Vitamin A dynamics in breastmilk and liver stores: A life history perspective

Abstract

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.

Micronutrients and neurodevelopment: An update

“…All mothers have reduced retinol levels in the first year postpartum, which progressively decreases vitamin A transfer from breast milk to the baby. 35 This reinforces the concept that it is necessary to provide vitamin A supplementation during lactation. 36 …”

Field and laboratory methods in human milk research

“…While prior clinical and nutritional researchers have thoroughly described the composition of milk, human biologists have the opportunity to develop hypotheses filtered through the lens of human variation (Fujita et al, 2011;Miller, 2011;Quinn, 2011), evolution Hinde and Milligan, 2011), and culture (Miller, 2011) to further understand this integral experience of mothers and infants. As human biologists, we are well placed to incorporate a global perspective into the study of human milk.…”

“…Historical documents suggest that infant mortality rates were very high in the absence of maternal milk, illustrating the selective pressure on milk (Hinde and Milligan, 2011). Milk, then, likely communicates critical ecological information to the infant, such as maternal condition or nutritional availability in the environment (Fujita et al, 2011;Hinde and Capitanio, 2010;Hinde, 2013), pathogen burdens (Miller and McConnell, 2011;Prentice et al, 1983), and potentially long-term environmental information (Quinn, 2011).…”

“…Researchers have only begun to define normal milk variation across populations and how it influences the postnatal period and beyond (Neville et al, 2012). Many of the emerging questions in human biology are linked to lactation, from unique aspects of primate Milligan and Bazinet, 2008) and human life histories (Fujita et al, 2011), parental investment (Fujita et al, 2012;Hinde, 2009;Powe et al, 2010), and developmental programming (de Moura et al, 2008;Hinde and Capitano, 2010;Miralles et al, 2006;Newburg et al, 2010;Palou et al, 2009;Pico et al, 2007;Prentice, 2005;Quinn, 2011;Quinn et al, 2012;Savino et al, 2009;Stocker and Cawthorne, 2008;Weyerman et al, 2007). In addition, lactation is implicated in human evolutionary biology, including the evolution of large brains and body fat (Kuzawa, 1998;Martin, 1981), childhood (Bogin, 1999;Konner, 2010;Sellen, 2007), reproductive timing (Al-Sahab et al, 2011) and the developmental origins of adult metabolism (Kuzawa and Quinn, 2009;Wells, 2003).…”

Micronutrientes y neurodesarrollo: actualización

“…Las concentraciones de retinol disminuyen en todas las madres el primer año posparto, lo que reduce progresivamente la transferencia de vitamina A de la leche materna al bebé. 35 Esto refuerza el concepto de la necesidad de suplementación de vitamina A durante la lactancia. 36 …”