The general characteristics of the subjects are presented in . The average age of the subjects was 32.5 years. The subjects reported a relatively high level of education; 19.4% and 53.5% had completed college and university, respectively and 15.2% had completed graduate school. And 35.6% had their average monthly household incomes of 300,000-450,000 won.
General characteristics of the subjects*
Among the subjects, 25.5% did not take any supplements (N), 12.7% used single nutrient supplements for iron or folic acid (S), 38.2% used multi-vitamins containing folic acid and iron (M), and 23.6% used both single nutrient and multi-vitamins containing folic acid and iron (S+M). While 73.3% took a supplement containing iron, 66.7% took a supplement containing folic acid.
shows mean daily intakes of iron and folate from food and dietary supplements. The mean intake of iron from food was 11.1 mg, which is 46.3% of the RNI for pregnant women. The iron intakes in the M or S+M group were significantly lower than that in the S group. The average daily intake from supplements was 66.8 mg. The average intake of iron of 19 women consumed iron in S group was 37.5 mg, whereas the mean intakes in the M and S+M group were 56.2 mg and 98.1 mg, respectively. The intake in the S+M group was highest, followed by the M and S groups. These differences were statistically significant. The total daily intakes of iron from food and supplements were 11.9 mg in the N group, 49.1 mg in the S group, and 66.2 mg in the M group, and 108.1 mg in the S+M group, which showed significant differences between the groups. The average iron intakes of the S, M, S+M groups were higher than the RNI of iron, even though the intake of the N group was lower.
Intakes of iron and folate from food and supplements*
The average daily intake of folate from food was 231.2 µg, which only accounted for 38.5% of the RNI of pregnant women. Similar to iron, the intake of S+M group was significantly lower than the intake of S group. The average intake of 8 women consumed folate in S group was 612.5 µg. The average intakes of the M and S+M groups were 773.0 µg and 946.2 µg, respectively. The intake of the S+M group was significantly higher than the S and M groups alone. The total intake of folate from food and supplements was calculated as the Dietary Folate Equivalent (DFE) in order to account for the absorption efficacy. The intake was highest in the S+M group with 1,811 µgDFE. The intake was lower in the order of M, S, and N group. Significant differences were observed between the groups. While the average intake of the N group was 253.2 µgDFE, which was lower than the RNI, the S, M, and S+M groups that consumed the supplements had more than the RNIs.
shows the distribution of pregnant women who consumed iron and folate less than EAR or more than UL. The proportion of pregnant women who consumed less than EAR was 85.7% in the N group. However, only 9.5% in the S group, 4.8% in the M group, and no one in the S+M group. On the other hand, although the proportion of subjects who consumed more than UL of iron was nonexistent in the N group, the proportion was very high among the supplement users (S group - 81.0%, M group - 88.9%, S+M group - 97.4%). Significant differences existed in the distribution of subjects classified based on the UL according to the type of supplements.
Distribution of the subjects who consumed iron and folate from food and supplements less than EAR or more than UL*
The proportion of pregnant women who consumed less than EAR of folic acid was 95.2% in the N group, 61.9% in S group and 0% in M group and S+M group presenting significant differences according to the supplement type. In case of the S group, most subjects consumed the single iron supplement and only 8 subjects consumed folic acid. This is related to the fact that 61.9% of subjects who did not consume folic acid supplements had less than EAR. The UL of folic acid was set as 1,000 µg consumed in supplement form [5
]. Although no pregnant women consumed more than UL in the N group, significant differences were observed in the other groups (4.8%, 1.6% and 25.6% in the S, M, and S+M groups, respectively).
presents the hematologic indices according to the type of supplements of pregnant women. The average hemoglobin concentration was 11.9 g/dL in the N and S group and 12.4 g/dL and 12.3 g/dL in the M and S+M groups, respectively. The hemoglobin concentration of the M group was significantly higher than the N group. Furthermore, the hematocrits were 35.0% and 35.4% in the N and S group respectively, which were lower than those in the M and S+M groups. The hematocrit of the M group was significantly higher than the N group. MCV, MCH, MCHC did not show any significant differences between the groups and the average values were all in the normal range except for MCH of the S group. However, the average values of RBC counts were lower than the normal ranges in all groups.
Hematologic indices of the subjects*
shows the distribution of pregnant women diagnosed as anemia according to hematologic indices based on the type of supplements. 7.9% of the subjects had hemoglobin concentration below 11 g/dL (16.1% in the N group, 17.6% in the S group, 1.8% in the M group and 5.9% in the S+M group). 10.1% of subjects had hematocit less than 33%. The possible folate deficiency exists in one subjects in the N group presenting with MCV above 100 fL. The proportions of pregnant mothers diagnosed as anemia according to the hematologic indicators in the N or S group was higher than in the M or S+M group. As the frequencies in the distribution of subjects diagnosed as anemia were too low for testing the significant differences, χ2-test was performed between the N group and the combined group of the S, M and S+M groups as well as between the combined groups of N and S groups and the combined groups of M and S+M groups. There were significant differences between the combined groups (p < 0.01).
Distribution of the subjects by anemic cutpoints*
presents the correlation between hematologic indices and the intake of iron and folate. The concentrations of hemoglobin and hematocrit were significantly correlated with the intake of iron and folate from supplements as well as the total intakes. However, there was no correlation with the dietary intakes of iron and folate. Although dietary intake of iron showed a significant inverse correlation with MCH, it was difficult to explain the reason.
Correlation of intakes of iron and folate from food and supplements with hematological indices*