Sucralose, blood sugar and gut bacteria in healthy men
What it found
In 30 healthy men, taking high doses of sucralose for 7 days did not change blood sugar control, insulin resistance or gut bacteria.
Some men had different insulin responses, but this happened with placebo too.
What they found
Studies in people
Blood sugar control
Fasting blood sugar and the blood sugar response to a glucose drink were similar before and after the intervention in both groups. No difference was found between sucralose and placebo.
Insulin resistance
Measures of insulin resistance and sensitivity did not change over the 7 days in either group. The authors found no effect of sucralose compared with placebo.
Gut bacteria
The types and amounts of gut bacteria stayed stable over the week in both groups. No major changes were linked to taking sucralose.
Individual insulin responses
Men who had a higher insulin response after the intervention, whether they took sucralose or placebo, had different gut bacteria: more Firmicutes and fewer Bacteroidetes. This pattern was also seen in people with higher BMI or insulin resistance markers.
Body weight and side effects
Body weight stayed the same in both groups. No one reported side effects or changes in their usual diet.
What the authors conclude
“consumption of high doses of sucralose for 7 d does not alter glycaemic control, insulin resistance, or gut microbiome in healthy individuals.”
Also in their conclusions
- They conclude that high doses of sucralose for 7 days do not alter glycaemic control, insulin resistance, or gut microbiome in healthy individuals.
- They highlight the need to address individual responses to sucralose.
- They suggest further studies should include potential responder–non-responder differences among subjects.
How it was done
Sucralose is widely used in foods and drinks, and some studies in mice suggest it might affect metabolism through gut bacteria. The authors wanted to see if this happens in people over a short period.
They gave 34 healthy men either sucralose capsules (780 mg per day) or placebo for 7 days. Before and after, they measured blood sugar and insulin after a glucose drink, and analysed gut bacteria from stool samples.
What it can’t tell you
- This was a short study in healthy men, so it cannot show what happens over longer periods or in women, children, or people with health conditions.
- The study was not designed to look at gut bacteria, so it may have missed small changes.
- It cannot prove that sucralose causes any long-term health effects.
Who paid
- Authors work at
- School of Engineering, Chile
The paper
- Title
- Short-term impact of sucralose consumption on the metabolic response and gut microbiome of healthy adults
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Thomson P, Santibañez R, Aguirre C, Galgani JE, Garrido D (2019). Short-term impact of sucralose consumption on the metabolic response and gut microbiome of healthy adults. The British journal of nutrition. doi:10.1017/S0007114519001570Free full textPubMed 31258108DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error