Greater olive oil consumption associated with lower total mortality risk


Higher olive oil intake is associated with a lower risk for total and cause-specific mortality, according to a study published in the Journal of the American College of Cardiology.

This finding is based on analysis of data from the ongoing Nurses’ Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). A total of 60,582 women and 31,801 men without a history of cardiovascular disease (CVD) or cancer at baseline were included.

Dietary intake of over 130 items was assessed via a validated semiquantitative food frequency questionnaire (FFQ) administered every 4 years. The baseline year used for analysis of both studies was 1990, when olive oil consumption was first included in the FFQs.

Participants’ mean olive oil consumption increased from 1.6 g/d in 1990 to approximately 4 g/d in 2010. Margarine consumption decreased from approximately 12 g/d in 1990 to approximately 4 g/d in 2010. Consumption of other fats was stable. After 28 years of follow-up, 36,856 deaths were recorded (22,768 in the NHS and 14,076 in the HPFS).

After adjustment for demographic and lifestyle factors, the pooled multivariable-adjusted hazard ratios (HR) for participants in the highest category of olive oil consumption (>0.5 tbsp/day or >7 g/d), compared with those in the lowest category (never or <1 per month), were 0.81 for total mortality (95% CI, 0.78-0.84), 0.81 for cardiovascular mortality (95% CI, 0.75-0.87), 0.83 for cancer mortality (95% CI, 0.78-0.89), 0.71 for neurodegenerative mortality (95% CI, 0.64-0.78), and 0.82 for respiratory mortality (95% CI, 0.72-0.93). For each additional 5-gram increase in olive oil intake as a continuous variable, significant inverse associations for total mortality and cause-specific mortality were found.

Sensitivity analyses that adjusted for additional socioeconomic factors did not substantially change the results. Pooled HR for total mortality for high vs low olive oil intake was 0.81 (95% CI, 0.78-0.84).

Individuals of Southern European and/or Mediterranean ancestry had greater olive oil consumption and a 6% (HR, 0.94; 95% CI, 0.92-0.96) lower risk of total mortality, compared with the 4% risk reduction in the non-Mediterranean ancestry subgroups (per each 5-gram increase in olive oil intake).

The researchers estimated that substituting 10 g/d of margarine with 10 g/d of olive oil was associated with a 13% lower risk of total mortality (HR, 0.87; 95% CI, 0.85-0.89). The corresponding HR estimate with butter was 0.86 (95% CI, 0.83-0.88), 0.81 for mayonnaise (95% CI, 0.78-0.84), and 0.87 for dairy fat (95% CI, 0.84-0.89).

The researchers noted several limitations to their findings, including the potential for residual confounding and the fact that participants were predominantly non-Hispanic White health professionals. The investigators also used validated self-reported FFQs and could not distinguish among different types of olive oil with varying amounts of polyphenols and other nonlipid bioactive compounds.

“Our results support current dietary recommendations to increase the intake of olive oil and other unsaturated vegetable oils in place of other fats to improve overall health and longevity,” the study authors stated.

In an accompanying editorial, Susanna C. Larsson, PhD, acknowledged the health benefits of olive oil consumption, based on the current and previous studies.

“However, several questions remain,” Dr Larsson wrote. “Are the associations causal or spurious? Is olive oil consumption protective for certain CVDs (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.”, 19 January 2022