Archaeologists studying human remains from El Portalón, a cave site in Atapuerca, Spain, have uncovered surprising details about how prehistoric communities lived, ate, and evolved. Instead of relying only on bones or artifacts, the researchers analyzed hardened dental plaque—also called calculus—taken from individuals who lived thousands of years ago. Though it may look like nothing more than grime on teeth, this fossilized buildup is an incredible archive of information.
The calculus preserved fragments of DNA and proteins from food, bacteria, and even the environment. By carefully extracting and sequencing these traces, the scientists reconstructed aspects of ancient diets, health, and cultural practices. For instance, the team found proteins from cereals such as wheat and barley, along with legumes like peas and lentils. This shows that farming communities in prehistoric Iberia were cultivating and consuming a range of crops, much like modern diets but at the dawn of agriculture.
Milk proteins were also detected, providing evidence that people in this region were herding animals and using their milk. This is especially interesting because many early farmers could not digest lactose as adults. The fact that they consumed dairy suggests that cultural practices—like fermenting milk into cheese or yogurt—helped make it digestible before genetic adaptations for lactose tolerance became widespread.
The plaque also held remnants of oral bacteria. Some were friendly microbes still common in mouths today, while others were linked to gum disease and infections. This highlights that oral health challenges we face now—like cavities and inflammation—were already affecting people thousands of years ago. In addition, the discovery of plant micro-remains and traces of pigments suggests that daily activities, including toolmaking or using colored minerals, left microscopic signatures in their mouths.
Altogether, the findings reveal that dental calculus is more than a medical nuisance—it’s a powerful archaeological resource. It captures details of what people ate, how they interacted with animals and crops, and what microbial companions lived with them. The study from El Portalón paints a vivid picture of early Iberian farming communities: people who balanced a diverse plant-based diet, experimented with dairying, and faced the same microbial battles we do today.
By peering into this unexpected archive, scientists are filling in missing pieces of the human story—one tooth at a time.