Study Finds Virgin Olive Oil Linked to Better Gut Health and Slower Cognitive Decline

Summary

Higher grades of olive oil, such as vir­gin and extra vir­gin, are asso­ci­ated with bet­ter cog­ni­tive func­tion and gut micro­biota com­pared to refined olive oils, accord­ing to a study on adults aged 55 to 75. The research, part of the PREDIMED-Plus study, found that the gut micro­biota par­tially medi­ated the rela­tion­ship between vir­gin olive oil intake and cog­ni­tive preser­va­tion over two years, high­light­ing the impor­tance of olive oil qual­ity in pro­mot­ing brain health.

New research sug­gests that only higher grades of olive oil, such as vir­gin or extra vir­gin olive oil, deliver sig­nif­i­cant health ben­e­fits.

According to research pub­lished in Springer Nature Link, higher con­sump­tion of vir­gin olive oil is asso­ci­ated with bet­ter preser­va­tion of cog­ni­tive func­tion and a more favor­able gut micro­biota pro­file. Higher intake of refined olive oils, by con­trast, was linked to lower micro­bial diver­sity and faster cog­ni­tive decline.

The study fol­lowed 656 adults aged 55 to 75 with over­weight or obe­sity and meta­bolic syn­drome. All par­tic­i­pants were cog­ni­tively healthy at base­line and were mon­i­tored for two years as part of the PREDIMED-Plus study, a large Spanish cohort that builds on ear­lier PREDIMED research on the Mediterranean diet.

The research was a prospec­tive obser­va­tional analy­sis and did not assign par­tic­i­pants to spe­cific olive oil inter­ven­tions. Instead, it exam­ined nat­u­rally occur­ring dietary pat­terns over time.

At base­line, par­tic­i­pants com­pleted a val­i­dated food fre­quency ques­tion­naire to assess total olive oil intake. This allowed researchers to dis­tin­guish between vir­gin and extra vir­gin olive oil con­sump­tion and refined or com­mon olive oil intake.

Stool sam­ples were col­lected to ana­lyze the gut micro­biota, the com­mu­nity of microor­gan­isms liv­ing in the diges­tive tract. Researchers sequenced the 16S ribo­so­mal RNA gene to iden­tify and com­pare bac­te­r­ial groups across par­tic­i­pants.

Cognitive func­tion was eval­u­ated at base­line and again after two years using a com­pre­hen­sive neu­ropsy­cho­log­i­cal test bat­tery cov­er­ing global cog­ni­tion, exec­u­tive func­tion, atten­tion and lan­guage.

“We wanted to inves­ti­gate how olive oil, a key food in the Mediterranean diet, influ­ences brain health and whether the gut micro­biota medi­ates this rela­tion­ship, as well as to dif­fer­en­ti­ate the impact of vir­gin olive oil com­pared with refined oils,” Jordi Salas-Salvadó and Jiaqi Ni told Olive Oil Times.

Salas-Salvadó is a pro­fes­sor of nutri­tion at Rovira i Virgili University in Spain and the study’s senior author. Ni is the first author and a researcher in the university’s Department of Biochemistry and Biotechnology.

“This ques­tion is par­tic­u­larly impor­tant in the con­text of an aging pop­u­la­tion and the increas­ing preva­lence of demen­tia, where pre­ven­tion through healthy dietary habits rep­re­sents one of the most promis­ing strate­gies to pro­tect long-term cog­ni­tive func­tion,” they said.

According to the researchers, most pre­vi­ous stud­ies exam­ined diet, micro­biota or cog­ni­tion sep­a­rately. ​“This work inte­grates these three ele­ments for the first time in a prospec­tive human study, help­ing to clar­ify that diet affects brain func­tion in part through gut bac­te­ria,” they noted.

A key focus of the study was the role of the gut micro­biota as an inter­me­di­ary between olive oil intake and brain health.

“The gut micro­biota is strongly influ­enced by diet,” the researchers said. ​“These bac­te­ria pro­duce com­pounds that can affect inflam­ma­tion, metab­o­lism and com­mu­ni­ca­tion with the brain, mak­ing the micro­biota a cen­tral com­po­nent of the so-called gut-brain axis.”

Beyond iden­ti­fy­ing asso­ci­a­tions, the team con­ducted medi­a­tion analy­ses to explore poten­tial mech­a­nisms. These analy­ses tested whether changes in the gut micro­biota partly explained the rela­tion­ship between olive oil con­sump­tion and cog­ni­tive changes.

After adjust­ing for con­found­ing fac­tors such as age, sex, edu­ca­tion, phys­i­cal activ­ity, energy intake and over­all diet qual­ity, results showed that the gut micro­biota par­tially medi­ated the asso­ci­a­tion between higher intake of vir­gin olive oils and bet­ter cog­ni­tive preser­va­tion over two years.

Gut micro­biota diver­sity was assessed using alpha and beta diver­sity met­rics. Alpha diver­sity reflects ecosys­tem robust­ness, while beta diver­sity indi­cates dif­fer­ences in micro­bial com­po­si­tion between indi­vid­u­als.

Higher intake of vir­gin olive oil was asso­ci­ated with greater alpha diver­sity, a marker of a more resilient gut ecosys­tem. In con­trast, higher con­sump­tion of refined olive oil was asso­ci­ated with reduced micro­bial diver­sity.

Beta diver­sity analy­ses revealed dis­tinct micro­bial com­mu­nity struc­tures asso­ci­ated with dif­fer­ent olive oil types, sug­gest­ing that olive oil qual­ity influ­ences not only the num­ber of bac­te­r­ial species present but also which species dom­i­nate.

The medi­a­tion effect was not observed for refined olive oils, rein­forc­ing the con­clu­sion that olive oil qual­ity plays a cen­tral role in bio­log­i­cally mean­ing­ful path­ways link­ing diet and cog­ni­tion.

One spe­cific micro­bial sig­nal emerged as sta­tis­ti­cally sig­nif­i­cant: the genus Adlercreutzia. Higher vir­gin olive oil intake was asso­ci­ated with a greater abun­dance of this genus, which, in turn, was linked to bet­ter cog­ni­tive per­for­mance.

Adlercreutzia is known for its role in metab­o­liz­ing polyphe­nols and other plant-derived com­pounds, sug­gest­ing a plau­si­ble bio­log­i­cal path­way con­nect­ing olive oil phe­no­lics, gut metab­o­lism and brain health.

“Not all olive oils are nutri­tion­ally the same,” Salas-Salvadó and Ni said. ​“Virgin or extra vir­gin olive oil retains more bioac­tive com­pounds, such as polyphe­nols, which may exert greater ben­e­fits on both the gut micro­biota and brain health com­pared with refined olive oils.”

They cau­tioned that treat­ing all olive oils as inter­change­able ​“can obscure impor­tant dif­fer­ences with rel­e­vant pub­lic health impli­ca­tions.”

The authors also noted the study’s lim­i­ta­tions. ​“Our research was con­ducted in older adults with over­weight or obe­sity and meta­bolic syn­drome, within a Mediterranean dietary pat­tern,” they said, adding that results should be extrap­o­lated cau­tiously to other pop­u­la­tions.

The researchers empha­sized that the study can­not estab­lish direct causal­ity and warned against inter­pret­ing the find­ings as uni­ver­sal dietary pre­scrip­tions.

Future research should include ran­dom­ized clin­i­cal tri­als, longer fol­low-up peri­ods and more detailed micro­biota analy­ses, they said.

“It will also be essen­tial to study other pop­u­la­tions and dietary con­texts,” Salas-Salvadó and Ni con­cluded, ​“par­tic­u­larly indi­vid­u­als at risk of cog­ni­tive decline who do not yet show symp­toms, where pre­ven­tion strate­gies could have the great­est impact.”