Availability of Iron in Wheat

Abstract

Elvehjem, Hart, and Sherman 1 have reported that the inorganic iron content of wheat is approximately 47% of the total iron content. Their biological studies indicated that this figure also represents the available iron content. On the contrary Rose, Vahlteich, and MacLeod 2 observed that wheat is an excellent source of iron for hemoglobin formation.

In order to determine whether there is any great variation in the form of iron in different varieties of wheat, 11 samples representing both hard spring wheat and soft winter wheat were analyzed for total and inorganic iron. A modification of the technic of Elvehjem, Hart, and Sherman, 1 which employs a longer extraction period, was used to determine the inorganic iron, whereas the total iron was determined on ashed samples by the thioglycolic acid method. 3 The total iron of the 11 samples ranged from 2.90 mg. to 4.87 mg. of iron per 100 gm. of wheat. The inorganic iron showed about the same amount of variation, the range being from 2.46 mg. to 4.04 mg. of iron per 100 gm. of wheat. The percentage of inorganic iron with respect to the total iron varied from 73% to 88%, the average being 81%. This figure agrees fairly well with the value suggested by Shackleton and McCance. 4

Two of the samples of wheat were also used for a biological assay. Albino rats were made anemic by employing an exclusive milk diet. As soon as values below 4.0 gm. of hemoglobin per 100 cc. of blood were attained, the experimental diets were started. Three groups of experimental animals received 0.25 mg. of iron per day. One group of 5 animals received 0.25 mg. of iron per day furnished by FeCl₃; a second group of 6 animals received Trumbull wheat (soft winter wheat) in quantities to supply the same amount of iron per day; and the third group of 6 animals received Nabob wheat (soft winter wheat) in quantities to supply 0.25 mg. of iron per day.