The Biochemistry of Magnesium Deficiency*

Information concerning the minimum intake which will maintain the well being of the animal is an important item in the evaluation of the nutritional significance of a dietary component. As will be brought out below, a fixed value cannot be given for the minimum requirement of a given element. The amount required will be found to vary with varying conditions of the life history of the animal, and also in relation to the intake of other components of the diet. To obtain an estimate of the minimum magnesium requirement for the rat, we have attempted to determine the lowest magnesium level in the diet at which animals grow and reproduce normally and are maintained in a state of good health otherwise. In connection with this work it was found that the dietary calcium level has a very important effect in altering the minimum magnesium requirement. Certain data were already available which gave a clue to the amount of magnesium necessary to meet the needs of the rat dur-