The Study
Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information
This study looked at the chemical fingerprints in ancient animal teeth and found that meat-eaters, plant-eaters, and mixed-eaters had different patterns — like different colors in a paint palette. But it didn’t change what the animals ate to test if the pattern was caused by diet — it just noticed the pattern after the fact.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists studied ancient animal teeth from a cave in Laos to see what they ate by measuring zinc in their enamel, since the old protein in bones was gone.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 515 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This means we can now tell if ancient humans or animals ate mostly meat or plants even when bones are too old for protein tests.
- 2Carnivores had the lowest zinc levels (0.09‰), herbivores the highest (0.68‰), and omnivores were in between (0.41‰).
- 3Omnivores showed the most variation, meaning they ate both plants and meat.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Proceedings of the National Academy of Sciences of the United States of America
Year
2020
Authors
N. Bourgon, K. Jaouen, A. Bacon, K. Jochum, E. Dufour, P. Duringer, J. Ponche, R. Joannes‐Boyau, Quentin Boesch, P. Antoine, Manon Hullot, U. Weis, E. Schulz-Kornas, Manuel Trost, D. Fiorillo, F. Demeter, Elise Patole-Edoumba, L. Shackelford, T. Dunn, A. Zachwieja, Somoh Duangthongchit, Thongsa Sayavonkhamdy, P. Sichanthongtip, Daovee Sihanam, V. Souksavatdy, J. Hublin, T. Tütken
Related Content
Claims (7)
Throughout most of human evolutionary history, the diet of early human ancestors consisted mainly of animal-based foods, with meat being the main source of nutrition.
Between 1.2 million and a few hundred thousand years ago, early human ancestors like Homo and Neanderthals relied mainly on meat and other animal foods for nutrition, while earlier ancestors like Australopithecus ate mostly plants.
Analysis of zinc isotopes in ancient tooth enamel shows no link to carbon or oxygen isotopes that reflect diet type or climate conditions, meaning zinc isotopes can reliably indicate an organism's position in the food chain without being influenced by those other factors.
The zinc isotope signatures in ancient human teeth from Laos have remained unchanged since burial, because their chemical patterns match those of modern teeth and show no link to elements that typically enter bones and teeth after death, even though other organic material in the samples has degraded.
Analysis of zinc isotopes in fossilized teeth from ancient mammals in Laos reveals a predictable pattern: meat-eating animals have lower zinc isotope values than plant-eating animals, with herbivores showing the highest values. This pattern persists even after tens of thousands of years, indicating that zinc isotopes in tooth enamel can record dietary habits when other biological markers like collagen have disappeared.
Analysis of zinc isotopes in fossil teeth from Tam Hay Marklot cave shows that animals with mixed diets had the widest variation in zinc isotope levels, allowing scientists to identify which ancient species ate both plants and animals.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.