Hydrogen–water enhances 5-fluorouracil-induced inhibition of colon cancer
Runtuwene J, Amitani H, Amitani M, Asakawa A, Cheng KC, Inui A. · PeerJ. 2015;3:e859.
What kind of evidence is this?
Preclinical
Mouse Colon-26 tumour and cancer-cell experiment with 5-fluorouracil co-treatment
Cancer research
H₂-rich water
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Methods at a glance
Six-week-old female BALB/c mice bearing intraperitoneal Colon-26 tumours, plus Colon-26 and HepG2 cell cultures.
Tumour size/weight comparisons report n=7 per group; the article does not provide one consolidated animal total or clear group denominator for every survival curve. Cell assays were commonly triplicate.
Oral water every eight hours after tumour confirmation; weekly 5-fluorouracil, with tumour excision at day 10 and survival analyses extending beyond the treatment start.
High-content H₂ water or natural H₂ water given orally at 250 μL every eight hours, alone or with intraperitoneal 5-fluorouracil 100 mg/kg weekly.
H₂ dissolved in water — H₂ only, not Brown's gas and not inhalation.
High-content water was prepared at 0.4 MPa for 24 hours to approximately 0.8 mM; natural water contained 0.125 mM initially and approximately 0.1 mM during monitoring.
Not applicable — oral H₂-rich water; preparation flow was not reported.
No O₂ was co-delivered as part of the intervention.
Milli-Q water, high- and low-content H₂ water, 5-fluorouracil alone and the corresponding combination groups; HepG2 served as a second cell-line comparison.
Outcomes and reported result
Mouse survival, tumour size/weight, water/food intake and body weight, cell viability/apoptosis, p-AMPK, AIF, caspase-3 and chemical radical-scavenging assays.
The 5-fluorouracil combinations, especially high-content H₂ water, favored survival and tumour measures. H₂ water alone showed only a trend in survival and did not improve body-mass recovery. H₂ did not significantly reduce HepG2 viability, showing the reported cell effect was not general across both lines.
The complete free PMC article, figures and methods were checked for water concentrations/dose, co-treatment, outcome-specific samples, positive and null results, stated limitation, commercial supply/funding and disclosures.
A reported association, difference or mechanism is not automatically a clinical benefit. Null findings, outcome type, study design and precision all matter.
Cautions and applicability
Small mouse groups with incomplete consolidated allocation reporting, one primary tumour model, combined intervention cannot isolate all H₂ effects, many cell/molecular endpoints and no toxicity assessment comparable with clinical chemotherapy. VanaH supplied natural H₂ water and partly funded the project; authors stated the funder had no role in design, analysis or publication.
Colon-26 tumour-bearing mice and two cell lines; it does not establish efficacy or safety with fluorouracil in people with colorectal cancer.
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No single-study GRADE certainty rating is assigned. Certainty is assessed by important outcome across a complete eligible evidence set, not by attaching a final grade to one source.
Sources and record status
PMID: 25870767 · DOI: 10.7717/peerj.859
Free full article in PubMed Central.
Complete PMC article and PubMed metadata; full-text extraction checked 9 August 2026.
2026-08-10