Written by Taylor Woosley, Staff Writer. 6 months daily consumption of 30 mL extra virgin olive oil significantly reduced p-tau 181 levels (p=0.05) and blood-brain barrier permeability (p<0.05), and improved WMS-IV logical memory test scores (p=0.05). 

olive oilThe rapid aging of the global population is resulting in an increasing prevalence of mild cognitive impairment (MCI) and neurodegenerative disorders1. MCI is an intermediate stage between normal cognition and dementia characterized by a reduction in memory and/or other cognitive processes2. It affects 10-15% of the population over the age of 65 and there is a 5-10% annual rate of progression to dementia in those with MCI, which is much higher than the 1-2% incidence per year among the general population3.

Recent evidence supports a protective effect of extra-virgin olive oil (EVOO) and its phenolic compounds against mitochondrial oxidative stress and neuroinflammation4. It has been observed that the blood brain barrier (BBB) breaks down in the early stage of cognitive dysfunction5. Research findings demonstrate that EVOO restored the BBB function and reduced Alzheimer’s disease-associated pathology by reducing Aβ production and decreased total tau6.

Kaddoumi et al. conducted a pilot study to evaluate the effect of EVOO in MCI participants and compare its effect with refined olive oil (ROO) using various metrics such as BBB integrity and brain function through MRI imaging, cognitive function using neuropsychological evaluation, and changes in specific blood levels. Subjects (n=25) aged between 55 and 75 years with mild cognitive impairment with Mini-Mental State Examination (MMSE) scores between 24-30 and/or a Clinical Dementia Rating (CDR) score of 0.5 were included in the study. Subjects were randomly assigned to either the EVOO (n=13) or ROO group (n=12). The EVOO group was administered 30 mL of The Governor EVOO containing 1200 mg/kg of total polyphenols daily for 6 months. The ROO group received 30 mL daily of refined olive oil containing a null level of polyphenols for the study duration.

Participants had fasted blood samples collected at baseline and after 6 months to determine plasma concentrations of Aβ40, Aβ42, tau, p-tau181, and serum NFL. At the end of the study, subjects were reassessed for changes in cognition function between baseline and 6 months using MMSE, CDR, and Wechsler Memory Scale Fourth Edition (WMS-IV) scores. Changes of BBB permeability and brain function was evaluated using contrast-enhanced MRI and fMRI, respectively. A 2-way ANOVA was performed with group and time as the two main factors for derivatives of imaging data. A one-sample t-test was utilized to assess changes in outcomes and biomarkers within treatment groups. Differences in baseline outcomes and biomarkers were tested using a two-sample t-test.

Male participants represented 32% of total participation. Study groups were not statistically significantly different in their average age, body weight, education, MMSE, and CDR. Furthermore, the two groups had statistically similar connectivity values at baseline. Significant findings of the study are as follows:

  • After 6 months, the EVOO group demonstrated a significant reduction in BBB permeability in the individual medial temporal lobe regions, which also showed a group x session interaction effect (p<0.05, FDR corrected for multiple comparisons) suggesting the effect could be specific to EVOO compared to ROO.
  • Six months after daily consumption, the EVOO group demonstrated improvement in the CDR rating by -0.154 (-0.299, -0.0087; p=0.0395) with 31% of subjects who scored 0.5 at baseline scoring 0.
  • For the WMS-IV logical memory test, a significant difference between baseline and after 6 months of EVOO consumption was observed and the overall score increased by 2.034 points (0.0127, 4.08; p=0.05) and LM-II by 13.45 (0.901, 25.99; p=0.0377) suggesting improved memory.

Results of the study show that daily consumption of EVOO reduced BBB permeability and enhanced brain function and memory in subjects with MCI. Further research should continue to explore the neuroprotective effects of EVOO. Study limitations include the small sample size, the lack of control groups including MCI subjects who did not receive olive oil to compare brain function and blood AD biomarkers, and the short duration of the study.

Source: Kaddoumi, Amal, Thomas S. Denney Jr, Gopikrishna Deshpande, Jennifer L. Robinson, Ronald J. Beyers, David T. Redden, Domenico Praticò et al. “Extra-Virgin Olive Oil Enhances the Blood–Brain Barrier Function in Mild Cognitive Impairment: A Randomized Controlled Trial.” Nutrients 14, no. 23 (2022): 5102.

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Posted January 24, 2023.

Taylor Woosley studied biology at Purdue University before becoming a 2016 graduate of Columbia College Chicago with a major in Writing. She currently resides in Glen Ellyn, IL.

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