Introduction:
The proposed benefits of alkaline water generally lack experimental supporting evidence.

Material and methods:
We tested the effects of alkaline water on tumor development in C57BL/6 mice. To recapitulate early tumor development, mice were fed a high-fat diet and treated with DEN (50 µg/l) and TCPOBOP (0.5 µg/g) for 24 weeks.

Results:
Cell proliferation was significantly lower in animals receiving alkaline water, and VEGFR2 staining was higher in the vasculature, suggesting less advanced disease stages. B16-V5 cells were injected subcutaneously or through the tail vein to generate primary tumors or lung metastatic nodules, respectively. Subcutaneous tumors of mice exposed to alkaline water showed a lower proliferative index and vasculature with a better-preserved intima layer and structure. The number of lung metastatic nodules was lower in mice exposed to filtered water. The vascular effects were tested in a rat model of hypertension (spontaneously hypertensive rat – SHR). Following 12 weeks of alkaline water consumption, the aortic rings had an enhanced vasodilatory response to a nitric oxide donor (nitroprusside – NTP), and several inflammatory markers were reduced in blood and heart tissue.

Conclusions:
These results indicate that alkaline water could have a protective effect on vascular function, reduce inflammation, and in the context of tumor development, reduce the incidence of metastasis.