vestigators converted the quantity of urinary catabolites to urinary folate equivalents and estimated that the recommended folate intake for second-trimester pregnant women would be 660 µg/day.

From these data, low dietary folate intake plus 100 µg of supplemental folate (equivalent to approximately 200 µg/day of DFEs) is inadequate to maintain normal folate status in a significant percentage of population groups assessed. The EAR therefore was derived by adding this quantity in DFEs (200 µg/day) to the EAR for nonpregnant women (320 µg/day) to provide an EAR of 520 µg/day of DFEs.

The RDA for folate is set by assuming a coefficient of variation (CV) of 10 percent (see Chapter 1) because information is not available on the standard deviation of the requirement for folate; the RDA is defined as equal to the EAR plus twice the CV to cover the needs of 97 to 98 percent of the individuals in the group (therefore, for folate the RDA is 120 percent of the EAR). Data from the controlled metabolic study support an RDA of 600 µg/day of DFEs based on maintenance of normal erythrocyte folate concentrations and agree with the findings from the series of population studies that 600 µg/day of DFEs is adequate to maintain normal folate status in groups of pregnant women.

The EAR for the lactating woman is estimated as the folate intake necessary to replace the folate secreted daily in human milk plus the amount required by the nonlactating woman to maintain folate