Vinegar intake and immunotherapy response in Japanese cancer patients
What it found
In 32 Japanese patients receiving immune checkpoint inhibitors, higher vinegar intake was linked to a better tumour response.
Fibre intake made no difference to response or survival.
What they found
Studies in people
Vinegar and response
Patients who responded to immunotherapy had higher vinegar intake than non-responders. In a statistical model, higher vinegar intake was independently linked to a better chance of response.
Vinegar and progression
Patients eating at least 0.05 g of acetic acid per day from vinegar had a median progression-free survival of 492 days, compared with 151 days in those eating less. This difference did not reach statistical significance.
Vinegar and overall survival
No significant difference in overall survival was seen between high and low vinegar intake groups. Median overall survival was 899 days versus 659 days.
Fibre and outcomes
Total dietary fibre, soluble fibre, insoluble fibre and fermentable fibre from grains showed no clear link to immunotherapy response or survival. Patients who responded had similar fibre intake to those who did not.
Other findings
Possible mechanisms
The authors suggest vinegar might affect the immune system through gut bacteria or through acetate absorbed into the blood. They note that most acetate from vinegar is absorbed before reaching the colon.
What the authors conclude
“The findings of this study imply that in Japanese patients undergoing ICI therapy, higher vinegar (acetic acid) intake may contribute to a better therapeutic response, whereas dietary fiber intake (at typical Japanese levels) appears to have a limited effect on outcomes.”
Also in their conclusions
- They conclude that higher vinegar intake may contribute to a better therapeutic response in Japanese patients on immunotherapy, while dietary fibre at typical Japanese levels appears to have limited effect.
- They advise that dietary recommendations for immunotherapy should not be one-size-fits-all but should consider regional habits and microbiota.
- They call for further prospective studies to confirm whether adding vinegar to the diet improves outcomes.
How it was done
The gut microbiome may affect how well immune checkpoint inhibitors work. Western studies suggested high fibre helps, but this had not been checked in Japanese people with different diets.
They followed 32 patients with advanced cancer at a Tokyo hospital from December 2021 to June 2024. Before starting immunotherapy, each patient filled in a food frequency questionnaire about the past year, covering 331 dietary items. Tumour response and survival were then tracked.
What it can’t tell you
- This was a small study of 32 people, so it cannot prove that vinegar causes better immunotherapy responses.
- Vinegar intake might be a marker for other diet or lifestyle factors, and the gut microbiome was not analysed.
- The food questionnaire relies on people's memory and gives approximate intake, not precise amounts.
Who paid
- Conflicts
- The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
- Authors work at
- Showa Medical University, Japan; Showa Medical University Hospital, Japan
The paper
- Title
- Vinegar intake in patients undergoing immune checkpoint inhibitor therapy: food frequency questionnaire study
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Licence
- CC BY. Words in quotation marks are the authors’; the rest is our summary.
- Cite
- Ariizumi H, Shimazui M, Ogawa C, et al (2025). Vinegar intake in patients undergoing immune checkpoint inhibitor therapy: food frequency questionnaire study. Frontiers in immunology. doi:10.3389/fimmu.2025.1640603Free full textPubMed 41459520DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error