Insulin-like Effects of Mt. Fuji Subsoil Water which Conta ins Vanadium on Cultured Cells: Insight from Japan

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.