Compared with men and women who rarely or never consumed olive oil (the lowest intake), those who consumed greater than 0.5 tablespoon/day or more than 7 g/day (the highest intake) had a 19% lower mortality risk over a 28-year follow-up, starting from an average age of 56 years.
Moreover, compared with those with the lowest olive oil intake, those with the highest intake had a 19% lower cardiovascular disease (CVD) mortality, a 17% lower risk of dying from cancer, a 29% lower risk of dying from neurodegenerative disease, and an 18% lower risk of dying from respiratory disease during follow-up.
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The researchers estimate that replacing 10 g/day of margarine, butter, mayonnaise, or dairy fat with the same amount of olive oil is associated with an 8%-34% lower risk of death from various causes.
The study by Marta Guasch-Ferré, PhD, and colleagues was published online Jan. 10 in the Journal of the American College of Cardiology.
Results support plant-based dietary fat recommendations
“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 researchers summarize.
However, “I wouldn’t say that olive oil is the only way to help you live longer,” Dr. Guasch-Ferré, a senior research scientist in the department of nutrition, Harvard T.H. Chan School of Public Health, Boston, cautioned in an interview with this news organization.
“Other things are very important, such as not smoking, doing physical activity, etc., but one recommendation could be to try to eat more plant-based food including olive oil and healthy fat,” she added, and to use it for cooking, salad dressing, and baking, and substitute it for saturated fat or animal fat, especially for cooking.
The study suggests that people should “consume a more plant-based diet and prioritize fatty acids such as olive oil because they have a better nutritional composition (high in phenols and antioxidants), instead of using butter or margarines or other animal fats that have been shown to have detrimental effects for health,” she added, which is consistent with recommendations in the Dietary Guidelines for Americans.
“That said,” Dr. Guasch-Ferré summarized, “replication is needed in other cohorts and populations to see if the results are similar.”
In an accompanying editorial, Susanna C. Larsson, PhD, writes that “this was a well-designed study, with long-term follow-up and repeated measurements of dietary intake and other risk factors for diseases.”
“However, the difference in olive oil consumption between those with the highest and those with the lowest/no olive oil consumption was very low (0.5 tablespoon) and a [12%] reduced mortality risk was observed already at a much lower intake (0.5 teaspoon, about 1.5 g/day) of olive oil,” she noted in an email to this news organization.
“It’s a bit hard to believe that such a small amount could have an independent effect on mortality risk,” Dr. Larsson, associate professor of epidemiology at the Karolinska Institutet, Stockholm, cautioned.
Like Dr. Guasch-Ferré, she noted that “just adding one or two teaspoons of olive oil to the diet each day will likely not change the risk of mortality.”
Rather, “people may need to make larger changes in the whole diet, not focus on fat only. An overall healthier diet, rich in nonrefined plant-based foods (vegetables, whole grains, nuts), low/no intake of processed foods, and a switch to healthier fat (eg, olive oil) is needed.”
Importantly, “this study cannot say anything about causality, that is, whether it’s olive oil specifically that reduces mortality risk or if there are many other beneficial factors that act together to reduce mortality rate among those with high olive oil consumption.”
The researchers acknowledge this observational study limitation and that the findings may not be generalizable to other populations.