Olive oil consumption may cut dementia mortality risk by nearly 30%, research shows

A recent study published in JAMA Network Open reveals that consuming more than a teaspoon of olive oil daily could significantly reduce the risk of dying from dementia, and that replacement of margarine or mayonnaise with olive oil could also reduce this risk.

The Mediterranean diet has been celebrated for its cardiovascular benefits. Recently, researchers have turned their attention to its potential to protect cognitive health. Olive oil, a staple of the Mediterranean diet, is rich in healthy fats and antioxidants, which are thought to offer anti-inflammatory and neuroprotective effects.

The study aimed to explore the relationship between olive oil consumption and the risk of dementia-related death. Researchers also sought to understand how olive oil intake interacts with overall diet quality and the replacement of other dietary fats with olive oil.

The investigation was a prospective cohort study, which is a study that follows a group of participants over time. The research team proposed studying a US population could offer new insights, as most research on the Mediterranean diet is conducted in Mediterranean countries.

Consequently the team, led by Anne-Julie Tessier from Harvard University, analyzed data from 93,383 US adults (60,582 women and 31,801 men) who were free from cardiovascular disease and cancer at the start of the study, for 28 years.

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Participants’ olive oil intake was measured every four years through detailed food frequency questionnaires. Consumption was categorized into “never or less than once per month”, “greater than 0 to less than or equal to 4.5 grams per day”, “greater than 4.5 grams per day to less than or equal to 7 grams per day”, and “greater than 7 grams per day”.

Death from dementia was obtained from death records, and confirmed by physician review.

Following data analysis, it was discovered that individuals who consumed at least 7 grams of olive oil per day – which is a little more than half a tablespoon – had a 28% lower risk of dementia-related death compared to those who rarely or never consumed it. This finding was not affected by diet quality.

Tessier and colleagues proposed a potential mechanism behind this, “olive oil consumption may lower dementia mortality by improving vascular health. Several clinical trials support the effect of olive oil in reducing [cardiovascular disease] via improved function [of the membrane that lines the inside of the heart and blood vessels], [blood clotting], lipid metabolism, oxidative stress … and decreased inflammation.”

Moreover, replacing just 5 grams per day of margarine or mayonnaise with olive oil was associated with an 8% to 14% lower risk of dementia mortality, respectively.

“At the time of the study, margarine and mayonnaise contained considerable levels of hydrogenated trans-fats. The latter were strongly associated with all-cause mortality, [cardiovascular disease], type 2 diabetes, and dementia, which may explain the lower dementia-related death risk observed when replacing it with olive oil,” the authors explained.

While the study’s findings are compelling, there are some limitations. For instance, the study did not differentiate among various types of olive oil that differ in their compound content.

The study, “Consumption of Olive Oil and Diet Quality and Risk of Dementia-Related Death”, was authored by Anne-Julie Tessier, Marianna Cortese; Changzheng Yuan, Kjetil Bjornevik, Alberto Ascherio, Daniel D. Wang, Jorge E. Chavarro, Meir J. Stampfer, Frank B. Hu, Walter C. Willett and Marta Guasch-Ferré.