| Abstract: |
Uses the Sr/Ca method to make an inference on the age weaning from a sample population from a medieval Arab graveyard located on the eastern Mediterranean coast. A reduction in weaning-age is associated with shifts from nomadic, hunting and gathering economies to sedentary, agricultural ones. The rational for using Sr/Ca as a measure of dietary supplementation derives as follows: 1) Sr/Ca of human milk is generally very low due to discrimination in the both the mother intestinal tract and mammary gland. 2) Sr/Ca of solid food is relatively high 3) The relationship between dietary and skeletal Sr/Ca ratios is reasonably well established. 4) I contrast to adults, the gastro-intestinal tract of infants discriminates poorly against strontium after 1 year of age. With these in mind then, these observations suggest that, when plotted as a function of age, increasing Sr/Ca ratios in the bones of juveniles can be related to increased dietary Sr/Ca, presumably from the introduction of foods other than human milk in the diet. By accounting for changes in the level of discrimination that occur during growth and development, it is possible to infer dietary Sr/Ca values. The level of discrimination is commonly calculated as the Observed Ratio (OR): Sr/Ca production รท Sr/Ca precursor = OR In theory then, the calculated values of completely weaned individuals would be indistinguishable from that of adults. Results indicate a clear increase is discernible in the Sr/Ca ratio of calculated diets from infancy to the age of 1.5 years. By this age, we infer that the diet has not yet achieved a Sr/Ca value comparable to that of adults.
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