Hypertension induction in Dahl rats.

There is experimental and epidemiologic evidence that some minerals and trace elements play a role in hypertension. We designed an experiment in which salt and water sources were manipulated to examine the possible impact of this relationship. A strain of rats (Dahl rats) known to become hypertensive with sodium chloride ingestion was used to study the effect of salt source and water source on the induction of hypertension. The group on tap water and table salt had blood pressures (184 mmHg +/- 19) significantly higher than every other group in the experiment. The experimental animals receiving tap water plus table salt had the highest blood pressure levels, although they consumed the lowest quantity of sodium. Analysis of the tap water samples showed "soft water" by analysis of calcium and magnesium concentration. This could adversely affect blood pressure. The relatively high magnesium concentration in sun evaporated sea salt may play a protective role in hypertension induction. The zinc and copper present in tap water may play an exacerbating role.