Dietary Folate Intake, Blood Folate Status, and Urinary Folate Catabolite Excretion in Korean Women of Childbearing Age

Abstract

This study assessed folate intake, folate concentrations in plasma and erythrocytes, plasma total homocysteine (tHcy) concentrations, and urinary excretion of folate metabolites in Korean women of childbearing age. A total of 36 women voluntarily participated in this study. Precise dietary intake for 3 consecutive days was determined by weighing all foods consumed, and folate intake was calculated with a computer-aided dietary analysis system. Folate concentrations in plasma and erythrocytes were determined via microbiological methods and in plasma by HPLC. Urine excreted over the same period of time was collected and assayed for folate catabolites, para-aminobenzoylglutamate (pABG) and para-acetamidobenzoylglutamate (ApABG) by reverse-phase HPLC after affinity chromatography. The mean folate intake was 206.9+/-90.8 microg DFE/d, and the mean concentrations in plasma and erythrocytes were 10.5+/-3.7 and 249.9+/-77.8 ng/mL, respectively. Erythrocyte folate concentration was low in 2.8% of the subjects (<140 ng/mL) and was marginal in 5.5% (140-156 ng/mL). The mean plasma tHcy concentration was 12.7+/-0.2 nmol/mL, and 11% of the subjects evidenced hyperhomocysteinemia (>or=15 nmol/mL). The mean urinary excretion levels of pABG and ApABG were 10.7+/-3.8 and 89.1+/-19.5 nmol/d, respectively. The means of folate reserve and folate turnover rate were 26.2+/-11.6 and 10.5+/-3.9, respectively. We noted positive relationships between folate intake and the folate concentrations in plasma and erythrocytes, as well as the urinary excretions of ApABG and total folate catabolites. In addition, the erythrocytic folate concentrations were positively associated with the urinary excretions of ApABG and total folate catabolites. In conclusion, the folate status of Korean women of childbearing age was marginally deficient with inadequate concentrations of erythrocyte folate and elevated plasma tHcy, largely due to insufficient folate intake. The marginally deficient folate status was confirmed by the low excretion of folate catabolites in urine.