THE FUNDAMENTAL RELATIONSHIP BETWEEN ANCIENT DIET AND THE INORGANIC CONSTITUENTS OF BONE AS DERIVED FROM FEEDING EXPERIMENTS

The levels of ten elements (phosphorus, calcium, magnesium, strontium, barium, potassium, sodium, zinc, iron, and aluminium) have been measured in the femurs and humeri of laboratory rats grown on test diets as a model for palaeodietary studies of excavated human skeletons. High levels of dietary fibre correlate with lower Ca and higher Sr and Ba in the bone. High values of the dietary Sr/Ca ratio correlate with high Sr levels in the bone. High levels of dietary protein correlate with lower Sr and higher Zn. High values of the ratio Ba/Ca and lower levels of Fe correlate with higher levels of Ba. Because bone levels typically are controlled by several dietary components, variation of the levels of a given element in the diet does not necessarily translate into analogous variations in bone. Only K and Fe in bone correlate highly with their levels in diet. The failure of bone Sr, Ba, and Zn to correlate positively with dietary levels is fully explicable in terms of their interdependence on other dietary components, such as Ca, P, Fe, protein, and fibre.     

CHARACTERIZING THE DIET OF INDIVIDUALS AT THE NEOLITHIC CHAMBERED TOMB OF HAZLETON NORTH,GLOUCESTERSHIRE, ENGLAND,USING STABLE ISOTOPIC ANALYSIS*

Stable carbon and nitrogen isotope compositions were measured on human and faunal bones, sampled from the Neolithic chambered tomb of Hazleton North, Gloucestershire, UK. The values were used to characterize the diet of the burial community as a whole. Humans were higher in δ¹⁵N by 4.5–5.0‰ relative to animal δ¹⁵N, from which we conclude that, based on currently accepted interpretations of isotopic data, the humans consumed a diet that was very high in meat or animal products (75% by weight of protein). Comparison was also possible between cortical and cancellous femoral collagen, with the results showing no significant difference for the adult humans. The sample of human isotopic values showed little variability, in contrast to that found in the domestic and wild animals from the site (including cattle, pigs, sheep and deer). We suggest that this is due to local environmental differences, rather than to environmental change over time or physiological differences between individual animals, and that this pattern is likely to hold for many other archaeological sites when analysed with sufficient statistical weight.     

Last Meals: Recovering Abdominal Contents From Skeletonized Remains

Excavation and analysis of human remains is becoming a polarized field in anthropology; it is therefore necessary to consider alternate avenues of data collection from these features to maximize their potential. The analysis of abdominal soils for digestive tract contents is consistently overlooked in research designs. Two previous studies have attempted to recover abdominal contents through systematic sampling methods using multiple inhumations and two others have recovered colon contents in isolated instances. This research briefly familiarizes the reader with current state of investigation, and then proposes and tests a different method to recover abdominal contents in skeletonized inhumations. Using this method, more than 70% of the sampled inhumations yielded data on ingested botanical products. Though recovered, faunal remains were rare. The implications of recovery, some interpretations for each population, and avenues of future research are considered.     

Infrared and Isotopic Evidence for Diagenesis of Bone Apatite at Dos Pilas, Guatemala: Palaeodietary Implications

The use of stable carbon isotopic analysis of bone apatite to reconstruct prehistoric diets is hindered by the possibility of diagenetic alteration of carbonate during burial. We examine apatite preservation in Classic Period Maya skeletal remains from Dos Pilas, Guatemala, using Fourier transform infrared spectroscopy (FTIR). We use weight % CO₂evolved from apatite, FTIR carbonate/phosphate absorbance ratios, phosphate peak splitting crystallinity indices, fluoride peaks, and stable oxygen isotopic ratios to identify diagenetic change in apatite chemistry. Isotopically light carbon taken up from burial soil is adequately removed from most Dos Pilas bone by treatment with dilute acetic acid, but more severe alteration cannot be reversed by standard preparation methods. Infrared criteria identify recrystallized apatite in a subset of Dos Pilas burials, that is accompanied by isotopic exchange, and that no longer preserves biogenic δ¹³C. These results illustrate that comparatively recent bone may be diagenetically altered and demonstrate a need for systematic evaluation of mineral integrity in all archaeological bone prior to interpreting paleodiets with apatite δ¹³C.     

EFFECTS OF DIFFERENT SAMPLE PREPARATION METHODS ON STABLE CARBON AND OXYGEN ISOTOPE VALUES OF BONE APATITE: A COMPARISON OF TWO TREATMENT PROTOCOLS*

Researchers have long debated the appropriateness of stable isotope analysis of bone apatite to reconstruct the diets of ancient animals. The debate has centred, in part, on diagenesis of bone mineral from interaction with the burial environment. A number of acetic acid treatments are used to remove diagenetic carbonates from samples; however, less is known on how different protocols alter stable isotope values. We compare two common acetic acid solution treatments (0.1 M versus 1.0 M-buffered) to examine the effects on carbon and oxygen isotope values and Fourier transform infrared spectroscopy (FTIR) spectra in human bone from different burial contexts. Results indicate that both treatments have a similar effect on isotope values and FTIR spectra in bone apatite.     

Isolation and Isotopic Analysis of Individual Amino Acids from Archaeological Bone Collagen: A New Method Using Rp‐hplc

This paper presents a new method for the isolation and isotopic analysis of some individual amino acids from proteins. The technique and its constituent steps are discussed; then isotopic analyses of amino acids from several samples of bone collagen from the Late Roman site of Poundbury, Dorset, UK are presented. The applications of the method are discussed, as well as some advantages of this technique relative to other methods. Although developed for use with archaeological bone collagen, the technique is equally applicable to other proteinaceous materials. The use of reversed‐phase HPLC avoids problems of isotopic fractionation inherent in using ion‐exchange HPLC. Amino acids are isolated preparatively, allowing both carbon and nitrogen isotopic values to be measured on a single sample using CF‐IRMS. Since amino acids are isotopically analysed in an underivatized form (unlike GC‐C‐IRMS), the method also presents the possibility of collecting the CO₂ generated during CF‐IRMS: this would allow the subsequent dating by ¹⁴C‐AMS of individual amino acids isolated from archaeological samples.