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Vitamin A dynamics in breastmilk and liver stores: A life history perspective
Author(s) -
Fujita Masako,
ShellDuncan Bettina,
Ndemwa Philip,
Brindle Eleanor,
Lo YunJia,
Kombe Yeri,
O'connor Kathleen
Publication year - 2011
Publication title -
american journal of human biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.559
H-Index - 81
eISSN - 1520-6300
pISSN - 1042-0533
DOI - 10.1002/ajhb.21195
Subject(s) - parity (physics) , vitamin , weaning , lactation , vitamin d and neurology , medicine , postpartum period , physiology , breastfeeding , pregnancy , endocrinology , biology , pediatrics , physics , particle physics , genetics
Objectives: Newborns are dependent on breastmilk vitamin A for building hepatic stores of vitamin A that will become critical for survival after weaning. It has been documented that vitamin A concentrations in breastmilk decline across the first year postpartum in both well‐nourished and malnourished populations. The reason for this decline has been assumed to be a sign of concurrently depleting maternal hepatic stores. This study investigates this assumption to clarify why the decline occurs, drawing on life history theory. Methods: A cross sectional survey was conducted among lactating mothers in Kenya in 2006. Data were used to examine (1) the relationship between liver vitamin A and time, (2) if the relationship between milk and liver vitamin A varies by time, and (3) by maternal parity. Results: The relationship between liver vitamin A and time fits the quadratic pattern with marginal significance ( P = 0.071, n = 192); the liver vitamin A declined during early postpartum then recovered in late postpartum time, controlling covariates. The milk‐liver vitamin A relationship varied by postpartum time periods ( P = 0.03) and by maternal parity ( P = 0.005). Mothers in earlier postpartum or higher parity had a stronger positive relationship between milk and liver vitamin A than mothers in later postpartum or lower parity. Conclusions: Our observations are consistent with life history tradeoffs and negate the assumption that maternal hepatic and milk vitamin A decline together. Rather, maternal liver vitamin A has a dynamic relationship with milk vitamin A, particularly depending on postpartum time and maternal parity. Am. J. Hum. Biol., 2011. © 2011 Wiley‐Liss, Inc.