| Abstract: |
pg 541-543 result from metabolism and physiology, and those that occur in archeological samples after burial. (1) The menu of edible items is provided by archeological investigations. This menu is constructed from preserved food remains. Most studies have analyzed macroscopic remains such as fragments of bone, parts of plants, pollen, and the like. However, food remains may also be preserved at the molecular Level, e.g., various fats or diagnostic proteins (Röttlander and Schlichtherle 1979). Pictorial representations of menu items are a rare source of information
indirect sources of information include technological and stylistic changes in artifacts and changes in settlement patterns. Archeological studies arc based upon discards and tangible products or remnants of group behavior. Archeological studies of the food system are generalized in time and diffused in space. There is an inherent lack of detail
for example, archeological studies cannot tell us which food parts were considered as essential. Nor can it be determined which members in the population consumed how much of specific items. However, despite the limitations of the archeological record, interpretations of diet on this basis are accurate. Analysis of the nutritional quality and energy produced by specific items (with implications for changing biological or cultural patterns) is possible through archeological remains. (2) The meal is the process by which individuals select certain items from the culturally circumscribed environment (i.e., the menu). These selected items can be characterized by their chemical values (isotopic ratios and/or elemental concentrations). The meal transfers the extrasomatic chemical environment into the internal organism. This transfer occurs as "food", which cannot be measured chemically. Aspects of meal preparation such as the ingredients (via 13C values) or coing temperatures (via electron paramagnetic resonance, cf. Hillman et al 1983) can be measured from preserved meal remains. The results of meal selection can be measured through the chemical analysis of human remains. Of course, the biological and cultural processes of the meal itself-what is food, when is it served, with whom it is eaten-are not detectable in prehistory. Although not indicated in Figure 1, the meal is the component that principally defines the other components of the diet system. (3) The archeological midden records the remains of the skeletal population's diet system but is not a part of the system. The midden material (allowing for transformation processes of archeological record formation) is the basis for menu interpretation. The midden is also the postmortem environment of the sample material we analyze. The processes of decomposition, transport, stability, concentration, exchange, etc. that alter the chemical record of the once-living organism are not well understood. Pg 544 However, the diet model reminds us the that dietary reconstruction derived from the archaeological data base on the preserved food remains of patterns of cultural remains is a construction of the menu. Even when the archaeological diet reconstruction is transposed into a chemical measure (such as -value), DeNiro and Epstein 1981), the menu is still not equivalent to the chemical value of the bone sample. The latter is the integrated average of dietary consumption. Because the menu and the meal are different entities, it is difficult to evaluate one in terms of the other. The relationship between food refuse (macro remains and actual food consumption and that between the tissue chemical measurement and a diet composition measurement (such as kJ or volume) are unknown
therefore we do not know if an archaeological or biological reconstruction (including chemical assay) is a more accurate or useful approach. The isotopic and elemental concentrations in human bone are not a direct measure of dietary items. Meal preparation alters the chemistry of the original food items (Kuhnlein and Calloway 1979). Individual metabolism- the digestion of foods and synthesis and catabolism of tissues- alters the chemical content after the meal is ingested. Although the skeleton is a product of a lifetime, it is not static. Adult human bone provides a chemcial record of approximately the last 10 years of life. Teeth primarily reflect the chemistry of early childhood, but they too are not chemically intert tissues. pg 545 The chemistry of the archaeological bone when analyzed is not the same as when it was buried. Anthropology has not developed bone chemical analysis procedures like those used for hair analysis. \b[Good figure on the sequence fo chemical analysis (modified from Bumstead 1980)\b Elemental concentrations vary between bone fractions. Pg 546 There is evidence that the photosynthetic pathway of a plant is correlated with differential uptake or composition of various elements (Smith and Bouton 1981). does not actually measure the absolute abundance of dietary items. The matrix for isotopic analysis is demineralized, water-soluable mix of soil carbon compounds and remnant bone proteins, some of which are derived from collagen. Fortunately, complete separations of soil and bone protein is not required in any case where the contributing soil isotopic ratio does not differ from that of bone sample or where purification has proceeded to the extent that contamination cannot be detected (Bumsted 1984). Pg 547 Bone from adults is less susceptible to degradation than bone from children because of greater molecular crosslinking and mineralization with age. Though many variables contribute to the variation in isotopic composition, stable carbon istopic analysis can distinquish when cultivated cereals have been added to a C\-3\- diet in excess of 20% of the C\-3\- diet's isotopic abundance: a difference in the isotopic values of greater than 5. Elemental variation in contemporary bone and teeth also shows a lognormal or square-root distribution (Bowen 1979
Brätter et al 1977). Much of the elemental variation is due to environmental factors (Curzon and Cuttress 1983
Passwater and Cranton 1983
National Academy of Sciences 1974). The anomalous distribution suggest tissue concentrations of elements and isotopes are not in a linear or additive relationship to the dietary intake. Chemical analysis gives a quantitative estimate of the average relative portions of major food groups in the diets of prehistoric individuals, yet the analysis cannot tell us how much food there was. Data of seasonality and abundance will be derived from the archaeological studies. Paleoepidemiological and paleophysiological data are required to determine if the amount and quality of the diet were sufficient to meet changing biological needs of the population. We do not know the specific relationship between the primary, emic definition of a meal, the dietary composition of chemical measurement, the nutritional evaluation of pathological assessment, and the menu revealed by its ultimate macro- and artificial remains. Pg 550 delta -value of stable isotopic assay or p.p.m. of elemental determination can be used to identify chemical classes of prehistoric diet. However, analytical data can be used to generate significant information about human adaptation and biological variation when used with paleoecology analysis and skeletal paleopathology. We should examine patterns of chemical variation within the anthropological parameters of a population ecology approach.
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