a photo of part of a tin of Yanni's Finest olive oil on the right, the MICOIL study logo on the left, and text in between saying "seven scientific articles and a clinical trial show how EVOO can help fight off mild cognitive impairment and Alzheimer's disease"

The U.S. Food and Drug Administration (FDA) has approved a controversial drug that may slow cognitive decline in patients in the early stages of Alzheimer’s. Uncertainty about the drug’s efficacy and cost and concern about the possibility of serious side effects led three FDA advisory committee members to resign. Could extra virgin olive oil do better?

In the Mediterranean region, olive oil has been consumed safely and hailed for its health benefits for millennia. In recent years, researchers have been exploring olive oil’s potential to help prevent and treat various illnesses. Now concluding, the six-year MICOIL study was the first in the world to test extra virgin olive oil (EVOO) in a clinical trial in humans with mild cognitive impairment (MCI). MCI is the decline in thinking skills characteristic of an early stage of Alzheimer’s, before the more severe symptoms associated with the disease appear.  

The FDA-approved drug aducanumab, which must be administered intravenously, was also used to treat patients with MCI in clinical trials. Lacking any cure for Alzheimer's, scientists have been striving to discover new ways to manage the MCI due to Alzheimer’s disease and prevent it from progressing. Now seven scientific publications related to the MICOIL study provide several different types of evidence that extra virgin olive oil can delay the onset of Alzheimer’s in humans, without any negative side effects.  

While MICOIL included only a small number of patients, making additional clinical trials essential to further test its results, the evidence gathered to date suggests that EVOO might offer significant advantages over the FDA-approved drug in terms of effectiveness, cost, ease of use, and safety. Anastasia Pantazaki, one of the researchers involved with MICOIL, explained to Greek Liquid Gold that study results indicate that a long-term diet rich in EVOO can help protect against mild cognitive impairment and Alzheimer's disease.

MICOIL also revealed that consumption of EVOO with moderate to high amounts of the natural plant compounds called phenols could provide even more benefits than low-phenolic olive oil. As Magda Tsolaki and her coauthors indicated, the study showed that one year of consumption of high-phenolic or moderate-phenolic EVOO “was associated with a significant improvement in cognitive function.” 

The MICOIL team observed that MCI patients who consumed 50 ml of EVOO per day for a year had decreased levels of the proteins in their blood that indicate the presence of Alzheimer’s. On the other hand, a control group of MCI patients who did not consume EVOO had “hallmark" protein levels nearly as high as those of Alzheimer's patients.

Clinical trial results published by MICOIL researchers in Experimental Gerontology in 2020 support the argument that extra virgin olive oil has potential as an alternative therapy for preventing the onset of Alzheimer’s disease (AD). Researchers found that levels of the neuroprotective protein BMI1 increased in MCI patients treated with EVOO for 12 months, while AD biomarkers returned to normal levels, and oxidative stress and inflammation were reduced. Elena E. Tzekaki and her colleagues hope their study will have an impact on the design of future therapeutic strategies for AD prevention.

In a 2021 article, Stavros I. Dimitriadis and his co-authors “further validated the improved cognitive measures published in the original MICOIL study (Tsolaki et al., 2020) by analysing the EEG resting-state recordings of a specific subgroup of subjects.” They showed that a “non-pharmaceutical intervention” based on high phenolic early harvest extra virgin olive oil “in MCI reduces the over-excitation of information flow” and “increases the human brain flexibility.” That is, high phenolic EVOO helps the brain work better.

A biochemical study following up on MICOIL’s clinical trial also found that the well-established AD hallmarks (Aβ1-40 and Aβ1-42 species, tau, and p-tau) of the group of MCI patients who consumed EVOO for one year “were restored to levels equal to those of the cognitively-healthy group,” while those who did not eat EVOO had their AD biomarker levels increase. Unsurprisingly, given EVOO’s known antioxidant compounds, patients eating EVOO also showed less evidence of oxidative stress, while those who did not use EVOO showed more oxidative stress. It is well known that neuroinflammation and oxidative stress are two of the main causes of Alzheimer’s and other neurodegenerative diseases. According to the study authors, their results imply that natural products such as extra virgin olive oil might be used to prevent AD.

A 2021 review article on “The multifunctional therapeutic potentiality of Extra Virgin Olive Oil” refers to many studies that have proven “that the consumption of olive oil was associated with better overall health,” most often with reference to the phenolic compounds they contain. The studies reviewed indicate that “the regular intake of EVOO is associated with enhanced neuroprotective, antioxidant, anti-inflammatory, anti-atherosclerotic, anti-cancer and anti-microbial properties.”

The review article concludes that EVOO has been proven “to overcome the hurdle of amyloid deposition (in vitro and in animal models) and to delay the cognitive decline among non-demented older individuals,” among many other benefits. As the scientists emphasize, “further investigation in a bigger cohort of human patients is demanded for acquiring warranties certifying this treasure as a natural and alternative, less toxic therapy for numerous disorders worldwide.”

Evi Psounou Prodromou, who donated Yanni’s Olive Grove’s extra virgin olive oil for the MICOIL clinical trial, was impressed by the efforts of the interdisciplinary group of Greek scientists and researchers, who work in such areas as psychology, neurology, biochemistry, pharmacology, and food chemistry. “All from a small country with limited financial power, but with a great attitude, perseverance, and (most important) a great belief in natural high quality Greek products.”

Prodromou would like to “make people all over the world understand the importance of the results regarding the benefits of EVOO consumption.” She refers to Hippocrates, “the father of medicine, who said 2500 years ago, ‘Let food be your medicine, and medicine be your food.’ That means we should eat as healthily as we can to live a long, healthy life. In other words, a healthy, balanced diet helps prevent diseases!”

MICOIL’s multi-paper study partners were the Greek Association of Alzheimer’s Disease and Related Disorders (Alzheimer Hellas), the World Olive Center for Health, Aristotle University of Thessaloniki in Greece, the National Kapodistrian University in Athens, and the olive oil production company Yanni’s Olive Grove.

Published in the Hellenic Journal of Nuclear Medicine in 2019, the article about the initial MICOIL study findings won second prize at the 5th International Medical Olympiad sponsored by the Greek Ministry of Health and the Medical School of the University of Thessaloniki.

Thanks to Evi Psounou Prodromou for the images that appear with this article.

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