UTILIZATION OF THE CALCIUM OF SPINACH

Abstract

Spinach, rich in minerals and vitamins, is one of the most widely used of leafy vegetables.It ranks high among the vegetables in calcium, but its calcium is less readily soluble than that of most other vegetables (1).However, calcium that is insoluble in cooking water may be rendered soluble in the stomach and upper intestine and thus be utilized.It seems probable that if this calcium is utilized that of other vegetables under the same conditions would be.Again, spinach contains an unusually high percentage of oxalic acid (2) which unlike most other organic acids of fruits and vegetables seems not to be oxidized in the body (3).Eaten in large quantities, free or combined, oxalates might possibly interfere with the assimilation of food, for cases of oxalic acid poisoning from food have been reported (4).For these reasons, it was planned to compare the calcium balance on a diet in which spinach furnished a very high proportion of the calcium with that of the same diet in which milk furnished an equal proportion of the calcium.Seven healthy women of the scientific staff of the Bureau of Home Economics acted as subjects.For 2 days previous to the experimental period and again after it until the marker in the feces appeared, the subjects ate varied diets estimated to have approximately the calcium content of the experimental period.A weighed simple mixed diet thought to contain all the body requirements and with the foods apportioned as nearly as possible like that recommended by Hunt in "Good Proportions in the Diet" (5) was eaten for 6 days.Milk furnished 79 per cent of the total calcium