Neanderthals, often depicted as primitive meat-eaters, are receiving a blow to their popular image with a groundbreaking new study. The research, which analyzed bacteria collected from Neanderthal teeth, reveals that our close cousins consumed a significant amount of roots, nuts, and other starchy foods. This dietary preference had a profound impact on the composition of the bacteria in their mouths. The findings suggest that Neanderthals, as well as our human ancestors, had adapted to consuming starch-rich foods as early as 600,000 years ago. This adaptation coincided with the need for increased sugar intake to fuel the expansion of their brains.
The growth of our ancestors’ brains doubled in size between 2 million and 700,000 years ago. Previously, researchers attributed this growth to improved stone tools and cooperative hunting, as a higher-quality diet of meat provided more energy to support brain development. However, the question remained as to how meat fulfilled this role since it is not a good source of glucose, a necessary energy source for brain growth.
The study conducted by molecular archaeologist Christina Warinner of Harvard and the Max Planck Institute for the Science of Human History, along with a large international team, aimed to investigate whether changes in diet or the environment could be tracked through oral bacteria. They examined the oral bacteria on the teeth of Neanderthals, preagricultural modern humans, chimps, gorillas, and howler monkeys. By analyzing billions of DNA fragments from ancient bacteria, they discovered a strong resemblance in the communities of bacteria between preagricultural humans and Neanderthals. Both groups harbored a distinctive group of Streptococcus bacteria in their mouths. These bacteria possessed the ability to bind to amylase, an enzyme abundant in human saliva that breaks down sugars from starchy foods. The presence of these strep bacteria indicated a higher consumption of starchy foods by Neanderthals and ancient modern humans compared to chimps.
Furthermore, the study suggests that these streptococci bacteria were inherited from a common ancestor of humans and Neanderthals, who lived over 600,000 years ago. While previous studies had already indicated that Neanderthals consumed grasses, tubers, and cooked barley, this research provides additional evidence that their starch-rich diet significantly influenced the composition of their oral microbiomes.
The implications of this study extend beyond diet. The efficiency of the amylase enzyme in digesting cooked starch rather than raw starch suggests that cooking may have been a common practice as early as 600,000 years ago. This finding raises questions about when cooking became prevalent, either during the initial expansion of the big brain nearly 2 million years ago or during a subsequent surge of growth.
The study introduces a novel approach to detecting major shifts in diet, according to geneticist Ran Blekhman of the University of Minnesota. In the case of Neanderthals, it underscores the importance of plants in their diet, challenging the notion that their food sources were primarily meat-based. Modern hunter-gatherer societies also rely significantly on gathering for a substantial portion of their caloric intake, reinforcing the relevance of plant components in human nutrition.
Overall, this research provides compelling evidence that Neanderthals and our ancient ancestors adapted to consuming starchy foods long before the advent of agriculture. It sheds light on their dietary preferences, the role of plants in their nutrition, and the potential significance of cooking in human evolution.