The Iron Requirement of the Normal Human Adult

Abstract

A healthy male, 26 years of age, carried on his usual duties as a graduate student for 316 days on a diet whose average daily iron content was 4.9 mg. During the last 31 days of this period the subject was in iron balance when the diet contained 5.2 mg. of iron daily. The blood hemoglobin, blood iron and red blood cell levels were within normal limits. Two other male subjects were likewise in iron balance after 4 and 5 months on diets containing 7.1 and 7.8 mg. of iron daily respectively, and their blood contained normal amounts of hemoglobin and red blood cells. A young woman living for over a month on a diet containing 9.1 mg. of iron daily was in iron balance during the intermenstrual phase. The total menstrual blood loss represented 33 cc. of the subject's blood. Normal urinary iron amounts to about 0.02 mg. per 100 cc. of urine. These observations, together with those in the previous literature, indicate that the iron requirement of the normal adult male is not more than 5 mg. daily. The obvious importance of the availability of iron in the diet has only recently been demonstrated.