Abstract
The transition from hunter-gatherer to sedentary agricultural lifestyles marked a change in human behaviour, with significant biological consequences to human life. It is assumed that the availability of staple crops allowed earlier weaning and increased fertility, leading to higher population density and sedentism, but increased disease and poor health outcomes. Although human health at the Neolithic transition has been studied around the world, few studies have specifically examined how breastfeeding and weaning practices may have changed during this distinct period of human history, and how this may have affected stress and fertility. The aim of this thesis is to assess if there was a relationship between maternal health, early childhood feeding practices (breastfeeding and weaning) and the development of physiological stress markers during the adoption of agricultural practices in a transitional Neolithic population at Man Bac (n=78) in Northern Vietnam (1800-1500 BC). To assess the relationship between weaning, diet, and stress at Man Bac, an examination of both isotopic and microscopic linear enamel hypoplasia (LEH) evidence for dietary change and stress using both permanent and deciduous teeth was undertaken.
In order to assess individual profiles of early childhood diet, breastfeeding and weaning, a δ15N and δ13C isotopic baseline for Man Bac was first established through bulk collagen analysis of faunal bone samples (3/30 samples had acceptable collagen preservation) and human bone samples (16/56 samples had acceptable collagen preservation). Incremental dentine isotopic analysis was then performed on 9 permanent teeth (6 had at least 1 increment with acceptable collagen preservation) and 5 deciduous teeth (2 had at least 1 increment with acceptable collagen preservation). Profiles of early childhood stress were assessed using the micropolynomial topographic methodology for identifying LEH on permanent teeth (34 individuals, 125 teeth total) and deciduous teeth (20 individuals, 70 teeth total). A rudimentary chronology of growth of the external deciduous crown was developed in order to estimate the age at which deciduous LEH developed. Eight individuals had preservation that allowed for an analysis of incremental isotopic profiles and were compared with the LEH profiles to identify if there was any relationship between LEH development and isotopic values. These results were interpreted within the context of previous bioarchaeological analysis of health, and the archaeological and environmental contexts of Man Bac.
Using incremental isotopic analysis, there is evidence for the reduction of breastmilk in the diet around approximately 1.5 years, and the cessation of detection of breastmilk in the diet at approximately 2.2 years. All individuals with permanent and deciduous teeth sampled had evidence for systemic LEH events. During deciduous and permanent tooth formation, the highest frequencies of LEH formation occurred during the prenatal period, the first 2 months after birth, at 7 months, and at 1.5 – 1.99 and 2.5-2.99 years of age, which supports the presence of maternal stress, as well as the potential introduction of infectious elements or nutrient deficient foodstuffs with supplementation of food at ~6 months. The period of ~1.5-2 years of age sees the development of LEH in most individuals with permanent teeth (86%) and correlates with the reduction of breastmilk in the diet, suggesting a period of physiological stress. Palaeopathological evidence for high levels of nutrient deficiencies of infants and children at the site indicate that LEH was likely related to these deficiencies during transitionary periods of early childhood diet, and from the influence of maternal stress associated with increased demand on mothers associated with high fertility in this Neolithic population.