Health Benefits of High-Phenolic Olive Oils Decoded through Gene Expressions

EVOO containing high levels of polyphenols improves insulin sensitivity and modulates different pathways in inflammatory cells of healthy subjects.

Aug. 19, 2016
By Negar Jamshidi

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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.

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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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