Variation Among Populations in the Immune Protein Composition of Mother's Milk Reflects Subsistence Pattern

Authors

Laura D. Klein, Harvard University
Jincui Huang, University of California, Davis
Elizabeth A. Quinn, Washington University in St. Louis
Melanie A. Martin, University of California, Santa Barbara
Alicia A. Breakey, Harvard University
Michael Gurven, University of California, Santa Barbara
Hillard Kaplan, Chapman UniversityFollow
Claudia Valeggia, Yale University
Grazyna Jasienska, Jagiellonian University, Poland
Brooke Scelza, University of California, Los Angeles
Carlito B. Lebrilla, University of California, Davis
Katie Hinde, Harvard University

Document Type

Article

Publication Date

10-13-2018

Abstract

Lay Summary: Adaptive immune proteins in mothers’ milk are more variable than innate immune proteins across populations and subsistence strategies. These results suggest that the immune defenses in milk are shaped by a mother’s environment throughout her life.

Background and objectives: Mother’s milk contains immune proteins that play critical roles in protecting the infant from infection and priming the infant’s developing immune system during early life. The composition of these molecules in milk, particularly the acquired immune proteins, is thought to reflect a mother’s immunological exposures throughout her life. In this study, we examine the composition of innate and acquired immune proteins in milk across seven populations with diverse disease and cultural ecologies.

Methodology: Milk samples (n = 164) were collected in Argentina, Bolivia, Nepal, Namibia, Philippines, Poland and the USA. Populations were classified as having one of four subsistence patterns: urban-industrialism, rural-shop, horticulturalist-forager or agro-pastoralism. Milk innate (lactalbumin, lactoferrin and lysozyme) and acquired (Secretory IgA, IgG and IgM) protein concentrations were determined using triple-quadrupole mass spectrometry.

Results: Both innate and acquired immune protein composition in milk varied among populations, though the acquired immune protein composition of milk differed more among populations. Populations living in closer geographic proximity or having similar subsistence strategies (e.g. agropastoralists from Nepal and Namibia) had more similar milk immune protein compositions. Agropastoralists had different milk innate immune protein composition from horticulturalist-foragers and urban-industrialists. Acquired immune protein composition differed among all subsistence strategies except horticulturist-foragers and rural-shop.

Conclusions and implications: Our results reveal fundamental variation in milk composition that has not been previously explored in human milk research. Further study is needed to understand what specific aspects of the local environment influence milk composition and the effects this variation may have on infant health outcomes.

Comments

This article was originally published in Evolution, Medicine, and Public Health, volume 2018, issue 1, in 2018. https://doi.org/10.1093/emph/eoy031

Recommended Citation

Klein, L. D., Huang, J., Quinn, E. A., et al. (2018). Variation among populations in the immune protein composition of mother's milk reflects subsistence pattern. Evolution, Medicine, and Public Health, 2018(1), 230-245. https://doi.org/10.1093/emph/eoy031

Peer Reviewed

1

Copyright

Oxford University Press

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 License.