The Mediterranean diet (MeD) is well-known to impart con­sid­er­able pro­tec­tion against the occur­rence of car­dio­vas­cu­lar dis­ease and can­cer. In par­tic­u­lar, the plethora of pro­tec­tive health ben­e­fits of the MeD includ­ing improved lipid pro­file and reduced inflam­ma­tion has been linked largely to the high lev­els of fatty acid con­tent found in extra vir­gin olive oil (EVOO).

However, there is still no clar­ity as to which com­po­nents of EVOO are respon­si­ble for the reg­u­la­tion of genes involved in inflam­ma­tory, anti-oxi­dant or immune path­ways.
See more: Olive Oil Health Benefits
In addi­tion, while there are a few human clin­i­cal stud­ies on the acute effect of high intake of EVOO on gene expres­sion changes, to date there are no reports on the EVOO effect on the whole tran­scrip­tome expres­sion pro­file (genome and RNA).

The reg­u­la­tion of nor­mal bio­log­i­cal func­tion at the cel­lu­lar and mol­e­c­u­lar lev­els is through small RNA sequences known as MicroRNA (miRNA) that have been promis­ing as ther­a­peu­tic tar­gets for cer­tain dis­eases. Advances in whole genome mRNA (tran­scrip­tome) sequenc­ing has led to com­pre­hen­sive analy­sis of RNA tran­scripts in a given tis­sue sam­ple.

In a recent study pub­lished in Biochim Biophys Acta, a col­lab­o­ra­tive group of researchers in Italy took advan­tage of tran­scrip­tome sequenc­ing tech­nol­ogy and inves­ti­gated the health pro­tec­tive mech­a­nisms of extra vir­gin olive oil by iden­ti­fy­ing gene expres­sion sig­na­ture after an acute con­sump­tion of EVOO in both healthy vol­un­teers and meta­bolic syn­drome patients.

The study involved con­sump­tion of a sin­gle dose of low- or high-polyphe­nol extra vir­gin olive oil (50ml) by healthy vol­un­teers and patients with meta­bolic syn­drome on dif­fer­ent occa­sions. The selected EVOOs were sim­i­lar in fatty acid but dif­fered in polyphe­nol com­po­si­tions.

The sci­en­tists found that acute polyphe­nol-rich EVOO effects in healthy par­tic­i­pants led to marked improve­ment in insulin sen­si­tiv­ity and glu­cose metab­o­lism, at the same time sup­port­ing miRNA and gene expres­sion in inflam­ma­tion and immune responses.

On the con­trary, these bio­chem­i­cal and mol­e­c­u­lar effects of EVOO were largely absent in patients affected by meta­bolic syn­drome or par­tic­i­pants who con­sumed low-polyphe­nol EVOO sug­ges­tive of a puta­tive role for the phe­no­lic com­po­nent.

Next, the researchers sought to deter­mine whether such ben­e­fits of EVOO in healthy vol­un­teers were attrib­uted to the polyphe­nols or the fatty acid com­po­nents of EVOO.

They found that in vol­un­teers who con­sumed polyphe­nol-rich EVOO, there was a sig­nif­i­cant change in the expres­sion of genes pre­vi­ously know to be acti­vated by fatty acids than any other EVOO com­po­nents. In con­trast, the major­ity of gene expres­sions remained the same in indi­vid­u­als after inges­tion of extra vir­gin olive oil low in polyphe­nols.

The sci­en­tists fur­ther demon­strated that the effects of EVOO high in polyphe­nols at the mol­e­c­u­lar level sup­ported reg­u­la­tion of miRNA exert­ing var­i­ous effects on inflam­ma­tion, can­cer and insulin resis­tance.

The key mes­sage of this study was that “the intake of EVOO con­tain­ing high phe­nols improves insulin sen­si­tiv­ity and mod­u­lates dif­fer­ent path­ways in inflam­ma­tory cells of healthy sub­jects; most of these changes point to a ben­e­fi­cial role of EVOO in pro­mot­ing health toward its anti-inflam­ma­tory, anti-can­cer, and antiox­i­dant prop­er­ties.”


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