Stable isotope ratio analysis of breastfeeding and weaning practices of children from medieval Fishergate House York, UK

Abstract

Rib collagen of 51 juveniles and 11 adult females from the late medieval Fishergate House cemetery site (York, UK) were analyzed using nitrogen and carbon stable isotope ratio analysis to determine the weaning age for this population and to reconstruct diet. The juveniles' ages ranged from fetal to 5-6 years, while the females were of reproductive age. Previous researchers suggested that the children from Fishergate House might have been weaned later than the medieval British norm of 2 years, based on a mortality peak at 4-6 years of age. The results show weaning was complete by 2 years of age, agreeing with previous British weaning studies. The adult female δ(15) N values have a mean of 11.4‰ ± 1.1‰ and the δ(13) C values have a mean of -19.4‰ ± 0.4‰. These findings are consistent with previous isotopic studies of female diet in York during this period, though slightly lower. The weaned juvenile nitrogen values were found to be higher than the adult females (12.4‰ ± 1.0‰ for δ(15) N and -19.7‰ ± 0.5‰ for δ(13) C), which might indicate a dependence on higher trophic level proteins such as marine fish or pork. Marine fish is considered a high status food and children are considered low-status individuals at this time, making this a particularly interesting finding. Weaning does not appear to coincide with peak mortality, suggesting environment factors may be playing a larger role in child mortality at Fishergate House.

Reconstruction of breastfeeding and weaning practices using stable isotope and trace element analyses: A review

“…Haydock et al (2013) targeted British BWPs in the late Anglo-Saxon (978-1040 cal AD) and compared the result with several previous isotopic studies on British BWPs; they found that the weaning ages become younger from the Iron Age to the 19th century. Their results of decreasing weaning ages are consistent with the newly reconstructed weaning ages of a population in medieval (10th to 16th centuries AD) Britain (Burt, 2013). Howcroft et al (2014) reconstructed infant feeding practices in a hunter-gatherer skeletal population from the Middle Neolithic Pitted Ware Culture (after 2750 BC), Sweden, and showed that the majority of subadults were breastfed until the third or fourth year of age.…”

Individual dietary patterns during childhood: an archaeological application of a stable isotope microsampling method for tooth dentin

“…The initial osteology report from Fishergate House indicated a high mortality rate at 4e6 years, which does not match the weaning period (2 years) found in contemporaneous British communities (Burt, 2013;Fuller et al, 2003Fuller et al, , 2006bHolst, 2005;Jay et al, 2008;Mays et al, 2002;Richards et al, 2002). The weaned child diet at Fishergate House reconstructed using a small sample of ribs is unusual as it is not the same as that of the adult females studied (Burt, 2013).…”

“…The weaned child diet at Fishergate House reconstructed using a small sample of ribs is unusual as it is not the same as that of the adult females studied (Burt, 2013). At Fishergate House, weaned children appear to have a diet rich in marine protein and pig much like high socioeconomic individuals in a neighboring York suburb rather than a grain based diet as seen with their poor contemporaries (Burt, 2013;Fuller et al, 2003;Mays et al, 2002;Richards, 2007a, 2007b;Richards et al, 2002).…”

“…The initial osteology report from Fishergate House indicated a high mortality rate at 4e6 years, which does not match the weaning period (2 years) found in contemporaneous British communities (Burt, 2013;Fuller et al, 2003Fuller et al, , 2006bHolst, 2005;Jay et al, 2008;Mays et al, 2002;Richards et al, 2002). The weaned child diet at Fishergate House reconstructed using a small sample of ribs is unusual as it is not the same as that of the adult females studied (Burt, 2013). At Fishergate House, weaned children appear to have a diet rich in marine protein and pig much like high socioeconomic individuals in a neighboring York suburb rather than a grain based diet as seen with their poor contemporaries (Burt, 2013;Fuller et al, 2003;Mays et al, 2002;Richards, 2007a, 2007b;Richards et al, 2002).…”

Social stratigraphy in Late Iron Age Switzerland: stable carbon, nitrogen and sulphur isotope analysis of human remains from Münsingen

“…This result derives from a higher trophic level due to breastfeeding. Nursing babies consume mother's milk which is enriched with 15 N (Bourbou et al 2013;Burt 2013;Fuller et al 2006;Katzenberg 2008;Katzenberg et al 1996). In this study, only one child (A50) aged 3 to 5 years could be analysed for stable isotope ratios.…”