Ancient Maya diet: as inferred from isotopic and elemental analysis of human bone

Samples of human bone from the Lowland Maya site of Lamanai, Belize have been analysed for the trace elements Sr, Mg, and Zn and for δ15 N and δ13 C of collagen, in order to test various models of diet over the time range from pre-Classic (1250 bc to 250 ad) to Historic (1520 ad to 1670 ad) periods. The content of maize in the diet is inferred from δ13 C which is, in turn, negatively correlated with both Sr and Zn content. Maize constitutes about 50% of the diet in the oldest pre-Classic samples, decreases in importance to a minimum of about 37% in Terminal Classic times and subsequently rises to about 70% of the total diet in post-Classic times. The δ15 N of collagen remains essentially constant over this 2000 year period [9·9 ± 0·9 per mil (‰)], indicating essentially no change in the balance of protein sources, dominantly from wild and domesticated animals. N15 enrichment in a tomb burial suggests consumption of sea-foods by very high-status males. The results are discussed in the light of theories of collapse of the Maya society and ecological changes occurring at the site.