| Sodium iron (III) ethylenediaminetetraacetate(NaFeEDTA)is a new type of chelating iron fortificant. It attracts great attention in recent years because of it's remarkable impact on iron deficiency anemia (IDA). NaFeEDTA has been applied in IDA intervention projects in several countries in past decades, thus it was recommended by the approval of Joint FAO/WHO Expert Committee on Food Additives (JECFA) in 1993. As a food fortificant, NaFeEDTA has many advantages compared with other iron fortificants such as less ferruginous taste, no detectable side effects on intestines and stomach, less influence to iron absorption inhibitors, less adverse effects on sensory, physical and chemical properties of food vehicles and high bioavailability etc. NaFeEDTA is believed a better iron source for control and prevention of ID and IDA in terms of food fortificant.As an iron fortificant, the bioavailability of NaFeEDTA is two or three times higer than other iron fortificants such as ferrous sulfate. Although it has shown remarkable achievements on the IDA control and prevention, the mechamism of NaFeEDTA absorption in the organism gastrointestinal tract has not been illuminated clearly. In this study, three methods such as in vitro stomach and intestine model, dialysis bag model and everted intestinal sac model were used to observe the possible mechanism of NaFeEDTA absorption systematically.The results of the in vitro model indicate that NaFeEDTA was stable under different pH conditions from 2 to 7.5. That NaFeEDTA did not show any changes in the artificial gastrointestinal juice suggests that enzymes such as pepsin and pancreatin have no effects on NaFeEDTA. When oxalic acid and phytate was added to the artificial gastrointestinal juice at molar ratios of iron/ oxalic acid and iron/phytate as 1:1, 1:3, 1:5 and 1:8, NaFeEDTA was also stable and remained its chelate form. It indicates that oxalic acid and phytate could loot ferric iron ion from NaFeEDTA. It can be speculated from these results that NaFeEDTA had high stability in the organism gastrointestinal tract.Dialysis bag model test showed that the contents of NaFeEDTA in the dialysis bag were correlated with infiltration time. The concentration of NaFeEDTA in the dialysis bag was 61 percent that of outside the dialysis bag after 2 hours infiltration, 84 percent for 4 hours, 94 percent for 6 hours and almost reached equilibrium after 8 hours. It shows that NaFeEDTA existed as an intact complex in the artificial gastrointestinal juice and it might penetrate through the dialysis bag in an intact form. These results supposed thatNaFeEDTA could be absorbed intact by the small intestine mucous membrane.The everted intestine sac model was used to investigate how the mucosal absorptive cells of different intestinal segments intake NaFeEDTA by using in vitro incubation of duodenum, jejunum and ileum everted intestine sac of rats. The results showed that after incubation of everted intestine sac of duodenum, jejunum and ileum in the mucous membrane side solution for some time, NaFeEDTA was detected in the serous membrane side solution and the contents was increased with the incubation time. It indicates that NaFeEDTA could be uptaked intact by the epithelium absorptive cells. The comparision of the concentration of total iron and NaFeEDTA showed that there was little difference between the two quantums. The total iron content was equal to iron content of NaFeEDTA so that it should be considered that NaFeEDTA was fully uptaked in an intact form. Comparation among the three different intestinal segments showed that the content of NaFeEDTA in the jejunum sac was higer than that of duodenum and ileum was higer than that of jejunum. Ileum is more effective to uptake NaFeEDTA. When adding oxalic acid and phytate to the incubation solution, there is little difference in the NaFeEDTA contents. It suggests that oxalic acid and phytate may have no influence on the uptake of NaFeEDTA by small intestine epithelium absorptive cells.
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