Milk folate secretion and folate status of suckling pups during iron deficiency
1989
O'Connor, D.L. | Picciano, M.F. | Sherman, A.R.
The present study was designed to determine when in lactation maternal iron deficiency results in a depression of milk folate secretion and the extent to which the quantity of folate delivered to the nursing rat pup is diminished. Dams (n=42) were fed diets containing 2 mg/kg folate and either 8 (Fe-) or 250 (Fe+) mg/kg iron throughout gestation and lactation. On either d 7, 12 or 17, dams were milked and animals were sacrificed. Both free and total milk folate activities increased from d 7 to d 17 among Fe+ animals (p less than 0.0001). In contrast, total milk folate decreased (52%) among Fe- dams after d 12 of lactation. Total milk folate contents were 29%, 42% (p less than 0.05), and 81% (p less than 0.0001) lower in samples from iron-deficient compared to control dams on d 7, 12 and 17, respectively. In addition, iron-deficient dams secreted milk with a substantially reduced percentage of long chain folylpolyglutamates. Iron-deficient pups ingested 40% (p less than 0.05) and 72% (p less than 0.0004) less total folate (pmol/g) on d 12 and 17 of lactation, respectively. Plasma and kidney folate concentrations were significantly reduced in Fe dams (p less than 0.001). Plasma folate concentrations (d 17) were significantly lowered but liver and RBC folate concentrations were significantly elevated in Fe- pups. Results show that reduced milk folate secretion is an early manifestation of maternal iron deficiency which worsens as lactation advances and that total folate ingestion by nursing pups is likewise progressively reduced.
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