Bioavailability of Magnesium and Potassium Salts Used as Potential Substitutes for Sodium Chloride in Human Nutrition - A Review.

Hypertension represents a major risk factor for cardiovascular diseases. As a diet high in sodium chloride is associated with hypertension, so-called "blood pressure salts" are attracting increasing scientific interest. These are characterized by a partial replacement of sodium chloride by other salts, mainly potassium and magnesium compounds. The aim of this review is to evaluate the bioavailability of potassium and magnesium salts as dietary supplements and to identify potential sodium chloride substitutes. A literature search was conducted in the PubMed database using the PICO scheme. Randomized controlled trials in healthy adults investigating the bioavailability of defined potassium/magnesium salts were included. Potassium chloride and potassium citrate showed good bioavailability irrespective of the route of administration and dose. Magnesium citrate and magnesium chloride showed good bioavailability while magnesium oxide was poorly bioavailable. This may be partly due to its poor solubility in water. The results indicate that potassium chloride and potassium citrate as well as magnesium citrate and chloride are suitable for the use as salt substitutes and for increasing potassium and magnesium intake in addition to reducing sodium. Due to its poor water solubility and consequently low bioavailability magnesium oxide is less suitable.