Effect of vitamin B-6 on plasma and red blood cell magnesium levels in premenopausal women.

The effect of 100 mg of vitamin B6 twice a day on plasma and red blood cell (RBC) magnesium was evaluated in nine premenopausal subjects during the period of one month. According to reported normal ranges for plasma and RBC magnesium (1.7 to 2.3 and 4.7 to 7.0, mg per dl, respectively), three subjects had low plasma magnesium, and all subjects had low RBC magnesium during the control period. Following vitamin B6 administration, the mean plasma and RBC magnesium levels were significantly elevated, with a doubling of RBC levels after four weeks of therapy. These results support the postulate that vitamin B6 plays a fundamental role in the active transport of minerals across cell membranes.