Olive oil is a major component of the Mediterranean diet, often used in salad dressings or as cooking oil. It is available in a variety of commercial grades and its contents (e.g., monounsaturated fats and phenolic compounds) vary depending on the olive variety, the picking season and growing environment, and other factors. Evidence suggests olive oil is safe and might confer slight cognitive benefits as part of a healthy diet.
Although olive oil is a component of other healthy interventions (such as the Mediterranean diet), few studies have examined the benefits specifically of olive oil. Our search found:
• 0 meta-analyses or systematic reviews
• 1 randomized controlled trial (with results from multiple trial sites)
• 2 observational studies
• Multiple preclinical studies
A randomized controlled trial of older adults at risk of cardiovascular disease compared a low-fat diet to the Mediterranean diet supplemented with either extra-virgin olive oil or nuts. Over four years, the people assigned to the Mediterranean diet supplemented with extra-virgin olive oil showed a slight, but significant, cognitive improvement. The results were not consistent for protection from mild cognitive impairment or dementia [2-5]. Two observational studies also reported that olive oil was associated with slightly improved cognitive function .
These studies suggest that olive oil may slightly promote cognitive fitness. However, in the randomized controlled trial, the Mediterranean diet plus olive oil group was significantly different from the low-fat group but not from the Mediterranean diet plus nuts group. In other words, the best evidence to-date is not for olive oil alone but for the Mediterranean diet, which typically includes olive oil.
In one clinical trial, a Mediterranean diet intervention appeared to benefit both APOE carriers and non-carriers . For more information on what the APOE4 gene allele means for your health, read our APOE4 information page.
No clinical research has studied whether olive oil can benefit patients with dementia.
Studies of olive oil have reported no significant adverse effects, although excessive olive oil consumption may result in mild temporary diarrhea . Though olive oil is one of the safer cooking oils, when heated past its smoke point, it may release volatile organic compounds and lose some of its beneficial content .
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
Olive oil is widely available in varying grades and qualities. Components of olive oil (e.g., oleuropein, oleocanthal) are also available as supplements. The exact dose that may provide cognitive benefit is unknown. Extra virgin olive oil may be more beneficial than refined olive oil because of its increased beneficial phenolic content . Olive oil is a pure fat and therefore should not be consumed in excess.
The Olive Oil Scam: If 80% Is Fake, Why Do You Keep Buying It? — Forbes Magazine
The History of the Mediterranean Diet Pyramid — Oldways
Three Promising Diets to Improve Cognitive Vitality