Maternal folate status during extended lactation and the effect of supplemental folic acid

• Published in: The American journal of clinical nutrition 1999-02, Vol.69 (2), p.285-292
• Main Authors: MACKEY, A. D, PICCIANO, M. F
• Format: Article
• Language: English
• Subjects: Adult; Analysis of Variance; Anthropometry; Biological and medical sciences; Breastfeeding & lactation; Child Development; Dietary Supplements; Double-Blind Method; Female; Folic Acid - administration & dosage; Folic Acid - analysis; Folic Acid - blood; Fundamental and applied biological sciences. Psychology; Hematologic Tests; Homocysteine - blood; Humans; Infant, Newborn; Lactation - metabolism; Longitudinal Studies; Milk, Human - chemistry; Mother. Fetoplacental unit. Mammary gland. Milk; Pregnancy. Parturition. Lactation; Vertebrates: reproduction; Vitamin B
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/69.2.285

Folate requirements during lactation are not well established. We assessed the effects of dietary and supplemental folate intakes during extended lactation. Lactating women (n = 42) were enrolled in a double-blind, randomized, longitudinal supplementation trial and received either 0 or 1 mg folic acid/d. At 3 and 6 mo postpartum, maternal folate status was assessed by measuring erythrocyte, plasma, milk, and dietary folate concentrations; plasma homocysteine; and hematologic indexes. Infant anthropometric measures of growth, milk intake, and folate intake were also assessed. In supplemented women, values at 6 mo for erythrocyte and milk folate concentrations and for plasma homocysteine were not significantly different from those at 3 mo. In supplemented women compared with unsupplemented women at 6 mo, values for erythrocyte folate (840 compared with 667 nmol/L; P < 0.05), hemoglobin (140 compared with 134 g/L; P < 0.02), and hematocrit (0.41 compared with 0.39; P < 0.02) were higher and values for reticulocytes were lower. In unsupplemented women, milk folate declined from 224 to 187 nmol/L (99 to 82 ng/mL), whereas plasma homocysteine increased from 6.7 to 7.4 micromol/L. Dietary folate intake was not significantly different between groups (380+/-19 microg/d) and at 6 mo was correlated with plasma homocysteine in unsupplemented women (r = -0.53, P < 0.01) and with plasma folate in supplemented women (r = 0.49, P < 0.02). A dietary folate intake of approximately 380 microg/d may not be sufficient to prevent mobilization of maternal folate stores during lactation.