Dietary phosphate supplementation delays the onset of iron deficiency anemia and affects iron status in rats

Inorganic phosphate (Pi) plays critical roles in bone metabolism and is an essential component of 2,3-diphosphoglycerate (2,3-DPG). It has been reported that animals fed a low-iron diet modulate Pi metabolism, whereas the effect of dietary Pi on iron metabolism, particularly in iron deficiency anemia (IDA), is not fully understood. In this study, we hypothesized the presence of a link between Pi and iron metabolism and tested the hypothesis by investigating the effects of dietary Pi on iron status and IDA. Wistar rats aged 4 weeks were randomly assigned to 1 of 4 experimental dietary groups: normal iron content (Con Fe) + 0.5% Pi, low-iron (Low Fe) + 0.5% Pi, Con Fe + 1.5% Pi, and Low Fe + 1.5% Pi. Rats fed the 1.5% Pi diet for 14 days, but not for 28 days, maintained their anemia state and plasma erythropoietin concentrations within the reference range, even under conditions of low iron. In addition, plasma concentrations of 2,3-DPG were significantly increased by the 1.5% Pi diets and were positively correlated with plasma Pi concentration (r = 0.779; P < .001). Dietary Pi regulated the messenger RNA expression of iron-regulated genes, including divalent metal transporter 1, duodenal cytochrome B, and hepcidin. Furthermore, iron concentration in liver tissues was increased by the 1.5% Pi in Con Fe diet. These results suggest that dietary Pi supplementation delays the onset of IDA and increases plasma 2,3- DPG concentration, followed by modulation of the expression of iron-regulated genes.

内容要旨・審査要旨・論文本文の公開:
内容要旨・審査要旨 : LID201606151005.pdf
論文本文 : LID201612081001.pdf
著者の申請により要約(2016-06-15公開)に替えて論文本文を公開(2016-12-08)
本論文は, 著者Mari Nakaoの学位論文として提出され, 学位審査・授与の対象となっている。