The intestinal absorption of59Fe which was incorporated into rabbit hemoglobin, muscle and liver by biosynthesis was measured with the59Fe-absorption-whole body-retention test in human subjects with normal iron stores and individuals with prelatent/latent iron deficiency using an oral test dose of 10 μMol (≙0.558 mg)59Fe. Persons with normal iron stores absorbed 23.3±10.2 {Mathematical expression} % of59Fe++ and 20.1 ± 10.3% of the hemoglobin59Fe (p>0.10). The absorption of59Fe++ was increased to 81.1±18.2% (=348% of control group, p<0.001) in prelatent/latent iron deficiency whereas the absorption of hemoglobin-59Fe was augmented only to 30.2±13.1% (=150% of control group;p<0.005). In persons with normal iron stores muscle-59Fe and liver-59Fe is less available than hemoglobin-59Fe, since an absorption of only 12.3±3.9% (p<0.05) and 13.2±5.4% (p<0.02) was observed for muscle-59Fe and liver-59Fe resp. Prelatent/latent iron deficiency caused an increase of the absorption of muscle-59Fe to 23.5±8.5% (=191% of normal control group;p<0.005) and an increase of the absorbability of liver-59Fe to 25.7±6.0 (=195% of normal control group;p<0.001), so that there is no more significant difference between the absorption of hemoglobin-59Fe, muscle-59Fe and liver-59Fe in persons with prelatent/latent iron deficiency (p<0.20 and <0.40 resp.). The amount of dietary muscle-Fe, liver-Fe or hemoglobin-Fe required for covering the daily whole body iron turnover (=requirement) of 1.03-1.37 mg for men and 0.99-1.39 mg in females was calculated from the measured absorbability of muscle-, liver- and hemoglobin-iron. The calculation resulted in daily uptake requirements of 3657-5133 g muscle or 328 to 461 g liver which are completely unrealistic both from an economical and a dietary point of view. The calculated amount of 3.5 to 4.8 g of hemoglobin/day however could be a reasonable basis for a dietary prophylaxis of iron deficiency. Nevertheless a well-absorbable and tolerated oral iron preparation seems to be the best solution to the world-wide problem of necessary iron prophylaxis and therapy. © 1969 Springer-Verlag.
