Iron absorption from Southeast Asian diets

Abstract

Iron absorption from the whole diet was studied in 37 volunteers by employing the newly developed method of adding an extrinsic radioiron tracer to label the non-heme iron in the whole diet. Two radioiron isotopes were used, thus allowing comparisons in the same subjects. The reproducibility of the absorption measurements was good and there was also good agreement between measurements based on whole-body counting and on analyses of blood samples. The iron absorption from a meal of rice, vegetables, and spices containing almost 10 mg iron was only approximately 0.4% in normal subjects. When adding fruit or meat, or both, the absorption increased but to mean values still below 2% in normal subjects. In a few iron-deficient subjects, absorption figures up to nearly 10% were noted. The iron absorption in the normal subjects was much lower than the estimated requirement and also much lower than that found for other diets when we used the same method. No explanation of the low absorption has been found; the phytate content was not high, and the subjects had no malabsorption of an inorganic iron salt. The results may indicate that the present diets contain some hitherto unknown compounds(s) markedly inhibiting the absorption of non-heme iron from the diet. Other possibilities are also discussed.