Olive Oil

Research summary

• Olive oil is one of the most extensively studied single foods in longevity research, both through its central role in Mediterranean-diet trials and in large cohort studies of the oil itself.
• The largest single-food analysis, following 60,582 women in the Nurses' Health Study and 31,801 men in the Health Professionals Follow-up Study for up to 28 years, found the highest olive oil consumers (>0.5 tablespoon/day) had 19% lower all-cause mortality than those who rarely consumed it, alongside 19% lower cardiovascular mortality, 17% lower cancer mortality and 29% lower neurodegenerative-disease mortality; replacing 10g/day of margarine, butter, mayonnaise or dairy fat with olive oil was linked to 8-34% lower mortality across these causes.
• Two independent meta-analyses corroborate the dose-response relationship at much larger scale: a 2022 pooled analysis of over 800,000 participants found each additional 25g/day of olive oil was associated with an 11% lower risk of all-cause mortality, and a 2024 meta-analysis spanning 2.7 million participants found an 8% lower risk of all-cause mortality per 10g/day increment, with a separate 2022 dose-response analysis finding little additional benefit beyond roughly 20g/day of intake.
• This isn't purely observational: the landmark PREDIMED randomized trial assigned over 7,400 people at high cardiovascular risk to a Mediterranean diet supplemented with extra-virgin olive oil, a version supplemented with mixed nuts, or a low-fat control diet, and found the olive-oil group had a 30% lower rate of major cardiovascular events after a median 4.8 years of follow-up.
• The main caveat is that outside of PREDIMED, essentially all of this evidence comes from large observational cohorts that cannot fully separate olive oil's own effect from the broader dietary pattern — more vegetables, less processed food — that tends to accompany it, and no meta-analysis has found a protective association between olive oil intake and cancer incidence specifically, only cancer mortality in the largest single cohort.