Olive Tree Emerges as Symbol of Interconnected Health and Sustainability

Summary

A new review study high­lights the inter­con­nected ben­e­fits of olive cul­ti­va­tion for human health, ani­mal health, and the envi­ron­ment, align­ing with the ​“One Health” approach. The study empha­sizes the role of olive trees in car­bon seques­tra­tion, soil health, and bio­di­ver­sity, as well as their impact on human health through olive oil con­sump­tion, while also show­cas­ing the poten­tial of olive by-prod­ucts in cre­at­ing a sus­tain­able cir­cu­lar econ­omy.

A new review study placed the olive crop at the cen­ter of a mod­ern vision for sus­tain­abil­ity and human well-being.

According to the researchers, the unique inter­con­nec­tion between human health, ani­mal health, and the envi­ron­ment that the olive tree and its cul­ti­va­tion engage rep­re­sents a valu­able oppor­tu­nity to explore and apply the ​“One Health” approach.

“One Health is really about think­ing of our exis­tence as an inte­grated sys­tem,” said Tassos Kyriakides, assis­tant pro­fes­sor of bio­sta­tis­tics at the Yale School of Public Health and co-author of the study. ​“Human health, ani­mal health and the envi­ron­ment are not sep­a­rate silos. They are deeply inter­con­nected,” Kyriakides explained.

One Health rep­re­sents a grow­ing field of research, col­lab­o­ra­tion and pol­icy action grounded in a holis­tic under­stand­ing of today’s inter­con­nected con­di­tions.

“This is not about say­ing, here’s human health, we’ll worry about these things, and here’s ani­mal health, and then the envi­ron­ment is some­thing else,” Kyriakides said. ​“It’s about rec­og­niz­ing that we’re all con­nected. If some­thing hap­pens in the envi­ron­ment, it affects humans, it affects ani­mals and then it’s a cycle.”

According to the authors of the review pub­lished in Frontiers in Public Health, the olive tree affects all the dimen­sions con­sid­ered by One Health.

Environmentally, olive groves act as car­bon sinks.

“It’s an ever­green tree. It takes car­bon diox­ide and puts it in the soil where it belongs,” Kyriakides explained.

According to the research, olive trees help mit­i­gate cli­mate change through the process of car­bon seques­tra­tion, which involves not only their bio­mass but also the sur­round­ing soil. As peren­nial plants, olive trees absorb car­bon diox­ide over long peri­ods of time. Especially when com­bined with sus­tain­able prac­tices and the re-use of by-prod­ucts, olive groves can sequester large quan­ti­ties of car­bon diox­ide.

The review found that they can store approx­i­mately 2.2 met­ric tons of car­bon per hectare per year. Those fig­ures com­pare with the 1.9 met­ric tons sequestered by sus­tain­ably man­aged almond orchards, 1.5 met­ric tons for vine­yards or 0.5 met­ric tons for corn.

“Olive trees’ exten­sive root sys­tems help main­tain soil organic car­bon lev­els, fur­ther pro­mot­ing long-term car­bon stor­age,” the authors of the review wrote.

According to Kyriakides, soil is at the heart of the One Health sys­tem.

“We have to think about soil health not just as agri­cul­ture but as envi­ron­ment, as pre­ven­tion. The olive tree con­tributes to soil sta­bil­ity, to water reten­tion, to pre­vent­ing ero­sion. That dimen­sion is crit­i­cal.”

He sug­gested that future research could explore how olive cul­ti­va­tion sup­ports resilience against cli­mate-dri­ven threats, includ­ing wild­fires and drought.

“We’re see­ing evi­dence that olive groves recover faster than any­thing else after wild­fires,” Kyriakides said. ​“And if you use groves as buffers, they can help pre­vent soil ero­sion and even slow the spread of fires. That’s another dimen­sion of One Health: the tree as a tool for pre­ven­tion and recov­ery.”

Kyriakides added that a panel focus­ing specifically on the role of olive trees in wild­fire pre­ven­tion and recov­ery might be included at the 7^th International Yale Symposium on Olive Oil and Health next December.

Regarding the impact of olive trees on human health, the evi­dence is long-stand­ing and grow­ing.

“We know that olive oil, olives, even teas from olive leaves are good for your health,” Kyriakides noted.

The review con­sid­ers a sub­stan­tial body of research that has exam­ined, among other things, the ben­e­fits of olive oil con­sump­tion on cho­les­terol lev­els, ath­er­o­scle­ro­sis, vas­cu­lar func­tion, and car­dio­vas­cu­lar health, as well as its effects on dia­betes and neu­rode­gen­er­a­tive dis­eases.

“We’ve known that since six decades ago, and we’re still advanc­ing new areas of research such as brain health, gut micro­biome, inflam­ma­tion and oxida­tive stress,” Kyriakides explained.

“It’s always twofold,” the researcher said, refer­ring to research on olive oils. ​“First, the mech­a­nis­tic level: how bioac­tive phe­nols affect inflam­ma­tion, oxi­da­tion and cell sig­nal­ing. And then the big pic­ture: large clin­i­cal stud­ies show­ing changes in LDL cho­les­terol, insulin resis­tance and blood pres­sure.”

Olive groves are also increas­ingly being man­aged as ecosys­tems that inte­grate live­stock and cul­ti­va­tion.

“I’ve seen it in Italy, Spain, Greece,” he said. ​“People are incor­po­rat­ing ani­mals, chick­ens, don­keys, sheep, into groves. It’s not addi­tive, it’s syn­er­gis­tic,” Kyriakides remarked.

“The ani­mals pro­vide manure, they eat weeds or pests, they ben­e­fit from leaves and trim­mings and in return they help the soil and the trees. It’s a liv­ing sys­tem.”

Olive cul­ti­va­tion can trans­form land­scapes, hav­ing a last­ing impact on bio­di­ver­sity and the local cli­mate.

“Think of what hap­pened in Lesbos in Greece,” Kyriakides said, refer­ring to the island in the Aegean Sea. There, an almost desert-like area was revi­tal­ized by the plant­ing of olive groves decades ago. ​“Temperature went down by three or four degrees Celsius, rain­fall increased, birds and ani­mals came back,” Kyriakides noted. ​“You drive to this place and think, how can they grow olive trees here? And yet the trees cre­ate a micro­cli­mate that sus­tains life.”

Kyriakides empha­sized the per­ma­nence of the olive tree.

“Once you plant it, it’s for hun­dreds of years,” he said. ​“It’s a one-time invest­ment that keeps giv­ing. Health, food, resilience, cul­ture. It ties gen­er­a­tions together.”

The review also focused on olive crop by-prod­ucts, which have tra­di­tion­ally been treated as waste but are becom­ing cru­cial ele­ments of a sus­tain­able cir­cu­lar econ­omy.

According to Kyriakides, olive oil mills typ­i­cally pro­duce olive oil as about 20 per­cent of total out­put, while the remain­ing 80 per­cent becomes a by-prod­uct.

“People are get­ting very cre­ative in approach­ing this. In Spain, I saw a pre­sen­ta­tion where they’re mak­ing car parts, fend­ers, out of olive by-prod­ucts,” Kyriakides said.

“Two years ago in Germany, they used it to make fur­ni­ture like step stools. In Italy, the University of Bari showed how a mill retro­fit­ted for energy was pro­duc­ing elec­tric­ity and heat for hun­dreds of homes,” he explained.

“For three months of the year those fam­i­lies didn’t have to pay for energy. Nothing should go to waste,” the researcher noted.

According to Kyriakides, the new review study is not just about olives but about a vision for agri­cul­ture and health.

“Everything ties together,” he said. ​“When you put the olive tree at the cen­ter, you see how human health, ani­mal health and the envi­ron­ment are all con­nected.”

“And even within each, there’s com­plex­ity, the mech­a­nisms at the cel­lu­lar level, the ecosys­tems at the land­scape level, the cul­tural tra­di­tions that sus­tain it. It’s fas­ci­nat­ing to think it all starts from this tree,” he added.

By fram­ing olive cul­ti­va­tion through the lens of One Health, the researchers invite pol­i­cy­mak­ers, pro­duc­ers and sci­en­tists to rethink what agri­cul­ture means in the 21^st cen­tury.

“It’s a very inter­est­ing set of rela­tion­ships,” Kyriakides said. ​“And it shows that sus­tain­abil­ity isn’t an abstract con­cept. It is some­thing alive, rooted and grow­ing.”