Deciphering Neanderthal Diets: The Zinc Conundrum
Unlocking the Mystery Behind Neanderthal Dietary Habits
The question of what Neanderthals consumed has long intrigued scientists, unearthing a paradox within their dietary habits. Recent research delves into this enigmatic aspect of our ancient relatives, spotlighting the conundrum surrounding their supposed carnivorous inclination and raising new puzzling findings.
Over the last two million years, human ancestors have exhibited omnivorous tendencies, albeit with a prominent carnivorous streak. However, the case of Neanderthals stands as a peculiar riddle in the annals of dietary science.
Previous analyses of Neanderthal remains, such as the 2022 study1 led by Klervia Jaouen at the Max Planck Institute for Evolutionary Anthropology, have consistently indicated a high proclivity for carnivorous consumption. Yet, this notion seems contradictory, considering certain physiological limitations.
Unlike obligate carnivores such as cats, which solely derive sustenance from meat due to their inability to digest carbohydrates, humans thrive on a varied diet. However, excessive reliance on lean meat—beyond 35 to 40 percent of caloric intake—can lead to severe health consequences due to the body's inefficiency in eliminating excess nitrogen, a byproduct of protein digestion.
The enigma deepens with the examination of a specific Neanderthal in Gabasa, Spain, residing 50,000 years ago. In a follow-up study2 published in PNAS by Dr. Miki Ben-Dor and Prof. Ran Barkai from Tel Aviv University, the research spotlights the overlooked role of fat in early human nutrition—an aspect supported by the original study's authors.
While past studies have conjectured Neanderthals' adaptability to digest meat more effectively than modern humans, questions linger about the extent of their carnivorous inclination. The zinc-66 isotopic ratio found in the Gabasa Neanderthal's teeth presents a perplexing anomaly, surpassing even that of obligate carnivores.
The zinc isotopic ratio in teeth offers insights into dietary preferences. Herbivores, accumulating zinc-66 from plants, experience varying losses during digestion, which further diminishes in subsequent carnivorous consumption. This process typically aligns with omnivorous diets but contradicts the Neanderthal findings.
While proposed explanations point to metabolic peculiarities or mammoth-centric diets affecting the zinc and nitrogen readings, certain inconsistencies challenge these theories. The scarcity of mammoth remains at Neanderthal sites raises questions about the veracity of this hypothesis.
The latest research underscores the role of fat in early human sustenance, suggesting that Neanderthals potentially derived a substantial portion of their calories from fat-rich animal sources. This revelation not only supplements their diet but offers a plausible explanation for their survival amidst dwindling megafauna populations.
The dwindling megafauna in Europe around 40,000 years ago aligns with the Neanderthal decline, indicating a possible dependency on the fat reserves of these creatures for survival.
As the puzzle of Neanderthal diets unfolds, the significance of fat in their nutritional intake emerges as a pivotal factor. Though the exact dietary composition of Neanderthals remains elusive, the synergy between meat consumption and fat intake appears crucial to their survival, underscoring the complex interplay between ancient hominins and their dietary evolution.
The quest to unravel the enigmatic dietary habits of our ancient relatives continues, prompting further inquiry into the nuanced nutritional strategies adopted by Neanderthals to navigate changing ecosystems.
Jaouen, K., Villalba-Mouco, V., Smith, G. M., Trost, M., Leichliter, J., Lüdecke, T., Méjean, P., Mandrou, S., Chmeleff, J., Guiserix, D., Bourgon, N., Blasco, F., Mendes Cardoso, J., Duquenoy, C., Moubtahij, Z., Salazar Garcia, D. C., Richards, M., Tütken, T., Hublin, J.-J., … Montes, L. (2022). A Neandertal dietary conundrum: Insights provided by tooth enamel Zn isotopes from Gabasa, Spain. Proceedings of the National Academy of Sciences of the United States of America, 119(43). https://doi.org/10.1073/pnas.2109315119
Jaouen, K., Tütken, T., Bourgon, N., Lüdecke, T., Smith, G. M., Salazar-García, D. C., Hublin, J.-J., Villalba-Mouco, V., & Méjean, P. (2023). Reply to Ben-Dor and Barkai: A low Zn isotope ratio is not equal to a low Zn content. Proceedings of the National Academy of Sciences of the United States of America, 120(6). https://doi.org/10.1073/pnas.2218491120