title: Postpartum folic acid supplementation of adolescents: impact on maternal folate and zinc status and milk composition.
abstract: The objectives of the present study were to assess the impact of lactation on the folate status of adolescents and determine the effect of ingestion of a low-dose postpartum (PP) folic acid supplement on maternal folate and zinc status and milk composition. Pregnant adolescents (aged 14-19 y; n = 71) were recruited; those who initiated breast-feeding on delivery were randomly assigned to a folic acid supplement lactating (SL; 300 micrograms/d, n = 14) group or to a placebo lactating (PL; n = 15) group. Subjects who initiated formula feeding were given a placebo (FF; n = 18). Dietary intakes (two 24-h recalls) were recorded and blood and milk samples were collected at 4, 8, and 12 wk PP. Of the adolescents, 71%, 48%, 67%, and 60% had folate, iron, vitamin B-12, and zinc intakes, respectively, below their predicted requirements. Despite this, most blood indexes were within normal ranges, probably reflecting the subjects' use of supplements during pregnancy. Red blood cell (r = -0.49, P < 0.05) and plasma (r = -0.42, P = 0.08) folate concentrations were negatively correlated with milk zinc concentrations. Mean red blood cell folate content declined between 4 and 12 wk PP among PL (31%) and FF (34%) subjects (P < 0.05) but not among SL subjects. Hence, 300 micrograms folic acid/d was sufficient to prevent a decline in blood folate values of these adolescents PP.
authors.affiliation: Division of Applied Human Nutrition, University of Guelph, Ontario, Canada.
authors.forename: S E
authors.initials: SE
authors.lastname: Keizer
authors.forename: R S
authors.initials: RS
authors.lastname: Gibson
authors.forename: D L
authors.initials: DL
authors.lastname: O'Connor
mesh_terms: D000293:Adolescent; D000328:Adult; D004032:Diet / Q000592:standards; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000737:chemistry; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage / Q000032:analysis* / Q000494:pharmacology*; D005527:Food, Fortified; D006801:Humans; D007774:Lactation / Q000097:blood / Q000378:metabolism / Q000502:physiology; D008895:Milk, Human / Q000737:chemistry*; D049590:Postpartum Period / Q000378:metabolism* / Q000502:physiology; D011247:Pregnancy; D012044:Regression Analysis; D015032:Zinc / Q000032:analysis* / Q000097:blood
chemical_list: D005492:Folic Acid; D015032:Zinc