Thesis
HUMAN MILK IMMUNE FACTORS AND TRIVERS WILLARD HYPOTHESIS: THE INSPIRE STUDY
Washington State University
Master of Arts (MA), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000003124
Handle:
https://hdl.handle.net/2376/125335
Abstract
The Trivers-Willard hypothesis posits that maternal investment in offspring is influenced by maternal condition and infant sex, as female offspring are likely to be successful regardless of condition while males are likely to be successful only when high quality. While primarily investigated in humans in the context of behavioral investment bias, here, we test the Trivers Willard hypothesis through an investigation of maternal investment via human milk immune factor concentrations. Breastfeeding represents one of the most costly and intense forms of human parental investment, and human milk immune factors are essential in protecting infants against pathogens encountered in their environments. We hypothesize that human milk immune factors may vary in response to proximate cues outlined in the Trivers Willard hypothesis. We examine the relationship between concentrations of immune factors in maternal milk (IgA, IgM, IgG, EGF, TGFβ2 and IL-10) and infant sex as it interacts with maternal condition, as proxied by maternal BMI and diet diversity scores (DDS). We use milk samples collected from 358 breastfeeding mothers from 10 sites across 8 countries (Ethiopia, The Gambia, Ghana, Kenya, Spain, Sweden, Peru, and the United States). Results indicate no overall significant effects of infant sex or maternal condition on concentrations of immune factors in our study. However, EGF trended towards higher in the milk of mothers with high DDS. In addition, IgG concentrations were higher in the milk of mothers in good condition (high diet diversity) with male infants than mothers in good condition with female infants. Overall, however, our results only provide minimal support for our hypothesis that variation of human milk immune factor concentrations are reflective of maternal condition and infant sex. Our findings contribute to the understanding of differential maternal biological investment and whether human milk immune variation is influenced by maternal and infant characteristics.
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Details
- Title
- HUMAN MILK IMMUNE FACTORS AND TRIVERS WILLARD HYPOTHESIS: THE INSPIRE STUDY
- Creators
- Beatrice Queiroz Caffe
- Contributors
- Courtney L Meehan (Advisor)Aaron D Blackwell (Committee Member)Mark A. McGuire (Committee Member)Michelle K McGuire (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Anthropology, Department of
- Theses and Dissertations
- Master of Arts (MA), Washington State University
- Publisher
- Washington State University
- Number of pages
- 50
- Identifiers
- 99900651899301842
- Language
- English
- Resource Type
- Thesis