Tooth plaque reveals what Neanderthals ate

By investigating the plaque left behind on the teeth of Neanderthals from 48,000-50,000 years ago, paleontologists have uncovered a wealth of knowledge about their diets, lifestyles and even their knowledge of medicine. In an unprecedented study into the plant based components of their diet, researchers say it could also have big implications for understanding the evolution of modern human diets and how our own bacterial components have evolved.

Remains from two locations, Spy in Belgium and the El Sidrón cave in Northern Spain, were studied and found to have had remarkably different diets. An analysis of the mineralised plaque, known as dental calculus, from the Belgian neanderthal showed evidence of a heavily carnivorous diet with traces of wooly rhino and wild sheep DNA. By contrast, the dental calculus from the Spanish remains showed evidence of a heavily plant based diet featuring pine nuts, moss and wild mushrooms.

The latest discovery marks a new step in understanding the plant based diets of neanderthals, which were surprisingly diverse. Since plant matter does not leave any remains, unlike animal bones found near neanderthal remains, the only way to infer what vegetation they ate is from the genetic analysis of dental calculus, a technique that has only come into its own in recent years, 30 years after dental calculus was first investigated. This was crucial in determining another surprising finding from the study, namely that one neanderthal shows evidence of having treated a bacterial infection in his tooth by eating plants with medicinal properties.

“We had evidence of a dental abscess which would have been very painful. So this individual was pretty sick, and in that individual we found evidence for plants that aren’t normally part of the diet. They’re more related to medicinal purposes, such as poplar. The bark or leaves of poplar contain the main components of aspirin. Furthermore, there was evidence of the consumption of fungi that was penicillin-like with antibiotic properties. Since that was only in this individual, it potentially suggests that these individuals had knowledge of medicinal plants and were even self medicating,” says Keith Dobney from the University of Liverpool, one of the lead authors on the study.

The study fits into a growing body of evidence that suggests that the common perception of neanderthals as having been “knuckle-dragging cavemen” is far from the truth. In fact, as the most recent, extinct relatives of human beings, they demonstrated remarkably sophisticated behaviour. Furthermore, having been in contact with early, modern humans for several millennia, they mated with and exchanged DNA with our ancestors, so that their DNA lives on inside us today. This intermingling of human and neanderthal history opens a window into the evolution of our own microbiomes and health.

“To be able to track the evolutions of pathogens and microbiomes that have evolved with us and our most recent ancestors will be relevant to the major work going on, on modern day microbiomes. Clinicians have realised just how important for our health these ecosystems in our stomach and our mouths are, so if we can track them in time and space, we have a new window to help understand [modern health issues]. Obesity and diabetes haven’t just sprung up out of nowhere, there have been major changes to our diets and the way we’re living and we can track that now in a new way.”

Based on such considerations, the so-called paleo diet is becoming increasingly popular. The idea is that since our early hunter-gatherer ancestors subsisted on a diet of mostly meat and vegetation, the switch to a carbohydrate-heavy diet is out of synch with the evolutionary needs of our body. To be healthy, proponents of the paleo diet say we need to revert back to a diet that cuts out the carbs and swaps in more meat, fruit and veg. But Dobney indicates there’s a lot of misinformation surrounding that idea.

“The idea of the palaeodiet is a faddy modern construct not based on good scientific data to back it up. However, it’s clear that increased carbs and sugar have had a significant impact on our microbiome and therefore our overall health and we’re now in a position to explore this properly.”