Could the addition of EVOO to daily diet prevents, treats, and/or holds AD progression? If yes, why and by what mechanism(s)?
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder of the elderly that afflicts about 30 million patients globally.1 Although the pathogenesis of AD is complex, it involves two well-defined pathologies, amyloid-β (Aβ) and tau-related neuropathologies.2 Amyloid-related neuropathological alterations in the brain are due to accumulation and deposition of Aβ peptides.3 Amyloid peptides, mainly Aβ40 and Aβ42, accumulate in the brain tissue and vasculature of the brain where they assemble and form insoluble plaques, a major hallmark found in the brains of AD patients, as well as soluble oligomers.3,4 The tau-related neuropathological alterations are stimulated by somatodendritic buildup of hyper-phosphorylated tau, which prevents tau assembly onto microtubules and results in intracellular insoluble neurofibrillary tangles (NFTs).6
Extra-virgin olive oil (EVOO)
Diet is a probable risk factor that by modification could reduce or delay the onset of AD. Several epidemiological and clinical studies suggested that adherence to Mediterranean diet improves cognitive function and slows the progression of AD.6-8 Daily consumption of EVOO is one of the characteristic elements of a Mediterranean diet. Dietary consumption of EVOO ranges from 40 to 50 g/day with the highest daily intake among Greeks. The composition of EVOO is primarily monounsaturated fatty acids (~95%) and phenolic compounds (~5%).9,10 Among EVOO phenolics, oleocanthal which is responsible for the bitter and pungent taste of EVOO has shown anti-inflammatory and antioxidant properties similar to the nonsteroidal anti-inflammatory drug ibuprofen.11
EVOO, oleocanthal and AD
While EVOO beneficial effects were previously reported, the mechanism(s) by which its addition to diet could improve cognitive function was not thoroughly evaluated. Besides, studies focused on studying oleocanthal health benefits against AD were never evaluated in AD models.
Using in vitro and in vivo models complemented with several experimental tools and protocols, studies from my laboratory demonstrated EVOO and oleocanthal are highly efficacious, possess neuroprotective effect against AD and improve cognitive function in AD mouse models.12-16 Further mechanistic studies explained such positive effects as following:
- EVOO and its bioactive component oleocanthal enhanced the integrity and functionality of the blood-brain barrier (BBB) which is important to maintain healthy brain.
- EVOO and oleocanthal increased Ab clearance across the BBB.
- Both EVOO and oleocanthal increased the expression of proteins involved in ApoE-dependent clearance pathway and degradation enzymes of Aβ.
- EVOO and oleocanthal reduced astrocytes activation and attenuated neuroinflammatory markers that were associated with neuroprotective effect.
- Besides enhancing its clearance, EVOO reduced the production of Aβ, which further reduced overall Aβ brain load.
- In addition to reducing Aβ brain load, EVOO reduced tau hyper-phosphorylation, another hallmark of AD.
While clinical studies in humans are necessary to translate our findings, our data support EVOO addition to daily diet protects against AD. The beneficial effect of could be explained, at least in part, by oleocanthal that enhances cognitive function by multiple mechanisms.
View article references
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