Comparative study of the effects of different iron sources on bioavailability and gastrointestinal tolerability in iron-deficient rats

Iron deficiency anaemia is a global health issue affecting millions of people. Though effective, conventional iron sources used for supplementation often cause gastrointestinal side effects. This preclinical study evaluated the efficacy and tolerability of three iron supplements—ferrous bisglycinate, LIPOFER™ microcapsules (Def-LFe1), and a commercially available microencapsulated iron pyrophosphate (Def-Fe2)—in reversing diet-induced iron deficiency in rats compared to FeSO 4 . The study included three phases: (a) First, animals underwent a 24-day iron depletion period; (b) then, animals were exposed to a 21-day repletion period, receiving treatments at a human-equivalent dose of 80 mg of elemental iron; and (c) finally, to evaluate gastrointestinal tolerability, animals were supplemented with each treatment for 9 weeks. All supplements reversed iron deficiency within 14 days without adverse gastrointestinal effects. However, based on the decrease in TIBC and transferrin levels, coupled with the higher haemoglobin levels, Def-LFe1 demonstrated a higher absorption rate than Def-Fe2. In addition, the group supplemented with LIPOFER™ showed higher feed efficiency, especially compared to the control and FeSO 4 groups. FeSO 4 increased IL-6 gene expression in the colon, while Def-LFe1 did not. These findings highlight LIPOFER™ as a promising alternative to conventional iron supplementation. Further studies should be conducted to clarify these issues.