An analysis suggests that a higher olive oil intake is inversely associated with the risk of cardiovascular and all-cause mortality
An olive oil intake of around 20g/day has been shown to be associated with a reduced risk of both cardiovascular and all-cause mortality according to the results of a meta-analysis of prospective studies by Greek and Chinese researchers.
Olive oil contains a number of plant polyphenols that have health benefits including anti-mutagenic, anti-inflammatory, anti-thrombotic, anti-atherogenic, and anti-allergic effects. In addition, the monounsaturated fatty acids present in olive oil and in particular, oleic acid, might have positive impacts on lipid peroxidation. In fact, a 2019 network meta-analysis examining the role of olive oil in the modification of metabolic factors such as glucose and circulating lipids, found that olive oil polyphenols increased HDL-cholesterol and that overall, the beneficial effect of olive oil were more pronounced in subjects with an established metabolic syndrome or other chronic conditions/diseases. Furthermore, while some analyses indicate that a higher olive oil intake is associated with lower risk of coronary heart disease, other studies that have examined the link between dietary fat intake (including olive oil) and cardiovascular disease (CVD) events, have found no association.
Trying to provide more definitive evidence, in the present study, researchers performed a meta-analysis of prospective cohort studies to investigate the relationship between olive oil consumption and risk of CVD and all-cause mortality. The team included studies in which the exposure of interest was olive oil consumption and where the recorded outcomes were total CVD or all-cause mortality.
Olive oil intake and cardiovascular and all-cause mortality outcomes
A total of 13 prospective cohort studies were included and the duration of follow-up ranged from 4 to 28 years. Most of the studies collected the dietary data on olive oil intake from food-frequency questionnaires.
In an assessment of CVD risk, the pooled relative risk (RR) for the highest versus the lowest olive oil intake was 0.85 (95% CI 0.77 – 0.93, p < 0.001). In subgroup analysis, this relationship was independent of the region of study, sample size, follow-up duration, sex, or even the type of olive oil.
In terms of all-cause mortality and again comparing the highest and the lowest levels of intake, there was a significant reduction in all-cause mortality (RR: 0.83, 95% CI 0.77 –0.90, p < 0.001). As with CVD risk, there was no significant impact of any of the examined factors in subgroup analysis.
When the researchers looked at the amount of olive oil consumed, the relative risk for CVD for each 5g/day increment was 0.96 (95% CI 0.93 – 0.99, p = 0.005) and this was a similar order of magnitude for all-cause mortality. Interestingly, the reduction in CVD risk was largely attenuated with an intake above 20 g/day and there were also no preventive mortality effects when intake exceeded 20 g/day.
The authors concluded that consuming up to 20g/day of olive oil was associated with a reduced CVD and all-cause mortality risk but that there were no apparent benefits from exceeding this amount.
Citation
Xia M et al. Olive oil consumption and risk of cardiovascular disease and all-cause mortality: A meta-analysis of prospective cohort studies. Front Nutr 2022
