The Requirement of Magnesium by the Normal Adult. Summary and Analysis of Published Data.

I T IS hoped that Perspectives in Nutrition will review the literature selectively, interpret it moderately and present a spectrum of ideas that will serve as a continual stimulation to nutritional research applied to medical problems. M AGNESIUM has been accepted as an essential nutrient for the rat since 1932 when Kruse, Orent and McCollum 1 induced an acute magnesium deficiency syndrome in rats. The characteristics of magnesium deficiency were then studied in rats and in other laboratory animals by these investigators, 2-e and byGreenberg,T-10 Tuftsetal.u · 12 and Watchorn and McCance. u ·In the past fifteen to twenty years, the early work on the magnesium deficiency syndrome has been verified and interrelationships of magnesium with other dietary · factors have been elucidated. The systems affected in the acute deficiency state are primarily neuromuscular, cardiovascular and re-nal. Hyperirritability terminating in convulsions , hyperemia, vasodilation and trophic changes in the skin are initial manifestations of acute magnesium deficiency. Calcinosis of heart, muscle and kidney occur later. During the 1930's and early in the war years, there was a fliiriy of interest in the possibility that magnesium depletion might play a role, in both man and farm animals, in conditions characterized by convulsions or by less severe manifestations of neuromuscular irritability. Haury and Hirschfelderu-18 correlated low plasma levels of magnesium with several clini-342 cal conditions in which hyperirritability or convulsions are presenting signs, amongst which were epilepsy, eclampsia and renal in-sufficiency, as well as several patholog1c states Ui"wwcli· such signs are absent. Grass staggers of cattle, and the convulsions of calves fed only whole nillk, were similarly found to be associated with low blood magnesium levels, and to be preventable by feeding magnesium supplements.u-22 Autopsy examination of the cows and calves that died in acute magnesium d~ijciency rev~ed severe-cardiovascular damage, including necrosis and calcification.-C~ntinuing biochemical investigations have established the importance of magnesium as a cofactor in enzymatic reactions of carbohydrate , protein and energy metabolism. Phys-iologic studies have demonstrated its participation in neuromuscular conduction, in protein synthesis and in maintenance of cellular integrity. Thete are several excellent review articles on the multiple roles of magnesium in the body economy. u-u Despite laboratory substantiation of the indispensability of magnesium, published articles indicating clinical interest in this cation were few until late in the 1950's. Martin and her co-workers, and McCollister and Flink and their colleagues, who have continued to contribute to the understanding …