Sucralose and saccharin effects on gut bacteria
What it found
In lab tests and animal studies, sucralose and saccharin changed gut bacteria in a dose-dependent way.
In people, short-term studies using amounts below the daily limit found no significant changes, but one long-term study found a link with some bacterial groups.
What they found
Studies in people
Short-term human studies
Most short-term human studies using amounts below the acceptable daily intake found no significant changes in gut bacteria diversity or composition. For example, a 2-week study with 46 people taking saccharin found no changes, and a 1-week study with 34 men taking sucralose found no changes at the phylum level.
Long-term human study
One long-term study with 381 non-diabetic people found a link between artificial sweetener consumption and some bacterial groups, but the authors note that other factors could not be ruled out.
Personalized response
In one study, only 4 out of 7 healthy volunteers showed changes in gut bacteria after taking saccharin for one week. The authors suggest that people may respond differently based on their starting gut bacteria.
Animal and lab studies
Lab tests on bacteria
In lab tests, sucralose and saccharin affected bacterial growth and communication. One study found sucralose increased valeric acid and changed the types of bacteria in fermented fecal samples from 13 healthy volunteers.
Animal studies
In mice and rats, sucralose and saccharin changed the balance of gut bacteria, often in a dose-dependent way. Some studies found increases in Firmicutes and decreases in Bacteroidetes, while others found different effects depending on the dose.
What the authors conclude
“In conclusion, it is necessary to broaden the concept of food safety for sucralose and saccharin by re-evaluating toxicity referring to the effect on the gut microbiota and the possible consequences on health maintenance and disease amelioration in humans.”
Also in their conclusions
- They say it is necessary to broaden the concept of food safety for sucralose and saccharin by re-evaluating toxicity related to gut bacteria effects.
- They advise that clinical trials should include enough subjects and consider their baseline gut bacteria, dietary habits, and lifestyles.
- They call for more studies in vulnerable groups such as children, the elderly, pregnant women, and people with intestinal or metabolic conditions.
How it was done
The authors wanted to update the evidence on how consuming different amounts of saccharin and sucralose affects gut bacteria in short- and long-term studies.
They searched scientific databases for studies on saccharin and sucralose and gut bacteria. They included 6 lab studies, 14 animal studies, and 4 human studies.
What it can’t tell you
- Lab and animal studies cannot show what happens in people.
- The long-term human study can show a link but not prove that sweeteners caused the changes.
- Most human studies were short and used small numbers of people, so they cannot show long-term effects.
Who paid
- Conflicts
- The authors declare no conflict of interest.
- Authors work at
- Complutense University of Madrid, Spain; Institute of Food Science, Spain; San Pablo CEU University, Spain
The paper
- Title
- Potential Effects of Sucralose and Saccharin on Gut Microbiota: A Review
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Del Pozo S, Gómez-Martínez S, Díaz LE, Nova E, Urrialde R, Marcos A (2022). Potential Effects of Sucralose and Saccharin on Gut Microbiota: A Review. Nutrients. doi:10.3390/nu14081682Free full textPubMed 35458244DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error