[Comparative study of magnesium salts bioavailability in rats fed a magnesium-deficient diet]

The purpose of this study was to compare efficiency of compensation of alimentary Mg deficiency after administration of 12 organic and 8 inorganic magnesium salts and to evaluate the ability of vitamin B6 to accelerate their effect. Two hundred eighty rats were placed on a Mg-deficient diet (Mg content (15 mg/kg) and demineralized water for 7 weeks. Twelve control rats were fed a basal diet (Mg content 500 mg/kg). Starting from day 49 of the Mg-deficient diet, the rats were given magnesium salts (50 mg magnesium and 5 mg pyridoxine per kg): Mg chloride, Mg sulphate, Mg oxide, M nitrate, Mg thiosulphate, Mg hydrophosphate, Mg carbonate, Mg trisilicate, Mg (L-, D- and DL-) aspartate, Mg (L- and DL-) pyroglutamate, Mg succinate, Mg glycinate, Mg orotate, Mg taurate, Mg lactate or their combination with vitamin B6 (5 mg/kg b.w.). Erythrocyte and plasma Mg levels were measured by spectrophotometry following the colour reaction between Mg and titanium yellow. Mg L-aspartate compensated for magnesium deficit more effectively and faster than all other salts. Mg chloride showed the highest efficiency among inorganic magnesium salts. Both Mg chloride and Mg L-aspartate in combination with vitamin B6 caused statistically significant compensation of magnesium deficit.