A long-term study of stable isotope ratios of fingernail keratin and amino acids in a mother-infant dyad

OBJECTIVE

To evaluate the potential of compound-specific isotope analysis of amino acids (CSIA-AA) for investigating infant feeding practices, we conducted a long-term study that compared infant and maternal amino acid (AA) nitrogen isotope ratios.

MATERIALS AND METHODS

Fingernail samples were collected from a single mother-infant dyad over 19 months postpartum. Carbon and nitrogen stable isotope ratios were measured in the bulk keratin of the fingernail samples. Selected samples were then hydrolyzed and derivatized for compound-specific nitrogen isotope analysis of keratin AAs.

RESULTS

As in previous studies, infant bulk keratin nitrogen isotope values increased during exclusive breastfeeding and fell with the introduction of complementary foods and eventual cessation of breastfeeding. Infant trophic AAs had elevated nitrogen isotope values relative to the mother, while the source AAs were similar between the mother and infant. Proline and threonine appeared to track the presence of human milk in the infant's diet as the isotopic composition of these AAs remained offset from maternal isotope values until the cessation of breastfeeding.

DISCUSSION

Although CSIA-AA is costly and labor intensive, it appears to hold potential for estimating the duration of breastfeeding, even after the introduction of complementary foods. Through the analysis of a full suite of AAs, it may also yield insights into infant physiology and AA synthesis.

Diets, stress, and disease in the Etruscan society: Isotope analysis and infantile skeletal palaeopathology from Pontecagnano (Campania, southern Italy, 730-580 BCE)

Susceptibility to morbidity and mortality is increased in early life, yet proactive measures, such as breastfeeding and weaning practices, can be taken through specific investments from parents and wider society. The extent to which such biosocialcultural investment was achieved within 1st millennium BCE Etruscan society, of whom little written sources are available, is unkown. This research investigates life histories in non-adults and adults from Pontecagnano (southern Italy, 730-580 BCE) in order to track cross-sectional and longitudinal breastfeeding and weaning patterns and to characterize the diet more broadly. Stable carbon and nitrogen isotope analysis of incrementally-sampled deciduous and permanent dentine (n = 15), bulk bone collagen (n = 38), and tooth enamel bioapatite (n = 21) reveal the diet was largely based on C3 staple crops with marginal contributions of animal protein. Millet was found to play a role for maternal diet and trajectories of breastfeeding and feeding for some infants and children at the site. The combination of multiple isotope systems and tissues demonstrates exclusive breastfeeding was pursued until 0.6 years, followed by progressive introduction of proteanocius supplementary foods during weaning that lasted between approximately 0.7 and 2.6 years. The combination of biochemical data with macroscopic skeletal lesions of infantile metabolic diseases and physiological stress markers showed high δ15Ndentine in the months prior to death consistent with the isotopic pattern of opposing covariance.

Extracting the truth through chemical analyses: Early life histories of Victorian-era dental patients in Aotearoa New Zealand

OBJECTIVES

There are few bioarcheological analyses of life experiences in colonial period Aotearoa New Zealand, despite this being a time of major adaptation and social change. In our study, early life histories are constructed from multi-isotope and enamel peptide analysis of permanent first molars associated with Victorian era dental practices operating between AD 1881 and 1905 in Invercargill. Chemical analyses of the teeth provide insight into the childhood feeding practices, diet, and mobility of the people who had their teeth extracted.

MATERIALS AND METHODS

Four permanent left mandibular first molars were analyzed from a cache of teeth discovered at the Leviathan Gift Depot site during excavations in 2019. The methods used were: (1) enamel peptide analysis to assess chromosomal sex; (2) bulk (δ13 Ccarbonate ) and incremental (δ13 Ccollagen and δ15 N) isotope analysis of dentin to assess childhood diet; and (3) strontium (87 Sr/86 Sr) and oxygen (δ18 O) isotope analysis of enamel to assess childhood residency. Two modern permanent first molars from known individuals were analyzed as controls.

RESULTS

The archaeological teeth were from three chromosomal males and one female. The protein and whole diets were predominately based on C3 -plants and domestic animal products (meat and milk). A breastfeeding signal was only identified in one historic male. All individuals likely had childhood residences in Aotearoa.

DISCUSSION

Unlike most bioarcheological studies that rely on the remains of the dead, the teeth analysed in this study were extracted from living people. We suggest that the dental patients were likely second or third generation colonists to Aotearoa, with fairly similar childhood diets. They were potentially lower-class individuals either living in, or passing through, the growing colonial center of Invercargill.

The Mediterranean archive of isotopic data, a dataset to explore lifeways from the Neolithic to the Iron Age

We present the open-access Mediterranean Archive of Isotopic dAta (MAIA) dataset, which includes over 48,000 isotopic measurements from prehistoric human, animal and plant samples from archaeological sites in the Mediterranean basin dating from the Neolithic to the Iron Age (ca. 6000 - 600 BCE). MAIA collates isotopic measurements (δ13C, δ15N, δ34S, δ18O and 87Sr/86Sr) alongside supporting information (e.g. chronology, location and bibliographic reference). MAIA can be used to explore past human and animal diets and mobility, reconstruct paleo-ecological and -climatic phenomena and investigate human-environment interaction throughout later prehistory in the Mediterranean. MAIA has multiple research applications and here we show how it can be used to evaluate sample preservation and identify data gaps to be addressed in future research. MAIA is available in an open-access format and can be employed in archaeological, anthropological, and paleo-ecological research.

Epipalaeolithic animal tending to Neolithic herding at Abu Hureyra, Syria (12,800–7,800 calBP): Deciphering dung spherulites

Excavations at Abu Hureyra, Syria, during the 1970s exposed a long sequence of occupation spanning the transition from hunting-and-gathering to agriculture. Dung spherulites preserved within curated flotation samples from Epipalaeolithic (ca. 13,300–11,400 calBP) and Neolithic (ca. 10,600–7,800 calBP) occupations are examined here alongside archaeological, archaeobotanical, and zooarchaeological data to consider animal management, fuel selection, and various uses of dung. Spherulites were present throughout the entire sequence in varying concentrations. Using a new method to quantify spherulites, exclusion criteria were developed to eliminate samples possibly contaminated with modern dung, strengthening observations of ancient human behavior. Darkened spherulites within an Epipalaeolithic 1B firepit (12,800–12,300 calBP) indicate burning between 500–700°C, documenting early use of dung fuel by hunter-gatherers as a supplement to wood, coeval with a dramatic shift to rectilinear architecture, increasing proportions of wild sheep and aurochsen, reduced emphasis on small game, and elevated dung concentrations immediately outside the 1B dwelling. Combined, these observations suggest that small numbers of live animals (possibly wild sheep) were tended on-site by Epipalaeolithic hunter-gatherers to supplement gazelle hunting, raising the question of whether early experiments in animal management emerged contemporaneously with, or pre-date, cultivation. Dung was used to prepare plaster floors during the Neolithic and continued to be burned as a supplemental fuel, indicating that spherulites were deposited via multiple human- and animal-related pathways. This has important implications for interpretations of archaeobotanical assemblages across the region. Spherulite concentrations dropped abruptly during Neolithic 2B (9,300–8,000 calBP) and 2C (8,000–7,800 calBP), when sheep/goat herding surpassed gazelle hunting, possibly corresponding with movement of animals away from the site as herd sizes increased. As hunter-gatherers at Abu Hureyra began interacting with wild taxa in different ways, they set in motion a remarkable transformation in the ways people interacted with animals, plants, and their environment.

Child dietary patterns in Homo sapiens evolution: A systematic review

Dietary patterns spanning millennia could inform contemporary public health nutrition. Children are largely absent from evidence describing diets throughout human evolution, despite prevalent malnutrition today signaling a potential genome-environment divergence. This systematic review aimed to identify dietary patterns of children ages 6 months to 10 years consumed before the widespread adoption of agriculture. Metrics of mention frequency (counts of food types reported) and food groups (globally standardized categories) were applied to: compare diets across subsistence modes [gatherer-hunter-fisher (GHF), early agriculture (EA) groups]; examine diet quality and diversity; and characterize differences by life course phase and environmental context defined using Köppen-Geiger climate zones. The review yielded child diet information from 95 cultural groups (52 from GHF; 43 from EA/mixed subsistence groups). Animal foods (terrestrial and aquatic) were the most frequently mentioned food groups in dietary patterns across subsistence modes, though at higher frequencies in GHF than in EA. A broad range of fruits, vegetables, roots and tubers were more common in GHF, while children from EA groups consumed more cereals than GHF, associated with poor health consequences as reported in some studies. Forty-eight studies compared diets across life course phases: 28 showed differences and 20 demonstrated similarities in child versus adult diets. Climate zone was a driver of food patterns provisioned from local ecosystems. Evidence from Homo sapiens evolution points to the need for nutrient-dense foods with high quality proteins and greater variety within and across food groups. Public health solutions could integrate these findings into food-based dietary guidelines for children.

Raising girls and boys in early China: Stable isotope data reveal sex differences in weaning and childhood diets during the eastern Zhou era

OBJECTIVES

Using stable isotope analysis of incremental dentin segments, we reconstruct breastfeeding, weaning, and childhood dietary patterns of Eastern Zhou period (771-221 BC) individuals from the Central Plains of China. Previous isotopic research on the Eastern Zhou demonstrated dietary difference between male and female diets in adulthood via bone collagen analysis. To understand the development of gendered dietary patterns we must examine the early life period. We aim to identify the timing of the weaning process, whether childhood diets were the same as adulthood diets, and if there were differences between the diets of boys and girls during childhood.

MATERIALS AND METHODS

We present incremental dentin and bone collagen δ13 C and δ15 N isotope data from 23 individuals from two Eastern Zhou archaeological sites (Xiyasi and Changxinyuan ).

RESULTS

Weaning was completed between ages 2.5 and 4 years. Females were weaned slightly earlier than males. Early childhood diets show significant incorporation of C3 foods, such as wheat and soybean, for almost all children, while later adulthood diets indicate greater incorporation of C4 foods (millets), particularly for males.

DISCUSSION

Childhood diets included greater amounts of C3 foods than expected, suggesting that grains such as wheat may have been adopted in these communities as foods for children. Nevertheless, dietary differentiation between females and males began in childhood, with boys eating more millets (C4 foods) than girls. The findings suggest that feeding children was a significant aspect of socialization and cultural gendering of individuals in ancient China.

Those who died very young-Inferences from δ15 N and δ13 C in bone collagen and the absence of a neonatal line in enamel related to the possible onset of breastfeeding

OBJECTIVES

Stable isotope analysis has often been used in neonatal remains from archeological contexts to investigate the presence of a signal of breastfeeding and weaning in past populations. Tooth histology on the other hand might be used as an indicator of birth survival. This pilot study aimed to investigate the feasibility of using stable nitrogen (δ¹⁵ N) and carbon (δ¹³ C) isotope values from neonatal bone collagen to elucidate if values deviating from the adult female average could indicate breastfeeding and co-occur with the presence of a neonatal line (NNL). The combination of these independent indicators might be useful in clarifying the fate of individuals who died around birth.

MATERIALS AND METHODS

Bone collagen from 21 archeological human and animal specimens was extracted and analyzed via mass-spectrometry for δ¹⁵ N and δ¹³ C. A verification of the stable isotope results was undertaken using tooth histology on three individuals who were investigated for the presence of a NNL as an indicator of live birth and short survival.

RESULTS

The biological age of the human samples varied between 8.5 lunar months (Lm) and 2 postnatal months (Pm) of age. All except one individual exhibited elevated δ¹⁵ N values compared to the female average. The histological analyses revealed no NNL for this and two further individuals (n = 3).

DISCUSSION

The results indicate that elevated nitrogen values of very young infants relative to a female average in archeological contexts are not necessarily associated with a breastfeeding onset signal, and therefore cannot be used exclusively as a proxy of birth survival. The elevation might be possible due to various reasons; one could be nutritional, in particular maternal stress during pregnancy or a metabolic disorder of mother and/or her child. In those cases, the evaluation of a NNL might reveal a false breastfeeding signal as seen for two individuals in our sample who have elevated nitrogen values despite the fact no NNL could be observed. Overall, our data support the growing awareness that bone collagen δ¹⁵ N values of neonates/infants should not be used as a proxy for breastfeeding or birth survival on its own.

Let's talk about stress, baby! Infant-feeding practices and stress in the ancient Atacama desert, Northern Chile

AIMS AND OBJECTIVES

The transition to an agricultural economy is often presumed to involve an increase in female fertility related to changes in weaning practice. In particular, the availability of staple crops as complementary foods is hypothesized to allow earlier weaning in agricultural populations. In this study, our primary aim is to explore whether this model fits the agricultural transition in the Atacama Desert using incremental isotopic analysis. A secondary aim of this study is to identify isotopic patterns relating to weaning, and assess how these may be differentiated from those relating to early life stress.

MATERIALS AND METHODS

We use incremental isotopic analysis of dentine to examine changes in δ¹⁵ N and δ¹³ C values from infancy and childhood in sites of the Arica region (n = 30). We compare individuals from pre-agricultural and agricultural phases to establish isotopic patterns and relate these patterns to maternal diet, weaning trajectory and physiological stress.

RESULTS

We find that there is no evidence for systematic temporal or geographic variation in incremental isotopic results. Instead, results from all time periods are highly variable, with weaning completed between 1.5 and 3.5 years. Characteristics of the incremental profiles indicate that both in utero and postnatal stress were a common part of the infant experience in the Atacama.

DISCUSSION

In the Atacama Desert it appears that the arrival of agricultural crops did not result in uniform shifts in weaning behavior. Instead, infant and child diet seems to have been dictated by the broad-spectrum diets of the mothers, perhaps as a way of mitigating the stresses of the harsh desert environment.