The Effect of Phytate and other Food Factors on Iron Absorption

Abstract

The effect of 7 test meals upon the absorption of either reduced Fe⁵⁵ or reduced Fe⁵⁹ fed to adolescent boys was measured. The test meals consisted of (I, VI) milk, rolled oats, tomato juice, white bread and omelet; (II) milk; (III) milk and sodium phytate; (IV, VII) milk and rolled oats; and (V) water. Each meal contained approximately the same amount of iron. Meals I, VI and VII contained the same level of natural phytate in rolled oats; meal III contained the same quantity of phytate, as the sodium salt; meal IV contained approximately half as much rolled oats and phytate as meal VII; phytate was absent from meals II and V. The following percentages of radioactive iron were absorbed from these meals: 4.43, 17.4, 1.74, 9.81, 26.9, 5.76 and 8.84. Milk reduced the absorption of iron by one-third. This was not due to the action of phytates, for the milk contained none. Rolled oats and milk reduced the absorption of iron by two-thirds. Thus, rolled oats interfered no more than did milk. There was no correlation between the phytate content of rolled oats and the reduction in iron absorption. Sodium phytate reduced the absorption of iron by 15-fold, indicating that added soluble phytates can interfere with iron absorption. The absorption of iron from the breakfast was one-fifth that from the water meal. Medicinal iron should be more effective if administered between meals. Evidence is presented for the inverse correlation of iron absorption with the solids content of the test meals.