The study says that seaweed was a staple food for ancient Europeans

(CNN) — Algae and aquatic plants, virtually absent from most Western diets today, were a staple food for ancient Europeans, analysis of molecules preserved in fossilized dental plaque reveals.

According to the study published Tuesday in the academic journal Nature Communications, evidence of this taste for nutrient-rich plants and algae, which had been hidden until now, has been difficult to discover in archaeological records. Previously, when researchers discovered evidence of algae, they interpreted their presence as fuel, food packaging, or fertilizer.

Previous research has suggested that the introduction of agriculture, which began about 8,000 years ago, caused ancient humans to largely stop eating seaweed. In Europe, in the 18th century, seaweed was considered food for periods of hunger or only suitable for feeding livestock.

“It is very exciting to be able to demonstrate that seaweeds and other native freshwater plants were eaten over a long period of our European past,” study author Karen Hardy, a professor of prehistoric archeology at the University of Glasgow, said in a press release.

Dental plaque can reveal a lot about ancient diets. Credit: Karen Hardy

“The link between food and the sea”

Hardy and a team of archaeologists from the University of Glasgow and the University of York in the UK examined the teeth of 74 early humans discovered at 28 archaeological sites across Europe, including the northernmost parts of Scotland, southern Spain and Lithuania.

The oldest sites examined in the study in Spain and Lithuania date back more than 8,000 years, while the most recent ones are about 2,000 years old.

The researchers were able to detect identifiable chemical markers in dental calculus, the accumulation of bacterial debris and food residue on teeth over time, in 37 samples belonging to 33 individuals. 26 of them revealed that the menu was made up of algae or aquatic plants.

“Dental plaque is very common, and once it appears, it can only be removed by scraping. This is what dentists do as part of the cleaning process today,” Hardy explained via email.

“But in the past, they would accumulate, especially in the small gap between the tooth and the gum. They are common in most archaeological skeletal materials from throughout the past,” Hardy added. “It acts as a trap for substances that enter and pass through the mouth. Since it is present in the mouth, all substances within it are unambiguously linked to ingestion.”

Seaweeds, freshwater algae and aquatic plants have a “distinctive, unusual and complex organic chemistry” that allows for the preservation and detection of “highly resistant biomarkers” of three types of organic compounds: lipids, amino acids and alkylpyrroles, according to the study.

“It is the special combination of biomarkers that allows us to identify algae and aquatic plants,” Stephen Buckley, co-author of the study and a researcher in the Department of Archaeology at York University, says via email.

“Other plants have their own distinct biomarkers, but they do not tend to survive as well in archaeological contexts compared to algae (e.g., kelp, macroalgae), so we can say that kelp and aquatic plants were ingested and thus consumed, but we do not You necessarily get a complete picture of all foods consumed, which may depend on the prevailing environmental conditions.

Analysis of the samples showed that ancient people ate, or at least chewed, red, green and brown algae and a variety of freshwater aquatic plants, such as species of pond algae and plants of the same genus as water lilies.

“This strongly suggests that the nutritional benefits of seaweed were understood well enough by these ancient populations that they could maintain their nutritional connection to the sea,” Buckley said.

Among the remains studied, those found in cairns or graves in Orkney, an archipelago of islands off the coast of Scotland, revealed biomolecular evidence of the consumption of seaweeds, including carnabrassica, which is most likely a seaweed.

The study suggests that it wasn’t just coastal communities that ate seaweed. At La Coruna, a site in southeastern Spain that was occupied between 6059 and 5849 BC, algae were part of the diet despite being 80 kilometers from the coast.

Buckley added that it was not possible to tell whether the seaweed was cooked or eaten raw.

But he said it is plausible that seaweed is a staple food given its nutritional benefits and ease of obtaining it at the seashore.

Called “superfoods,” about 145 species of seaweed are consumed today, especially in Asia, and are known to have many health benefits.

The scientists said they hope their research will highlight the possibility of including more seaweeds and freshwater plants into current diets.