The Availability of Calcium from Some Typical Foods

McClugage and Mendel (1) found the calcium of carrots and spinach to be poorly utilized by dogs. Rose (2), in calcium balance experiments with healthy young women whose intake was close to the estimated minimum for equilibrium, found the calcium of carrots almost as well utilized as that of milk, the carrots furnishing half or more of the total calcium of a mixed diet. Blatherwick and Long (3) likewise concluded that the calcium (as well as the phosphorus) of vegetables was satisfactorily utilized in meeting the maintenance requirements of healthy young women. They fed several vegetables-asparagus, cabbage, celery, lettuce, spinach, and summer squash-in the same experimental ration. Sherman and Hawley (4), studying the calcium balances of growing children, found that the retention of calcium was more variable but always less favorable when half of the milk of the diet was replaced by a carefully prepared mixture of vegetables (carrots and spinach with or without celery or string beans) which provided the same amount of calcium-the same total calcium intake. The calcium of this mixture of vegetables was clearly less well utilized than that of milk in these experiments with 3 to 13 year-old children. Rose and MacLeod (5) found that the calcium of almonds when constituting 73 per cent of the total calcium intake was well utilized; but when 85 per cent of the dietary calcium came from almonds the availability of the calcium appeared lower and much more variable. McLaughlin (6) compared the calcium balances of healthy women on a diet in which 73 per cent of the calcium was from spinach with one in which 79 per cent was from milk. Both diets furnished considerably more calcium than the average re-