Calcium Involvement in Magnesium Deficiency. ∗

The existence of an intimate relationship between the metabolism of calcium and magnesium in the animal body has long been postulated. In harmony with this hypothesis the writers have accumulated considerable evidence which points to a calcium involvement in the syndrome of magnesium deficiency.

Certain aspects of such an involvement have already been pointed out by Kruse, Schmidt and McCollum 1 and by Orent, Kruse and McCollum 2 who observed that animals reared on a magnesium deficient diet showed a marked retention of calcium and an abnormally high percentage content of calcium in their bones.

The phases of the involvement observed by the writers are that there is an accumulation of calcium in the viscera of the body, particularly in the kidneys, and that the magnesium level of the diet at which deficiency symptoms appear is controlled by the dietary level of calcium.

A greater amount of magnesium is required to prevent the development of deficiency symptoms as the calcium of the diet is increased. This is illustrated by the performance of rats reared on diets containing the mineral composition given in Table I.

The animals reared on the high calcium diet developed all the features common to magnesium deprivation such as hyperemia, hyperirritability, and cachexia. A large percentage of these animals died from convulsive seizures. Those that survived developed a greasy unkempt appearance, became emaciated, and in other ways showed signs of malnutrition. At the same magnesium level, the rats on the low calcium diet were maintained in a normal state of health and vigor. The females that were bred went through a successful gestation period and gave birth to young of normal weight.

The accumulation of calcium in the viscera of the body of magnesium deficient rats is shown in Table II.