Exploring ideas about isotopic variation in breastfeeding and weaning within and between populations: Case studies from the American midcontinent

Abstract

Infant feeding practices are partially constrained by the biological demands of infants and mothers but vary within those constraints based on factors such as subsistence practices, health, class and ethnic variations, and the presence or absence of foods that can be substituted for breastmilk. Over the past 20 years, nitrogen stable isotope ratios have been used to explore infant feeding practices in past populations. Recent studies have moved from normative approaches primarily focused on weaning time to examinations of intrapopulation variation. Juvenile and adult stable nitrogen isotope ratios from five sites in the midcontinental USA spanning almost 5,000 years provide an opportunity to examine the relationships between subsistence practices and social organization to juvenile diets reflected in nitrogen and carbon stable isotope ratios and how interpretations of juvenile isotopic variability have changed over time. Infant feeding practices were variable in all populations and between roughly contemporary groups with similar ways of life. As reported before, no change in weaning time was seen with the appearance of food production from Late Archaic hunter‐gatherers (Indian Knoll and Carlston Annis sites) to maize agriculturalists (Angel and Tinsley Hill sites), but carbon stable‐isotope ratios show differences in childhood diet and the consumption of supplemental foods by prehistoric maize agriculturalists. Variability at four prehistoric sites was much less than that seen in an early 19th century cemetery (Old Frankfort Cemetery). Although many juveniles at Old Frankfort followed a trajectory of breastfeeding and weaning similar to that seen at the prehistoric sites, there was an unusually large amount of variation in juvenile and adult diets at Old Frankfort Cemetery. Additional studies on early industrial multi‐ethnic frontier populations are needed to better understand the significance of the variation in this type of population.

Sex‐biased parental investment and female wealth accumulation in ancientCalifornia

“…In many cases, discrete archaeological cemetery populations limit the potential for cross-status analysis, with burial populations explicitly recognized as elite (e.g., Gregoire, 2019) or poor (e.g., Väre et al, 2022). In other studies, differences in status may be present, but are strongly correlated with other variables under analysis, including mobility, changing subsistence practices, demography, or cultural chronology (e.g., Pfeiffer et al, 2017;Scharlotta et al, 2018;Schurr, 2018). Because of uncertainty regarding the inheritance of status, markers of individual burial status do not necessarily imply that parents enjoyed the same status.…”

Stable isotope analysis of human bone from Ganj Dareh, Iran, ca. 10,100 calBP

“…There has been growing evidence that other than diet, high levels of stress exposure and malnutrition may also cause variability in the isotopic compositions of humans [29,[78][79][80], mainly in δ 15 N values [79]. However, at Ganj Dareh, the corresponding patterns in both δ 13 C and δ 15 N values of the subadults suggested that diet was a stronger factor than metabolic disruption for the trend in these individuals' isotopic compositions.…”

Tracking breastfeeding and weaning practices in ancient populations by combining carbon, nitrogen and oxygen stable isotopes from multiple non-adult tissues

“…Refining models to reconstruct breastfeeding and weaning practices (BWPs) of past populations is of great interest to bioanthropologists, as it provides information about demographic patterns, health [ 1 – 5 ], non-adult rearing practices [ 6 , 7 ], and subsistence strategies [ 8 – 10 ]. In relation to paleodemography, higher fertility rates and reduced births intervals have been associated with shorter breastfeeding stages [ 11 – 13 ].…”