New standard for dietary folate intake in pregnant women

The Institute of Medicine Panel for Folate and Other B Vitamins and Choline considered data from population-based and metabolic studies to revise the dietary intake standards for pregnancy. The recommended dietary allowance ( RDA) for pregnant women is the average daily dietary intake sufficient to m eet the requirements of 97-98% of pregnant women. The RDA is derived from t he amount estimated to meet the requirement of half of healthy pregnant wom en, or the estimated average requirement (EAR). Maintenance of red cell fol ate was selected as the primary indicator of adequacy of folate status duri ng pregnancy. The dietary folate equivalent (DFE) was used to interpret stu dies in which folate was provided as a combination of food folate and synth etic folic acid because folic acid is more bioavailable than is food folate . Many population-based studies confirmed that approximate to 680 nmol (app roximate to 300 mu g) folic acid/d consumed in conjunction with a low-folat e diet prevented folate deficiency in pregnant women. Additional studies sh owed that 227 nmol (100 mu g) folic acid/d was inadequate to maintain norma l folate status in a significant percentage of the groups assessed. The EAR was derived by adding the DFE of this quantity [454 nmol (200 mu g)/d] to the EAR for nonpregnant women [725 nmol (320 mu g)/d] to provide an EAR of 1178 nmol (520 mu g)/d. The RDA of 1362 nmol (600 mu g) DFE/d was derived b y multiplying the EAR by 1.2 to account for an estimated 10% CV. Data from the metabolic studies support an RDA of 1362 nmol (600 mu g) DFE/d on the b asis of the maintenance of normal red cell folate concentrations and agree with the findings from the population studies that 1362 nmol DFE/d is adequ ate to maintain normal folate status in pregnant women.