Dementia: Overview

Dementia is our most-feared illness - more than cancer, heart disease, and metabolic disorders combined. It is a debilitating state in which the sufferer's brain cells die, leaving them unable to remember, think clearly, or make decisions about simple everyday tasks (see Figure 1 for an overview of the mechanistic causes of a common dementia). It brings a progressive disorientation, confusion, and errasure of self.

Dementia is a major cause of disability and dependency among older individuals, costing global economies $1.3 trillion - most of which goes to carers who provide an average five hours of care per day. Its psychological costs? Immeasurable. Is there anything more painful? It ranks first among the most-feared diseases and 7th among the leading causes of death worldwide.

Figure 1 (from (1): Fundamental pathological features and molecular mechanisms implicated in the progression of Alzheimer's disease.

Alzheimer's disease, named after the German psychiatrist Alois Alzheimer, is the most common and best-known form of dementia, accounting for 60-80% of all cases. Other types include vascular dementia, Lewy body dementia, and frontotemporal dementia. Of the 57 million people with dementia worldwide (2), about 7 live in the United States with Alzheimer's. Unfortunately, these numbers are expected to more than double over the next 20 to 30 years (3).

Women are more likely than men to develop dementia. Other risk factors include:

• Age - Risk increases substantially after 60.
• Genetics
• High blood pressure
• High blood sugar
• Being overweight or obese
• Smoking
• Excessive drinking
• Bad sleep hygiene
• Physical inactivity
• Social isolation
• Hearing loss
• Depression

Until very recently, virtually all drugs for diseases like Alzheimer's were purely symptomatic - acting to boost neurotransmitter levels in the dying brain in the hope of temporarily improving memory. Newer therapies, such as monoclonal antibodies, are thankfully on the horizon, with some showing promising results in slowing cognitive decline (4).

Nonetheless, while medical science evolves and develops more effective treatments, our best strategy for avoiding dementia remains prevention. This means taking active steps to shift the odds in our favour. 

Some of the risk factors mentioned above are non-modifiable, but most are. Let's delve into what can be done to reduce the risk of dementia and maintain a healthy mind into old age.

Preventative Interventions

The astute reader will have noticed a common thread running through many of the risk factors listed above: good diet, physical activity, good sleep, and social engagement. Together, these four pillars form the foundation of dementia prevention. Thus, aim for:

• A reasonably good diet, ideally including elements from the Mediterranean pattern.
• Daily walks and two to three weekly workout sessions.
• Seven to eight hours of sleep per night.
• Active engagement with your family, friends, and local community.

What else can we do? Well, as the title suggests - grab your tablespoon and get ready to consume some olive oil.

Olive Oil Strikes Again

Tessier et al. (5) analyzed data from two large prospective studies of 92,383 American adults collected between 1990 to 2024. Among other things, the authors investigated the effects of olive oil consumption on participants' risk of dementia.

They grouped their participants into four categories based on daily olive oil intake:

• Control group (baseline): Never or less than once a month.
• Group 1: ≤ 4.5 g (~1 tablespoon) per day.
• Group 2: 4.5 - 7 g (~1.5 teaspoons) per day.
• Group 3: > 7 g (> ~1.5 teaspoons) per day.

Their results were striking. Participants consuming more than 1.5 teaspoons (roughly a tablespoon) of olive oil per day had a 28% lower risk of dying from dementia compared to the baseline group. Moreover, substituting olive oil for margarine and mayonnaise was associated with a lower risk dementia-related death risk regardless of overall diet quality.

That is not trivial: even participants with poor diets benefited simply by using olive oil instead of fats like margarine and mayonnaise.

Time and again, olive oil proves to be the elixir that supports overall health balance and fends off all kinds of diseases - including, as this study showed, dementia. 

Why Olive Oil Works

The likely reason? Olive oil - particularly, high-phenolic olive oil - contains over 30 polyphenols: potent antioxidants with neuroprotective properties.

Supporting this, Cordero et al. (6) demonstrated that Oleuropein, a polyphenol found in olive oil and olive leaf extract, reduced the accumulation of protein aggregates (amyloid plaques; see Figures 1 and 2) in the brain. These plaques, made up of extra-neuronal deposits of amyloid beta (Aβ), are strongly associated with the neurodegeneration observed in Alzheimer's disease.

In fact, these are the same plaques that some of the modern monoclonal antibody treatments now aim to target and clear. So don't wait up for the pharmaceutical industry to catch up to ancient wisdom - keep your brain healthy and safe. Start consuming olive oil today.

Figure 2 (from (1)): Neuropathological key features of Alzheimer's disease contrasted with the neuroprotective effects of extra virgin olive oil and phenolic compounds.

References

1) Alkhalifa AE, Al-Ghraiybah NF, Kaddoumi A. Extra-Virgin Olive Oil in Alzheimer's Disease: A Comprehensive Review of Cellular, Animal, and Clinical Studies. Int J Mol Sci. 2024 Feb 5;25(3):1914. doi: 10.3390/ijms25031914. PMID: 38339193; PMCID: PMC10856527.

2) https://www.who.int/news-room/fact-sheets/detail/dementia

3) https://alz-journals.onlinelibrary.wiley.com/doi/10.1002/alz.13809

4) Cummings J, Osse AML, Cammann D, Powell J, Chen J. Anti-Amyloid Monoclonal Antibodies for the Treatment of Alzheimer's Disease. BioDrugs. 2024 Jan;38(1):5-22. doi: 10.1007/s40259-023-00633-2. Epub 2023 Nov 13. PMID: 37955845; PMCID: PMC10789674.

5) Tessier AJ, Cortese M, Yuan C, Bjornevik K, Ascherio A, Wang DD, Chavarro JE, Stampfer MJ, Hu FB, Willett WC, Guasch-Ferré M. Consumption of Olive Oil and Diet Quality and Risk of Dementia-Related Death. JAMA Netw Open. 2024 May 1;7(5):e2410021. doi: 10.1001/jamanetworkopen.2024.10021. Erratum in: JAMA Netw Open. 2024 Jun 3;7(6):e2424366. doi: 10.1001/jamanetworkopen.2024.24366. PMID: 38709531; PMCID: PMC11074805.

6) Cordero JG, García-Escudero R, Avila J, Gargini R, García-Escudero V. Benefit of Oleuropein Aglycone for Alzheimer's Disease by Promoting Autophagy. Oxid Med Cell Longev. 2018 Feb 20;2018:5010741. doi: 10.1155/2018/5010741. PMID: 29675133; PMCID: PMC5838478.