MAGNESIUM SUPPLEMENTATION FOR 30 DAYS LEADS TO CORRELATIVE CHANGES INCIRCULATING IONIZED MAGNESIUM AND PARATHORMONE (IPTH)

9 healthy probands were supplemented with 316 mmol magnesium (Asta Med ica) per day for 30 days. Blood samples were collected at day 0, 5, 10 , 20 and 30. iPTH, total and ionized magnesium were measured and bound magnesium was calculated as the difference from total to ionized magn esium. It turned out, that total magnesium levels did not change throu ghout the whole time of the experiment, while ionized magnesium decrea sed during the first 10 days and bound magnesium tended to increase. I onized magnesium and not calcium was positively correlated with iPTH t hroughout the experiment. There were also correlations within the grou ps at the different sampling times. On day 0 calcium (barely) and ioni zed magnesium (nicely) correlated with iPTH levels. Both the correlati ons vanished after the begin of magnesium supplementation, the one wit h calcium for good, but the correlation with ionized magnesium and iPT H became significant again at day 20 and 30, when the absolute levels of ionized magnesium did increase again. If this correlative behaviour of iPTH and ionized magnesium above a certain minimal level of ionize d magnesium proves to be true in general, then the paradox decrease of ionized magnesium in the first stages of magnesium supplementation ma kes sense. By keeping the levels of iPTH down, it ensures that supplem ented magnesium does enter the bone and is not liberated along with ca lcium by possibly increased iPTH levels, triggered by high circulating magnesium concentrations.