title: Folate-status response to a controlled folate intake in nonpregnant, pregnant, and lactating women.
abstract: BACKGROUND
  Folate dose-response studies in women of childbearing age who consumed a folic acid (FA)-containing multivitamin in the era of FA fortification are lacking.
  
  
  OBJECTIVE
  We sought to investigate folate-status response to a known folate dose comprising an FA-containing prenatal supplement (750 μg/d) plus natural food folate (400 μg/d) in third-trimester pregnant women, lactating women 5-15 wk postpartum, and nonpregnant women.
  
  
  METHODS
  Pregnant (n = 26), lactating (n = 28), and nonpregnant (n = 21) women consumed the study folate dose under controlled intake conditions for 10-12 wk. Blood, urine, and breast milk were collected at baseline, study midpoint, and study end.
  
  
  RESULTS
  Study-end serum total folate concentrations averaged ~30 ng/mL and did not differ by physiologic group (P = 0.876). Study-end urinary folate excretion represented ~9-43% of total folate intake and ranged from 100 to 500 μg/d. Third-trimester pregnant women excreted less urinary folate than did lactating (P = 0.075) and nonpregnant (P < 0.001) women. Lactating women excreted less (P < 0.001) urinary FA than did nonpregnant women. Breast-milk total folate concentrations remained constant (P = 0.244; 61.8 ng/mL at study end), whereas breast-milk FA concentrations increased (P = 0.003) to 24.1 ng/mL at study end.
  
  
  CONCLUSIONS
  The consumption of the study folate dose yielded a supranutritional folate status regardless of the physiologic state. Based on urinary folate excretion, folate use was greatest to least: pregnant > lactating > nonpregnant women. Breast-milk folate species were responsive to maternal folate intake, and FA made up ~40% of breast-milk total folate at study end. These findings warrant revisiting prenatal supplement FA formulation in populations exposed to FA-fortification programs.
authors.affiliation: Division of Nutritional Science, Cornell University, Ithaca, NY, USA.
authors.forename: Allyson A
authors.initials: AA
authors.lastname: West
authors.forename: Jian
authors.initials: J
authors.lastname: Yan
authors.forename: Cydne A
authors.initials: CA
authors.lastname: Perry
authors.forename: Xinyin
authors.initials: X
authors.lastname: Jiang
authors.forename: Olga V
authors.initials: OV
authors.lastname: Malysheva
authors.forename: Marie A
authors.initials: MA
authors.lastname: Caudill
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000378:metabolism / Q000652:urine; D004032:Diet; D019587:Dietary Supplements / Q000009:adverse effects; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism / Q000652:urine; D005527:Food, Fortified; D056726:Genetic Association Studies; D006801:Humans; D007774:Lactation / Q000097:blood / Q000378:metabolism* / Q000652:urine; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics / Q000378:metabolism; D008895:Milk, Human / Q000378:metabolism; D009518:New York; D009752:Nutritional Status; D010349:Patient Compliance; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy; D011263:Pregnancy Trimester, Third; D039401:Prenatal Nutritional Physiological Phenomena; D013763:Tetrahydrofolates / Q000097:blood / Q000378:metabolism / Q000652:urine
chemical_list: D015415:Biomarkers; D013763:Tetrahydrofolates; D005492:Folic Acid; C573423:MTHFR protein, human; D042965:Methylenetetrahydrofolate Reductase (NADPH2); C005984:5-methyltetrahydrofolate