Abstract
BackgroundThe maternal buffering hypothesis posits that human lactation biology can buffer milk against the mild-to-moderate malnutrition that occurred routinely in evolutionary history through the mobilization of maternal body reserves. This perspective may provide insights for understanding human milk immune content variation, such as milk sIgA, which protects infants’ intestines from microbial colonization and prevents diarrheal disease.ObjectiveTo investigate how maternal delivery of sIgA to milk may vary in a way that can buffer milk against maternal malnutrition, while taking into consideration infants’ varying needs for immune protection across age or by sex.MethodologyA cross-sectional study analyzed archived milk specimens from breastfeeding mothers in Ariaal communities of northern Kenya surveyed during the 2006 Horn-of-Africa drought. Multiple regression models for ln-transformed sIgA were constructed using maternal nutrition, infant age/sex and their interactions as predictors. Maternal nutrition variables included iron-deficiency anemia (IDA), vitamin A deficiency (VAD) and mid-upper arm circumference (MUAC). Infant vulnerability was considered high in young age and/or male sex.Results and implicationsMilk sIgA did not significantly differ by maternal IDA. Milk sIgA increased with infant age and maternal MUAC (n = 202). Significant interactions were observed between infant age and maternal VAD and between infant sex and maternal MUAC, such that milk sIgA content was low for younger infants particularly among VAD mothers, while among mothers with low MUAC, sIgA was lower for male infants. Results imply that mothers’ ability to deliver/buffer milk sIgA may be lowered when nutritional stress is combined with high infant vulnerability to infection.Lay SummaryHuman milk sIgA antibody content was low for younger infants among vitamin A deficient mothers. Among mothers with small arm-circumference, milk sIgA was lower for sons. Double burden of raising young or male infants with high needs for immune protection and being malnourished, might lower maternal sIgA delivery to milk.
Highlights
Human mothers’ milk provides nutrients, immune factors, and other bioactive compounds that nourish and protect their infants [1]
Significant interactions were observed between infant age and maternal vitamin A deficiency (VAD) and between infant sex and maternal mid-upper arm circumference (MUAC), such that milk sIgA content was low for younger infants among VAD mothers, while among mothers with low MUAC, sIgA was lower for male infants
This study investigated how milk sIgA levels may vary in relation to specific aspects of maternal nutrition—namely iron-deficiency anemia (IDA), VAD, and protein-energy nutrition—and infant age and sex using the frameworks of buffering infants against maternal malnutrition and protecting infants in proportion to their vulnerability to infectious disease
Summary
Human mothers’ milk provides nutrients, immune factors, and other bioactive compounds that nourish and protect their infants [1]. Infants are vulnerable to infections due to immature immune systems; in particular, their secretory immune system is nearly non-existent during a variable period after birth [9] For this reason, we focus on milk secretory immunity, sIgA antibodies, which constitute the largest antibody system of the human body [9]. The maternal buffering hypothesis posits that human lactation biology can buffer milk against the mild-to-moderate malnutrition that occurred routinely in evolutionary history through the mobilization of maternal body reserves. This perspective may provide insights for understanding human milk immune content variation, such as milk sIgA, which protects infants’ intestines from microbial colonization and prevents diarrheal disease. Infant vulnerability was considered high in young age and/or male sex
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call