New Research Reveals Key Role of Olive Oil in Ancient Roman Diets

An essen­tial ingre­di­ent and an unmatched tool to pre­serve food­stuff, olives and olive oil played a cen­tral role in the days of ancient Herculaneum in what is today Naples.

Now, research has con­firmed that aver­age olive oil con­sump­tion for each inhab­i­tant could reach up to 20 liters per year.

“It was the main source of fat for them and it was widely used to store sea­sonal food to eat at a later date,” Silvia Soncin, a bioar­chae­ol­ogy researcher at the University of York and lead author of the study, told Olive Oil Times.

“Olives were abun­dant in the whole area and offered [locals] about 20 per­cent of their daily calo­rie intake,” she added.

However, this all ended on August 24, 79 C.E. when Mount Vesuvius inter­rupted its cen­turies-long dor­mancy and under­went one of the most destruc­tive erup­tions in human his­tory.

In 30 hours, its vio­lent out­break buried the nearby towns of Pompeii, Stabiae and Herculaneum under four cubic kilo­me­ters of burn­ing pumice and hot ashes.

Of the 2,000 Romans who per­ished in the vol­canic dis­as­ter, more than 300 tried to sur­vive by flee­ing to the Herculaneum beach. There, on the beach­front and in nearby stone vaults, they were enveloped by a 500 ºC gas dis­charge that quickly killed them and vapor­ized their tis­sues.

Many skele­tons of the vic­tims found on the site helped researchers in their effort to inves­ti­gate exactly what hap­pened and what their ear­lier life was like.

The lat­est research on those well-pre­served bones went even deeper and offered new clues to the role of olive oil in the diet of the Herculaneum res­i­dents at the time.

According to the researchers, the key to the new find­ings was the tech­nique that deter­mines the sta­ble iso­tope val­ues of amino acids from bone col­la­gen. Deploying Bayesian mod­els that incor­po­rate knowl­edge of pro­tein syn­the­sis, researchers had the chance to iden­tify with unprece­dent­edly high res­o­lu­tion the diet of 17 adults.

“We made a ten­ta­tive approach to deter­mine olive oil intake, we really wanted to see how far we could go with our method­ol­ogy,” Soncin said. ​“The chal­lenge is due to the fact that the bone col­la­gen analy­sis mostly high­lights the pro­tein por­tion while we had to focus on fatty acids.”

The researchers then focused on a few amino acids, which the human body processes when deriv­ing from macro-nutri­ents such as olive oil.

Researchers believe that males used to eat 50 per­cent more seafood than females. Proteins were obtained by men mostly from cere­als, while females ate more ani­mal prod­ucts, veg­eta­bles and fruits.

“The high-res­o­lu­tion tech­nique allowed us to focus on the con­sump­tion of four major food cat­e­gories: cere­als, ani­mal meat, fish and olive oil,” Soncin said.

The sci­en­tists believe that most fish­ing and mar­itime activ­i­ties were done by males. They were the ones to occupy the most priv­i­leged posi­tions in soci­ety and, as slaves, were freed at an ear­lier age.

“If com­pared to meat, fish and cere­als, olive oil com­prised almost one-fourth of food over­all con­sump­tion,” Soncin said. ​“It might seem a lot when com­pared to today’s con­sump­tion quan­ti­ties, but our find­ings coin­cide with what Romans his­to­ri­ans, such as Pliny, wrote and what mod­ern Roman econ­omy his­to­ri­ans believe.”

Soncin also cited pre­vi­ous stud­ies, such as that of Erica Rowan from Oxford University, which focused on Herculaneum’s waste and sewage sys­tems.

“So many olive dru­pes were found car­bonized there, which hints at the fact that the res­i­dents used olive branches to fuel the fire, which also tells us how abun­dant the olive tree was in the area at the time,” Soncin said.

The sci­en­tists said that Herculaneum res­i­dents used to eat more fish and seafood than adher­ents of a Mediterranean diet con­sume, in which ani­mal prod­ucts play a more rel­e­vant role.

“The remains… offer a unique oppor­tu­nity to exam­ine the lifestyles across an ancient com­mu­nity who lived and died together,” said Oliver Craig, the direc­tor of the university’s bioar­chae­ol­ogy pro­gram. ​“Historical sources often allude to dif­fer­en­tial access to food­stuffs across Roman soci­ety but rarely pro­vide direct or quan­ti­ta­tive infor­ma­tion.”

“We found sig­nif­i­cant dif­fer­ences in the pro­por­tions of marine and ter­res­trial foods con­sumed between males and females, imply­ing that access to food was dif­fer­en­ti­ated accord­ing to gen­der,” he added.

According to the university’s bioar­chae­ol­ogy depart­ment, the new approach ​“pro­vided dietary data of suf­fi­cient pre­ci­sion for com­par­i­son with assess­ments of food sup­ply to mod­ern pop­u­la­tions, open­ing up the pos­si­bil­ity of bench­mark­ing ancient diets against con­tem­po­rary set­tings where the con­se­quences for health are bet­ter under­stood.”

• Science Advances
• EurekAlert!
• Italian National Institute of Geophysics and Volcanology