Olive oil consumption may cut risk for CV, all-cause death
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A diet that includes approximately half a tablespoon of olive oil daily may cut risk for CV death and all-cause death by 19%, according to research published in the Journal of the American College of Cardiology.
In an analysis of two large U.S. cohorts, researchers also found that replacement of margarine, butter, mayonnaise and dairy fat with olive oil was similarly associated with lower risk for total and cause-specific mortality.
“Clinicians should be counseling patients to replace certain fats, such as margarine and butter, with olive oil to improve their health,” Marta Guasch-Ferré, PhD, a senior research scientist and instructor in medicine at the Harvard T.H. Chan School of Public Health, told Healio. “Our study helps clinicians make specific recommendations that will be easy for patients to understand and hopefully implement into their diets.”
Assessing olive oil intake
Guasch-Ferré and colleagues analyzed olive oil intake from two prospective cohorts of healthy U.S. adults: the Nurses’ Health Study (1990-2018; n = 60,582 women) and the Health Professionals Follow-up Study (1990-2018; n = 31,801 men). Participants completed a semiquantitative food frequency questionnaire every 4 years. Olive oil consumption was categorized by frequency: never or less than once per month (reference); up to 4.5 g per day (< 1 teaspoon); 4.5 g to 7 g per day (1 teaspoon to 0.5 tablespoons); and at least 7 g per day ( 0.5 tablespoons). Researchers used Cox proportional-hazards models to estimate HRs for total and cause-specific mortality.
Across both cohorts, 36,856 participants died during 28 years of follow-up. Mean olive oil consumption increased from 1.6 g per day in 1990 to about 4 g per day in 2010; margarine consumption fell from a mean of 12 g per day in 1990 to 4 g per day in 2010.
Compared with participants who rarely or never consumed olive oil, the adjusted pooled HR for all-cause mortality among participants reporting the highest consumption of olive oil was 0.81 (95% CI, 0.78-0.84), with results persisting after adjustments for demographic and lifestyle factors.
Higher olive oil intake was associated with 19% lower risk for CVD mortality (HR = 0.81; 95% CI, 0.75-0.87), a 17% lower risk for cancer mortality (HR = 0.83; 95% CI, 0.78-0.89), a 29% lower risk for neurodegenerative disease mortality (HR = 0.71; 95% CI, 0.64-0.78) and an 18% lower risk for respiratory disease mortality (HR = 0.82; 95% CI, 0.72-0.93).
In substitution analyses, replacing 10 g per day of margarine, butter, mayonnaise and dairy fat with the equivalent amount of olive oil was associated with 8% to 34% lower risk for total and cause-specific mortality.
Researchers observed no associations when olive oil was compared with other vegetable oils combined. Guasch-Ferré said researchers were not able to assess the effect of different olive oil varieties on mortality risk.
“It is known that extra-virgin and virgin olive oil varieties have higher amounts of polyphenols that have been associated with better lipid profiles and less inflammation,” Guasch-Ferré told Healio. “It would be interesting to assess the differences among types of olive oil and the health effects of other vegetable oils on health outcomes as well as disentangle the mechanisms of this associations such as identifying metabolomic markers of olive oil intake. Further research is needed to investigate the mechanisms underlying the associations between olive oil consumption and health and which population groups are most likely to benefit.”
Benefit by olive oil type
In a related editorial, Susanna C. Larsson, PhD, senior researcher and associate professor of cardiovascular and nutritional epidemiology at Karolinska Institutet in Stockholm, wrote that the inability to distinguish between olive oil varieties is important, as refined olive oil has lower levels of phenolic compounds compared with extra-virgin olive oil “and may therefore have fewer health benefits.”
“Several questions remain,” Larsson wrote. “Are the associations causal or spurious? Is olive oil consumption protective for certain CVDs only or also for other major diseases and causes of death? What is the amount of olive oil required for a protective effect? Is the potential effect ... confined to polyphenol-rich extra-virgin olive oil or are refined olive oil and other vegetable oils as beneficial? More research is needed to address these questions.”
Previous observational studies have shown a beneficial CV effect when diets are enriched with olive oil. As Healio previously reported, in an analysis of the PREDIMED trial, a traditional Mediterranean diet enriched with virgin olive oil enhanced the function of HDL compared with a Mediterranean diet enriched with nuts or a low-fat control diet. However, Larsson noted that olive oil consumption in the PREDIMED trial “differed remarkably” from U.S. consumption.
Reference:
For more information:
Marta Guasch-Ferré, PhD, can be reached at mgausch@hsph.harvard.edu; Twitter: @martaguasch1.
Perspective
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Jamy D. Ard, MD
This study lends support to and confirms the general guidance that plant-based sources of fat are better for you relative to animal-based sources. What is unique about this analysis is it focuses on a U.S.-based population, where the background olive oil intake is relatively low. It is remarkable to see this association with reductions in disease risk and mortality with a small amount of olive oil intake. The highest intake seen here, greater than 7 g per day, is the equivalent of about 0.5 tablespoons. The amount used for the substitution model was 10 g, so again, less than 1 tablespoon. Replacing a small amount of saturated fat with olive oil looks like a reasonable thing to do, with potentially a lot of benefit.
Regarding olive oil type — refined vs. extra virgin — the jury is still out regarding whether one provides more benefit vs. the other, at least based on these findings. The type of dietary assessment used here does not provide that answer. A lot of the conclusions about the role of refined vs. extra virgin come from the PREDIMED study, where researchers did deploy extra virgin olive oil.
One of the takeaways is we do need a randomized controlled trial in this setting with a more diverse population. These analyses that include health professionals are largely made up of professional white participants, limiting generalizability.
If you can shift the population-wide intake toward that 10-g daily direction, the impact could be significant. From a food production standpoint, we are not talking about a huge change in development of food products. This could be small changes that lead to large differences.
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