Are Nonnutritive Sweeteners Obesogenic? Associations between Diet, Faecal Microbiota, and Short-Chain Fatty Acids in Morbidly Obese Subjects

J Obes. 2019 Oct 1:2019:4608315. doi: 10.1155/2019/4608315. eCollection 2019.


Obesity has been associated with changes in the gut microbiota and its metabolites. The study explored changes in the faecal microbiota and short-chain fatty acids (SCFA) associated with the diet (including nonnutritive sweeteners (NNSs)) and evaluated metabolic consequences in subjects with morbid obesity. The diet was assessed with a validated food frequency questionnaire. One unit of NNSs was 100 mL beverage with NNSs or 2 tablets/teaspoons of NNSs. The faecal microbiota was assessed with GA-map® dysbiosis test and SCFA with gas chromatography and flame ionisation detection. Fourteen men and 75 women with a mean age of 44.6 (SD 8.7) years, BMI 41.8 (SD 3.6) kg/m2, and intake of NNSs 7.5 units/day (SD 3.2; range 0-43) were included. Faecal butyric acid was positively and negatively associated with the intake of starch (partial correlation = 0.264; p=0.015) and NNSs (partial correlation = -0.274; p=0.011), respectively. NNSs were associated with changes in four out of 39 bacterial groups. Butyric acid has antiobesogenic effects, reduces insulin resistance, and improves dyslipidaemia. Since the weight-reducing effect of NNSs on obese adults trying to lose weight is dubious, it seems imprudent to use NNSs that might counteract the favourable effects of butyric acid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Butyric Acid / metabolism*
  • Cross-Sectional Studies
  • Diet
  • Fatty Acids, Volatile
  • Feces / microbiology*
  • Female
  • Gastrointestinal Microbiome / drug effects*
  • Humans
  • Male
  • Middle Aged
  • Non-Nutritive Sweeteners / adverse effects*
  • Non-Nutritive Sweeteners / pharmacology
  • Obesity, Morbid / drug therapy*
  • Sweetening Agents / adverse effects*
  • Sweetening Agents / pharmacology
  • Young Adult


  • Fatty Acids, Volatile
  • Non-Nutritive Sweeteners
  • Sweetening Agents
  • Butyric Acid