Gamma Aminobutyric Acid Increases Absorption of Glycine-Bound Iron in Mice with Iron Deficiency Anemia

Iron deficiency is a leading cause of anemia. Amino acids are known to promote the absorption of both soluble and insoluble iron. The bioavailability of organic iron is higher than that of inorganic iron. Therefore, the aim of this study was to evaluate the iron absorption of glycine-bound iron (an organic iron) and a combination of glycine-bound iron and gamma aminobutyric acid (GABA) in mice with iron deficiency anemia (IDA). Mice were fed an iron-deficient diet for 3 weeks, followed by oral administration of GABA, inorganic iron, glycine-bound iron, or GABA plus glycine-bound iron for 5 weeks. Ferritin storage in the spleen was measure by immunohistochemistry (IHC). Iron deposition in the liver and spleen tissues was analyzed using atomic absorption spectrometry. Expression levels of iron absorption-related genes were measured by quantitative real-time polymerase chain reaction (qPCR). Iron absorption was enhanced in the glycine-bound iron-treated group compared with the inorganic iron-treated group. Hemoglobin, serum Fe, ferritin, and liver iron levels did not increase in mice treated with GABA alone. However, mice administered GABA in combination with glycine-bound iron showed higher iron absorption than those administered organic iron alone. Our results indicate that glycine-bound iron in combination with GABA might exert a synergistic effect on iron absorption and bioavailability, suggesting that the addition of GABA to existing iron supplements might increase their effectiveness for treating IDA.