The Iron Requirement of Six Adolescent Girls

Abstract

Six girls, 13 and 14 years of age, all of whom had passed the menarche, were fed a controlled diet for 9 weeks. Two levels of iron were fed in two consecutive 4-week periods preceded by an adjustment period of one week. During the first 4-week period the average intake was 8.6 mg of iron per day, and during the second period the intake was raised to 11.7 mg daily. The iron required by the 6 subjects was estimated by adding together the amount needed to replace menstrual losses as determined by analysis and the amount needed for growth based on the estimates of Health and Patek ('37). The minimum required retentions were 0.62, 0.64, 0.75, 0.96, 1.13 and 1.89 mg per day, or an average of 1.00 mg per day. On an intake of approximately 8.6 mg per day, retentions for the 6 girls were 0.80, 0.86, 1.22, 1.23, 1.42 and 1.54 mg per day, or an average of 1.18 mg daily. Five of the 6 retentions on this intake were larger than the probable minimum required retentions; the retention of one subject was inadequate. On an intake of approximately 11.7 mg per day, retentions for the 6 girls were 0.33, 1.15, 1.54, 1.76, 2.10 and 2.22 mg per day, or an average of 1.52 mg daily. On the higher dietary intake the retentions of the subjects were larger than the minimum required retentions, with a wide margin of safety, except for one subject, whose retention appeared to be atypical On the basis of the 6 cases in this study, a dietary intake of 12 to 13 mg per day is recommended for girls of this age until more cases have been studied. The allowance of 15 mg per day recommended by the National Research Council ('48), which had to be made without experimental evidence as a basis, is probably higher than necessary.