Replacing Saturated Fats With Olive Oil Saves Lives, Harvard Research Suggests

The results of the first long-term inves­ti­ga­tion into the impact of olive oil con­sump­tion in the United States demon­strate that most Americans could greatly ben­e­fit from replac­ing the sat­u­rated fats in their diets with olive oil and extra vir­gin olive oil.

Common causes of ill­ness or death, such as car­dio­vas­cu­lar and res­pi­ra­tory dis­eases, dia­betes, can­cer and neu­rode­gen­er­a­tive dis­or­ders con­nected to brain aging, are cur­tailed up to 20 or 30 per­cent by the long-term use of healthy unsat­u­rated olive oil.

The lat­est research pub­lished in the Journal of the American College of Cardiology by a team of sci­en­tists from the Harvard T.H. Chan School of Public Health’s nutri­tion depart­ment inves­ti­gated the impact of olive oil on a large sam­ple of the American pub­lic for the first time.

“In two large cohort stud­ies with up to 30 years of fol­low-up, peo­ple who ate higher amounts of olive oil showed a lower risk of all-cause and cause-spe­cific mor­tal­ity com­pared to peo­ple who never or almost never eat olive oil,” Marta Guasch-Ferre, a senior research sci­en­tist at the Harvard T.H. Chan School of Public Health and co-author of the study, told Olive Oil Times.

The sci­en­tists used mul­ti­vari­able-adjusted mod­els to exam­ine the results of the Nurses’ Health Study and the Health Professionals Follow-up Study con­ducted between 1990 and 2018, which involved more than 60,000 women and more than 31,000 men.

All sub­jects were free of car­dio­vas­cu­lar dis­ease and can­cer at the begin­ning of the study. Their diets were assessed every four years.

The researchers found that those who con­sumed olive oil more often would have a 19-per­cent lower risk of dying from car­dio­vas­cu­lar dis­ease, 17 per­cent from can­cer and 18 per­cent from res­pi­ra­tory dis­ease.

They also found that deaths occur­ring due to neu­rode­gen­er­a­tive dis­eases fell by 29 per­cent.

The research high­lights how even a par­tial sub­sti­tu­tion of daily sat­u­rated fat con­sump­tion with olive oil can still carry sig­nif­i­cant ben­e­fits.

“Replacing 10 grams of mar­garine, but­ter, may­on­naise or dairy fat with the same amount of olive oil was asso­ci­ated with eight to 34 per­cent lower risk of total and cause-spe­cific mor­tal­ity,” Guasch-Ferre said.

According to the researchers, there is a grow­ing body of lit­er­a­ture about the ben­e­fits of reduc­ing ani­mal fat and sat­u­rated fat intake in favor of veg­etable oils.

“The main mes­sage is that our results pro­vide fur­ther sup­port for rec­om­men­da­tions to replace sat­u­rated fat and ani­mal fat with unsat­u­rated plant oils, such as olive oil, for the pre­ven­tion of pre­ma­ture death,” Guasch-Ferre said.

Olive oil cul­ture and olive oil’s health ben­e­fits are not yet wide­spread in American cul­ture, while fats such as but­ter and mar­garine are a well-estab­lished part of most peo­ple’s diet.

Researchers hope that their find­ings will also help both patients and the gen­eral pub­lic bet­ter under­stand the sig­nif­i­cant impact of health­ier fats and how to imple­ment them into their diets.

“Indeed, the con­sump­tion of olive oil was lower than other stud­ies I have con­ducted pre­vi­ously in Mediterranean pop­u­la­tions,” Guasch-Ferre said. ​“Also, another lim­i­ta­tion was that we could not dif­fer­en­ti­ate among grades of olive oil.”

“It is known that extra-vir­gin and vir­gin are a good source of healthy fats, but they also con­tain high amounts of other bioac­tive com­pounds such as polyphe­nols and antiox­i­dants that have shown anti-inflam­ma­tory and antiox­i­dant prop­er­ties,” she added.

“In our study, we showed that in sta­tis­ti­cal mod­els when olive oil was replac­ing but­ter, may­on­naise, mar­garine and other ani­mal fats, it was asso­ci­ated with lower risk of total mor­tal­ity and mor­tal­ity from causes such as can­cer, car­dio­vas­cu­lar dis­ease or neu­rode­gen­er­a­tive dis­eases,” Guasch-Ferre con­tin­ued.

Previous stud­ies have shown how spe­cific olive oil con­tents may affect can­cer pro­gres­sion and serve as treat­ment ther­a­pies.

For exam­ple, the National Cancer Institute is research­ing oleo­can­thal, a polyphe­nol, for its poten­tial to help pre­vent breast can­cer. Researchers from the University of Louisiana-Monroe are also inves­ti­gat­ing the use of oleo­can­thal in treat­ing the dead­liest type of breast can­cer.

Other research has demon­strated how olive oil con­sump­tion could pos­i­tively impact neu­rode­gen­er­a­tive dis­eases, such as Alzheimer’s dis­ease, by pre­vent­ing the buildup of plaque in the brain.

Olive oil-spe­cific prop­er­ties were taken into account by Harvard researchers while inves­ti­gat­ing their asso­ci­a­tion with reduced mor­tal­ity among olive oil con­sumers.

“Several mech­a­nisms could account for the asso­ci­a­tions,” Guasch-Ferre said. ​“Olive oil is high in oleic acid and is less sus­cep­ti­ble to oxi­da­tion than more unsat­u­rated fatty acids. It has also been observed that olive oil can have favor­able effects on endothe­lial dys­func­tion, hyper­ten­sion, inflam­ma­tion, insulin sen­si­tiv­ity and dia­betes.”

“We exam­ined the impact as a whole, and also impor­tantly, the hypo­thet­i­cal effects of reduc­ing other fats by increas­ing olive oil intake,” she added.

In an accom­pa­ny­ing edi­to­r­ial on the Journal, Susanna Larsson of Uppsala University in Sweden noted how more research is needed to fully under­stand olive oil’s impact on health.

“To sum­ma­rize, the cur­rent study and pre­vi­ous stud­ies have found that con­sump­tion of olive oil may have health ben­e­fits,” she wrote. ​“However, sev­eral ques­tions remain. Are the asso­ci­a­tions causal or spu­ri­ous? Is olive oil con­sump­tion pro­tec­tive for cer­tain car­dio­vas­cu­lar dis­eases (e.g., stroke and atrial fib­ril­la­tion) only or also for other major dis­eases and causes of death? What is the amount of olive oil required for a pro­tec­tive effect?”

“More research is needed to address these ques­tions,” she con­cluded.

• Journal of the American College of Cardiology
• Journal of the American College of Cardiology