Thesis Format
Integrated Article
Degree
Doctor of Philosophy
Program
Anthropology
Supervisor
Waters-Rist, Andrea L.
2nd Supervisor
Longstaffe, Fred J.
3rd Supervisor
Nelson, Andrew J.
Abstract
This dissertation investigates early childhood diet through compound-specific isotope analysis (CSIA) of amino acids (AAs). Traditional bioarchaeological methods often yield ambiguous results, but CSIA-AA offers a refined approach, distinguishing dietary from non-dietary isotopic changes.
Fingernail samples (n = 43) from three contemporary mother-infant dyads were analyzed to assess CSIA-AA’s potential in reconstructing early childhood diet and health. Findings from participants were then applied to study pre-Hispanic breastfeeding and weaning practices in four individuals from Peru’s Jequetepeque Valley.
Stable carbon isotope analysis of modern fingernails revealed that glycine and glutamate could track the onset of weaning, while nitrogen isotopes of proline could trace breastmilk consumption. Results also indicated that stable carbon isotopes of glycine and glutamate, along with nitrogen isotopes of phenylalanine, show physiological and pathological stress.
Using these biomarkers, results from incremental dentine samples (n = 31) of the four archaeological individuals revealed that weaning ages varied from 2.2 to 3.8 years. To contextualize these findings within broader pre-Hispanic diets, bulk collagen isotopic data from dentine and bone samples (n = 8) from the Jequetepeque Valley were combined with published stable isotope data from seven archaeological sites (AD 100-1532) for Bayesian statistical analysis. This showed that locality and cultural affiliation significantly influenced dietary patterns, affecting children’s nutrition across periods and sites.
This study provides valuable insights into pre-Hispanic childhood feeding practices, demonstrating the utility of CSIA-AA in tracking early childhood nutrition and physiological stress. These findings have significant implications for archaeology, nutrition, and ecology, as they establish CSIA-AA as a powerful tool for reconstructing early childhood feeding practices, understanding AA metabolism, and exploring the cultural and health dynamics of past and present populations.
Summary for Lay Audience
This dissertation explores breastfeeding and weaning using compound-specific stable isotope analysis (CSIA) of individual amino acids (AAs), a novel approach in bioarchaeological studies of childhood diet and health. CSIA improves upon traditional stable isotope methods that analyze bulk proteins by allowing researchers to examine individual AAs. Amino acids are the basic building blocks of proteins, each with a unique metabolic pathway that can indicate dietary or non-dietary factors.
The regional focus of this study was the Jequetepeque Valley of Peru as very little research has been conducted on pre-Hispanic breastfeeding and weaning practices. Since this region underwent significant sociopolitical changes over ~1000 years (AD 100-1532), investigating dietary transitions in four pre-Hispanic individuals sheds light on infant diet, health, and their relationships with socioeconomic and political environments.
First, fingernail samples from three contemporary mother-infant dyads of known diet and health were analyzed to establish a protocol for CSIA-AA. Results from modern samples guided the analysis of four incrementally sampled archaeological teeth.
Since carbon and nitrogen are incorporated differently into AAs, stable carbon and nitrogen isotopes were analyzed separately. Findings revealed that δ13C of glycine and glutamate tracked the onset of weaning, while δ15N of proline traced breastmilk consumption. Physiological and/or pathological stress was also identified using δ13C and δ15N of AAs.
Using these AA biomarkers, it was determined that the four archaeological individuals were weaned between 2.2 and 3.8 years of age. Stable isotope results were also analyzed through a Bayesian mixing model, to examine dietary changes on Peru’s North Coast. This analysis situated breastfeeding and weaning patterns within the broader context of dietary shifts influenced by sociopolitical conditions. This analysis revealed that diets were primarily shaped by location and cultural practices, with greater disparities in access to elite foods during the Late Intermediate Period (AD 1000-1532).
This study significantly advances stable isotope analysis by establishing CSIA-AA as a tool for tracking early childhood nutrition and stress. It contributes to the fields of archaeology, nutrition, and ecology, offering insights into past dietary practices and AA metabolic adaptations. This interdisciplinary research is valuable for both pre-historic inquiry and modern health sciences.
Recommended Citation
Salahuddin, Hana, "Exploring Early Life Nutrition: Amino Acid Stable Isotopes as Biochemical Markers" (2024). Electronic Thesis and Dissertation Repository. 10597.
https://ir.lib.uwo.ca/etd/10597
