Clinical Trial Reveals Benefits of Polyphenol Rich Olive Oil for Older Adults With Cognitive Impairment

The MICOIL pilot study was published on November 10th 2020 in the Journal of Alzheimer’s Disease. The trial validated that the long-standing benefits of polyphenol-rich olive oil against cognitive impairment are greater than the benefits of “simple” extra virgin olive oil.

What Was the Objective of the MICOIL Study?

After years of research, we can safely say that the Mediterranean Diet (MD) is one of the healthiest diets out there. In addition, previous studies have shown that a diet rich in extra virgin olive oil (EVOO) may help prevent Alzheimer’s disease (AD).

However, the Mediterranean Diet is not a strictly specific diet, rather than an umbrella-term diet with multiple variations depending on which part of the Mediterranean basin you find yourself in.

It is known that one of the core features of the Mediterranean Diet is the increased consumption of EVOO, even up to four tablespoons per day. The phenolic profile of EVOO is one of those variations that play a significant role on the overall health benefits of this diet.

The MICOIL pilot study aims at revealing the role of the phenolic content of extra virgin olive oil against mild cognitive impairment, in the context of the Mediterranean Diet.

What Was the Methodology of the Clinical Trial?

The clinical trial divided participants with mild cognitive impairment (MCI) in three randomized groups. Genetic predisposition to Alzheimer’s disease was taken into account to form a homogenous baseline. Each group followed a unique diet:


Group 1: High-Phenolic EVOO

The first group received 50ml of high polyphenol olive oil per day, while following the Mediterranean Diet.


Group 2: Moderate-Phenolic EVOO

The second group received 50ml of moderate phenolic olive oil per day, along with the Mediterranean Diet.


Group 3: Mediterranean Diet

The third group did not receive olive oil with increased polyphenol content, but only followed the Mediterranean Diet.

What Were the Results of the Clinical Trial?

Both Group 1 and Group 2 demonstrated significant improvements when compared to Group 3. Specifically, Groups 1 and 2 performed better on ADAS-cog, MMSE, Digit Span and Letter Fluency tests. A significant improvement was seen in the case of genetic predisposition (APOEɛ4 ). Improvements can be seen as P values (calculated probability) below:



Digit Span

Letter Fluency



Long-term consumption of early harvest high phenolic olive oil or moderate phenolic olive oil was associated with significant improvement in cognitive function compared to Mediterranean Diet, independent of the presence of genetic predisposition.

A Word From the Researchers

Until today, there is no other study which has examined in such a detailed manner the effects of Greek extra virgin olive oil in elders with amnestic mild cognitive impairment as an effective solution.”

Magda Tsolaki

Neurologist / Psychiatrist / President of Greek Association of Alzheimer’s Disease and Related Disorders, [1], [2]

Prokopios Magiatis

Associate Professor of Pharmacognosy and Natural Products Chemistry / General Secretary of World Olive Center for Health, [3]

Niki Petridou

BSc Psychology / Systemic Psychotherapist, [2]

Irene Tabakis


Iordanis Saoulidis


Eleni Melliou

Chemist and Food Scientist with PhD in Pharmacognosy and Natural Product Chemistry / President of World Olive Center for Health, [3]

Eftychia Lazarou

Philologist / Clinical Research Associate / PhD Candidate, [2]

Mahi Kozori

Psychologist, [2]

Ioulietta Lazarou

Psychologist / Clinical Research Associate II / PhD candidate in Neuroscience, [1]

Maria Karakota




Department of Neurology General University Hopsital “AHEPA”, Medical School, Faculty of Health Sciences, Aristotle University of Thessaloniki, Makedonia, Greece.



Greek Association of Alzheimer’s Disease and Related Disorders, Thessaloniki, Makedonia, Greece.



Department of Pharmacognosy and Natural Products Chemistry, Faculty of Pharmacy, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens, Greece.