaz J, Sáez-Lara MJ, Gil A 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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