Aspartame, gut bacteria and brain tumour growth in mice
What it found
In mice with brain tumours, aspartame changed the mix of gut bacteria and altered gene activity in the tumours but did not change how fast the tumours grew.
The work was done in animals, not people.
What they found
Animal and lab studies
Tumour growth unchanged
The aspartame water did not make the brain tumours grow faster or slower compared with plain water over the 15 days in these mice.
Gut bacteria shifted
Mice given aspartame had fewer bacteria from a group called Rikenellaceae in their guts. Two other bacterial groups also differed between the aspartame and plain water groups.
Gene activity changed
In the mouse brain tumours, 6,146 genes showed different activity levels after aspartame. Many of these genes are linked to cell division and cancer pathways.
Studies in people and animals
Key tumour genes rose
Three specific genes, MYC, CDKN1A and TGFB1, were more active in the tumours of mice that drank aspartame. A check of human patient data found that higher TGFB1 is linked to worse outcomes in people with this brain tumour.
What the authors conclude
- They conclude that aspartame did not change how fast the brain tumours grew in their mice, but it did shift gut bacteria and raise the activity of certain genes in the tumours.
- They suggest that one of those genes, TGFB1, could be important in how aspartame affects this type of brain tumour through chemical tags on genes.
- They call for larger studies that look at both sexes and examine the breakdown products of aspartame.
How it was done
Scientists wanted to know if aspartame changes gut bacteria and gene activity during the growth of a type of brain tumour called glioblastoma. They noted that gut bacteria can send signals to the brain and might affect how these tumours behave.
Researchers gave 5 female mice drinking water with aspartame at 50 mg per kg of body weight for 15 days. Another 5 mice got plain water. All 10 mice had brain tumours grown from implanted cells, and the team checked their gut bacteria, gene activity and tumour size.
What it can’t tell you
- These results come from just 10 mice with implanted brain tumours, so they cannot show what happens in people who eat or drink aspartame.
- The study lasted only 15 days, which does not reveal any effects from long-term use.
- Because the researchers looked at many genes at once in a small number of animals, some of the differences they spotted could be due to chance.
Who paid
- Funding
- Funded by Guangxi Academy of Agricultural Science and Technology Development Project; the Guangxi Major Science and Technology Program; Guangxi Academy of Agricultural Sciences Basic Research Project; Guangdong 3D Orthopedics Biomimetic Translational Medicine Engineering Technology Research Center (from the PubMed record).
- Conflicts
- Declarations. Competing interests: The authors declare no competing interests. Ethics approval and consent to participate: This study was reviewed and approved by the Institutional Review Board of Guangxi Medical University (Ethics: 202307007). All methods were carried out in accordance with the relevant guidelines and regulations, and in compliance with the ARRIVE guidelines ( https://arriveguidelines.org ).
- Authors work at
- Guangxi Subtropical Crops Research Institute, China; Ministry of Agriculture and Rural Affairs, China; Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Colleges and Universities Key Laboratory of Prevention and Control of Highly Prevalent Diseases, China
The paper
- Title
- Metagenomics and transcriptomics analysis of aspartame's impact on gut microbiota and glioblastoma progression in a mouse model
- Type
- Study
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Meng K, Bao Y, Chen G, et al (2025). Metagenomics and transcriptomics analysis of aspartame's impact on gut microbiota and glioblastoma progression in a mouse model. Scientific reports. doi:10.1038/s41598-025-06193-5Free full textPubMed 40604039DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error