Review Explores Olive Oil’s Role in Reducing Cognitive Decline

A recent research review examines how adherence to the Mediterranean diet and consumption of extra virgin olive oil may positively affect cognitive health.

Drawing on meta-analyses of 730,000 participants and recent magnetic resonance imaging evidence, the researchers concluded that many of the mechanisms by which olive oil consumption and the Mediterranean diet promote cardiovascular health and reduce inflammation also mitigate the impacts of mild cognitive impairment, Alzheimer’s disease and vascular dementia.

Parsing the data, the researchers investigated the impacts of Mediterranean diet adherence on cardiovascular risk factors, extra virgin olive oil’s anti-inflammatory and antioxidant effects, the role of olive oil in stroke prevention, and several other health metrics.

“In short, the study shows that olive oil and the Mediterranean diet contain anti-inflammatory polyphenols and other components that create a systemic response to mitigate vascular risk factors while offering direct neuroprotective effects to help prevent the onset of dementia,” said Aitor González-Cidad, the study’s lead author and a sixth-year medical student at the University of the Basque Country.

However, the researchers emphasized the need for additional placebo-controlled clinical trials to confirm the supportive nutritional role of extra virgin olive oil in age-associated cognitive decline in the elderly.

”Future research must determine how these mechanisms translate into clinical practices by isolating extra virgin olive oil and its polyphenols,” they wrote.

Beginning with the role of improving cardiovascular health in cognitive impairment, the researchers found that patients following the Mediterranean diet with extra virgin olive oil had a lower risk of hypertension and obesity, both strongly associated with cardiovascular disease and vascular disease symptoms linked to cognitive impairment.

Furthermore, the researchers indicated that the Mediterranean diet directly influences the main pathogenic factors of one of the major causes of cardiovascular disease, atherosclerosis, which plays a fundamental role in the development of vascular dementia. 

Mediterranean diet adherence achieved this by reducing blood pressure, improving lipid profiles, and reducing inflammation.

The researchers also investigated the role of the Mediterranean diet and extra virgin olive oil on vascular health, the deterioration of which is directly associated with vascular dementia, the second most common type of dementia after Alzheimer’s disease.

According to the scientific literature, cerebrovascular disease, including stroke, chronic cerebral ischemia, and subcortical ischemia small vessel disease, is the primary cause of vascular dementia.

The researchers found that adherence to the Mediterranean diet is linked to prevention of ischemic and hemorrhagic stroke, which in turn reduces vascular dementia incidence, adding that the Mediterranean diet helps preserve cerebrovascular integrity and function by improving these metabolic parameters

The researchers further highlighted the specific role of extra virgin olive oil in this protection, noting that one observational study of 239 ischemic stroke patients showed higher rates of complete arterial recanalization with extra virgin olive oil than with overall Mediterranean diet adherence.

This finding suggested that extra virgin olive oil produced unique vascular effects separate from those obtained with the Mediterranean diet alone.

Separately, the researchers identified the reduction of oxidative stress as among the most significant mechanisms through which the Mediterranean diet and extra virgin olive oil consumption positively impact cognitive health

They noted that oxidative stress is a key contributor to brain aging and neurodegeneration, making it an important target for interventions aimed at slowing cognitive decline. 

The scientific literature has identified that stroke and cerebral ischemia, which occurs when blood flow to the brain is reduced, can further exacerbate oxidative stress and mitochondrial dysfunction, processes associated with neuronal damage and Alzheimer’s disease.

Through their analysis, the researchers found that the Mediterranean diet may help counter these effects through its antioxidant compounds, including vitamins C and E, which reduce oxidative stress and have been linked to improved cognitive outcomes. 

The researchers highlighted the role of oleic acid, hydroxytyrosol, and oleocanthal in reducing oxidative stress, enhancing endothelial function, and modulating inflammatory cascades implicated in cerebral small-vessel disease, which is “intimately related” to the pathogenesis of vascular dementia.

They added that extra virgin olive oil’s positive effects on waist circumference, triglycerides, fasting glucose, high-density lipoprotein (HDL), and systemic inflammatory factors are also directly linked to reduced cerebrovascular risk.

The researchers also found that extra virgin olive oil acts as a potent enhancer of mitochondrial health, increasing ATP generation and improving cognitive scores in rat models.

Furthermore, they added that adherence to the Mediterranean diet has been linked to a lower risk of hemorrhagic strokes due to reduced inflammation and improved endothelial function. Stroke is one of the primary causes of vascular dementia.

Looking specifically at the role of extra virgin olive oil consumption and cognitive impairment, the researchers further confirmed that anti-inflammatory mechanisms from diets rich in monounsaturated fatty acids, antioxidants, and the polyphenols found in extra virgin olive oil significantly decrease interleukin-6, a pro-inflammatory cytokine associated with Alzheimer’s disease.

Demonstrating how extra virgin olive oil’s positive associations with cognitive health are intertwined, the researchers said these compounds improve mitochondrial function, which also reduces oxidative stress and improves endothelial function. 

Improved endothelial function, in turn, switches the body to healthier metabolic phenotypes and modulates the expression of genes related to lipid metabolism and insulin sensitivity, among other mechanisms

Returning to the role of extra virgin olive oil on cognitive impairment, the researchers highlighted that preclinical trials show polyphenols may influence tau hyperphosphorylation and amyloid-beta aggregations, two core pathophysiological mechanisms of Alzheimer’s disease.

The researchers also investigated the relationship between extra virgin olive oil’s polyphenols and cognitive decline. 

They found that hydroxytyrosol, oleocanthal, oleuropein, and luteolin have all been linked in preclinical studies to modulating key Alzheimer’s disease mechanisms.

More specifically, they found that oleocanthal and oleuropein inhibit the assembly of amyloid-beta protein into neurotoxic oligomers and fibrils and facilitate the disaggregation of preformed amyloid structures.

Oleocanthal has also been shown to activate the autophagic process that helps clear cellular debris and improve mitochondrial function, protecting against Alzheimer’s disease.

These polyphenols have similarly reduced tau phosphorylation and aggregation, while other phenolic compounds have been shown to reduce chronic neuroinflammation by decreasing microglial activation and lowering inflammatory cytokine levels.

These phenolic compounds have also been shown to inhibit p38 MAPK pathways, which are involved in oxidative stress and neurodegeneration, and to help break the amyloid toxicity cycle, reducing neural death.

From the highly scientific to the more mundane, the researchers also examined the impact of the Mediterranean diet on sleep and mood.

They found that higher adherence to the Mediterranean diet was associated with improved sleep quality and more stable sleep, “providing a plausible mechanism for neuroprotection,” as poor sleep has been linked to cognitive impairment and dementia risk.

They added that Mediterranean diet adherence improves inflammation and oxidative stress markers, suggesting a beneficial impact on sleep apnea and improved glymphatic circulation during sleep for cognitive function.

With further research on the subject set to be published in the coming months, the researchers said clinicians should take a more serious look at incorporating the Mediterranean diet into treatment programs for people at risk of cognitive impairment.

“The Mediterranean diet should be emphasized by clinicians in future dietary and non-pharmacological strategies specifically designed to mitigate the primary risk factors for dementia,” they wrote.

“While the general benefits of the Mediterranean diet are well documented, there is a need to synthesize the most recent data, dating back to 2020, on the specific neuroprotective mechanisms of extra virgin olive oil and how these interventions correlate with measurable clinical outcomes,” the researchers concluded.