Background: It was reported that vanadium compounds possess insulin-like activity,
although suitable vanadium compounds have not yet developed as anti-diabetes mellitus drugs.
Objective: As Mt. Fuji subsoil water contains high levels of vanadium, this study aimed to
assess whether it showed insulin-like effects.
Method: Insulin-like effects of vanadium ions have been investigated in cultured cells, using
rat fibroblasts (Py-3Y1-S2), human esophageal cancer cells (TE-13), and other established cell
lines. To evaluate insulin-like effects, glucose consumption in the cultured media and cell
growth based on cellular protein content were measured, and cytotoxic effects on cells were assessed.
Results: The vanadium concentration in the commercially available Mt. Fuji subsoil water
ranged from 56–144 ppb, and the highest concentration (144.2 ± 1.2 ppb) was observed in
Healthy Vana Water. The vanadium concentration in other water samples derived from
wells, ravine rivers, and cities ranged from 0.5 to 27 ppb, and a comparatively high vanadium
concentration (27.1 ± 0.0 ppb) was observed in the well water at Kayayama-Machi,
which is close to Mt. Fuji. The largest insulin-like effect on glucose consumption was observed
in Healthy Vana Water among the various water samples tested. The effects of vanadium
at low concentrations of 200-500 µg/l seemed to accelerate cell growth, while high
concentrations of vanadium (> 500 µg/l) had a cytotoxic effect.
Conclusion: Mt. Fuji subsoil water possesses higher insulin-like activity than other water
samples derived from wells, ravine rivers, and cities, suggesting a potential future role in
diabetes mellitus therapy.