Sucralose, blood sugar and gut bacteria over seven days in healthy men
What it found
Taking 780 mg of sucralose daily for seven days made no difference to blood sugar, insulin or gut bacteria in healthy men.
People whose insulin rose more during the trial had different gut bacteria at the start, regardless of what they took.
What they found
Studies in people
Blood sugar and insulin
After seven days, fasting blood sugar and insulin levels were about the same in both groups. Taking sucralose did not change how the men handled a sugary drink compared with the placebo.
Gut bacteria unchanged
The overall mix of gut bacteria stayed the same in both groups over the seven days. Sucralose did not shift the main bacterial groups compared with the placebo.
Body weight stable
Body weight barely changed in either group during the week. No one reported any unwanted side effects from taking the capsules.
Insulin responders and bacteria
Some men had a bigger rise in insulin after the week than others, regardless of which capsules they took. Those men started with more Firmicutes and fewer Bacteroidetes bacteria in their guts.
Other findings
Dose used in study
Each man took three capsules a day, totalling 780 mg of sucralose. This equals 75 % of the acceptable daily intake for someone weighing 70 kg.
What the authors conclude
- They conclude that taking high doses of sucralose for seven days did not change blood sugar control, insulin resistance or gut bacteria in healthy men.
- They note that individual differences in insulin responses seemed linked to gut bacteria rather than to the sweetener itself.
- They advise that future research should look into why people respond differently to sucralose.
How it was done
Sucralose is widely used to replace sugar, but animal studies suggest it might change how the body handles glucose by altering gut bacteria. The authors wanted to check whether this happens in people over a short period.
Thirty-four healthy men aged 18 to 50 took capsules three times a day for seven days. Sixteen men got 780 mg of sucralose daily and fourteen got a placebo. Researchers measured their blood sugar, insulin and gut bacteria before and after.
What it can’t tell you
- This trial only included healthy men, so the results may not apply to women, children or people with diabetes.
- Seven days is a very short time, so this cannot show what happens when people take sucralose for months or years.
- The dose was much higher than most people get from food, which is typically up to 15 % of the acceptable daily intake.
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 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error