M (2015) Infant mortality and isotopic complexity: new approaches to stress, maternal health and weaning. American Journal of Physical Anthropology. 157(3): 441-457, which will be published in final form at http://dx.doi.org/10.1002/ ajpa.22736. Materials and MethodsChildhood dentine collagen  13C and  15N profiles were produced from horizontal sections of permanent and deciduous teeth following the direction of development. These were from two 19 th -century sites (n = 24) and a small number (n = 5) of prehistoric samples from Great Britain and Ireland. ResultsThese high-resolution data exhibit marked differences between those who survived childhood and those who did not, the former varying little and the latter fluctuating widely. DiscussionBreastfeeding and weaning behavior have a significant impact on the morbidity and mortality of infants and the adults they become. In the absence of documentary evidence, archaeological studies of bone collagen of adults and juveniles have been used to infer the prevalence and duration of breastfeeding. These interpretations rely on certain assumptions about the relationship between isotope ratios in the bone collagen of the adult females and the infants who have died. The data from this study suggest a more complex situation than previously proposed and the potential for a new approach to the study of maternal and infant health in past populations. 3Carbon and nitrogen stable isotope ratios from archaeological bone and dental tissues have been used for more than 20 years to investigate breastfeeding and weaning practices. Early studies, which revolutionized the use of bone collagen stable isotopes, identified patterns within the tissues of fetuses (less than 28 weeks gestation), neonates (28-40 weeks gestation) and infants (28 days to 1 year post-birth)(Lewis and Gowland 2007) which revealed the potential to investigate the duration of breastfeeding and weaning in past populations (e.g. Fogel et al. 1989;Katzenberg et al. 1993;Schurr 1997;White and Schwarcz 1994). Katzenberg (1996) reviewed previous interpretations of the method and cautioned against the potential effect of using the tissues of dead infants without knowing the cause of death and the potential for stress, bone turnover and growth to alter the isotope ratios of both mother and infant. Subsequently, a simplified method, based on a mathematical model of the isotope ratio variations which should be associated with a dietary change from breastmilk to the prevailing diet of the adult population, was proposed and widely accepted (Schurr 1997;Millard, 2000;Jay, 2008). This method has since been applied to data from modern, historical and archaeological tissues to estimate the timing of weaning and whether breastfeeding occurred over prolonged periods.The mathematical model has been used pragmatically despite the often-acknowledged fact that it makes several assumptions about the relationships of mother and infant body tissues, their diets, and the comparability of individual members of a population with the o...

We present here the results of carbon and nitrogen isotopic analysis of bone collagen undertaken on all skeletal remains of infants and young children below the age of 6 years (n = 34) from the internationally important British cemetery site at Wetwang Slack in East Yorkshire (middle Iron Age, ca. 4th to 2nd centuries BC). The aim of the study is to investigate infant diet, with particular reference to breastfeeding and weaning practices, and to compare the data with previously published studies of archaeological populations, particularly in the context of the variation in data patterns to be seen between sites. The skeletal remains from Wetwang Slack form the only prehistoric collection in the UK, prior to the Romano-British period, with sufficient individuals in this age group to make such an isotopic study viable alongside associated adults and older children. The data are compared in detail with published data from two other sites, one from 19th century Canada and the other from Medieval Britain. The results suggest an unusual situation at Wetwang Slack, with neither the nitrogen nor the carbon isotope ratios conforming to expectations when compared with the putative mothers. We discuss how these data compare with the expectation for breastfed infants and we interpret the divergence in this case to be due to restricted breastfeeding and the early introduction of supplementary foods.

This study investigates the application of sulphur isotope ratios (d 34 S) in combination with carbon (d 13 C) and nitrogen (d 15 N) ratios to understand the influence of environmental sulphur on the isotopic composition of archaeological human and faunal remains from Roman era sites in Oxfordshire, UK. Humans (n = 83), terrestrial animals (n = 11), and freshwater fish (n = 5) were analysed for their isotope values from four locations in the Thames River Valley, and a broad range of d 34 S values were found. The d 34 S values from the terrestrial animals were highly variable (À13.6& to +0.5&), but the d 34 S values of the fish were clustered and 34 S-depleted (À20.9& to À17.3&). The results of the faunal remains suggest that riverine sulphur influenced the terrestrial sulphur isotopic signatures. Terrestrial animals were possibly raised on the floodplains of the River Thames, where highly 34 S-depleted sulphur influenced the soil. The humans show the largest range of d 34 S values (À18.8& to +9.6&) from any archaeological context to date. No differences in d 34 S values were found between the males (À7.8 ± 6.0&) and females (À5.3 ± 6.8&), but the females had a linear correlation (R 2 = 0.71; p < 0.0001) between their d 15 N and d 34 S compositions. These d 34 S results suggest a greater dietary variability for the inhabitants of Roman Oxfordshire than previously thought, with some individuals eating solely terrestrial protein resources and others showing a diet almost exclusively based on freshwater protein such as fish. Such large dietary variability was not visible by analysing only the carbon and nitrogen isotope ratios, and this research represents the largest and most detailed application of d 34 S analysis to examine dietary practices (including breastfeeding and weaning patterns) during the Romano-British Period.

No abstract