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✍🏻 Ruby Allen | Neuroscience student at the University of Leeds
What is Alzheimer's disease (AD)? 🧠
AD is the most common cause of dementia, accounting for around 70% of cases.
- Memory loss
- Confusion
- Language/understanding problems
- Behavioural changes
Age is the greatest risk factor for AD with the disease typically affecting individuals over 65 years of age.
Globally AD and other dementias affect at least 55 million people – someone in the world develops dementia every 3 seconds.
AD is currently the only leading cause of death in which the incidence is continuing to rise, with the number of cases expected to double every 20 years.
What causes AD? 🏥
In rare cases AD is inherited, although for the majority the causes are unclear.
A key feature of the disease is a build-up of proteins called amyloid b and tau which accumulate and form larger structures called plaques and tangles.
These can interfere with the functioning of the brain and over time certain brain regions can become smaller due to cell death.
Can we prevent AD without pharmaceuticals? 🙆🏻♀️
There is currently no cure for AD so research has increasingly been aimed at developing methods to delay the onset and slow the progression of the disease.
It has been estimated that 35-40% of dementia cases could result from lifestyle factors such as:
Low physical activity
Social isolation
Low education level
Hypertension (high blood pressure)
Obesity
Hearing loss
Depression
Diabetes
Smoking
Therefore, making certain lifestyle changes could lower the number of individuals developing the disease and push back the age of onset.
How can exercise impact the onset of AD? 🏃🏼♀️
Exercise is a key life style factor that could impact the onset of AD.
Studies have shown exercise could be beneficial in AD by:
Increasing blood flow to various brain regions (including the hippocampus; a region involved in memory)
Decreasing the number of amyloid beta and tau proteins
Decreasing inflammatory substances
Promoting the production of anti-inflammatory substances
Stimulating the production of new neurones (a type of brain cell)
Overall, these effects could prevent the cognitive decline seen in individuals with AD.
In a sample of 716 elderly individuals, participants with low daily activity had a 53% higher chance of developing AD.
A review of 24 research papers investigating the impact of exercise on AD showed that resistance exercise (exercise where muscles are contracted against an external resistance, e.g. weightlifting) was the best form of exercise to improve cognition and memory function.
Researchers from the Federal University of São Paulo and the University of São Paulo found that resistance exercise reduced the number of amyloid beta plaques and decreased stress hormone levels which could be beneficial for alleviating the cognitive decline in people with AD.
Aerobic exercise, such as running and cycling, has shown variable effects in elderly individuals (60-80 years). This is likely due to the inability of these individuals to perform this type of exercise at a higher intensity (e.g. it would be difficult for an 80-year-old old running or cycling for sufficient duration).
However, aerobic exercise has shown improvements in memory test results from cognitively healthy and mild cognitive impairment (early stage AD) individuals suggesting that aerobic exercise could reverse early stages and potentially stop the onset of the disease.
In summary, implementing exercise routines into the lives of people with AD could improve their quality of life and brain health and has the potential to reverse their symptoms – particularly resistance training as this could be implemented for those with limited physical abilities and has been shown to have a greater effect. Additionally, physical activity should be carried out regularly by younger individuals to reduce the risk of developing the disease.
How can diet impact the onset of AD? 🍟
Individuals with type 2 diabetes and those who consume a “western diet” (high sugar, fat, and cholesterol, alongside ultra-processed foods) have an increased risk of developing AD.
These diets can impact the gut microbiota which has been linked to cognitive function.
Studies have shown that high sugar and cholesterol levels can increase amyloid b protein production which could contribute to worsening Alzheimer’s progression and increase inflammation in the brain.
Following a Mediterranean diet or a ketogenic diet, as well as taking omega-3 and probiotic supplements, has been shown to delay Alzheimer’s symptoms and improve cognitive function in individuals with early-stage Alzheimer’s disease.
Fruit and vegetables
Whole grains
Legumes
Healthy fats
Moderate seafood
Low dairy
Low red and processed meats
Red wine in moderation
Reduced ultra-processed foods
How can social interactions impact the onset of AD? 👋🏻
Social isolation or poor-quality social interactions have been linked to an increased risk of AD.
Individuals with greater loneliness showed increased:
Amyloid b protein levels
Numbers of tau protein tangles
Inflammation in the brain
Cognitive function was higher in individuals with larger social networks.
Similarly, when investigating this relationship between social interactions and AD, Alzheimer’s disease mouse models showed increased amyloid beta plaque formation along with earlier and worsened memory decline in mice housed away from other mice.
People with AD are at risk from becoming socially isolated due to their symptoms; this can often cause their symptoms to worsen quicker than if social interactions were maintained.
What does the future of AD treatment look like? 🔮
While more research is required, evidence strongly suggests that certain lifestyle changes could reduce the number of people suffering with this disease and could alleviate symptoms for those affected.
A combination of the lifestyle improvements reviewed here appears to be the most effective approach to improving brain health.
Final thought: Here is a podcast speaking with Jim Kwik, a famous brain coach, discussing ideas on how we can improve our memory.
Written by: Ruby Allen (Content Writer)
Edited by: Grace Pountney (Founder and Director)
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