Alzheimer’s Disease: Why are we curious on how it is still cureless?

The recent news of "Thor” star Chris Hemsworth potentially taking a break from his acting career due to his genetic predisposition to Alzheimer’s disease have intrigued many of us. But really, what is Alzheimer’s disease exactly and why can it be so detrimental?

Overview of the “silent killer”

While working on his new docuseries “Limitless”, Australian actor Chris Hemsworth underwent a set of genetic tests and found out that something in his DNA might potentially be a huge danger to his career. It was discovered that his genetic makeup has two copies of the gene APOE4. The said gene has been studied to be associated with a higher risk of Alzheimer’s disease. Interestingly, one in four people carry a single copy, but only as little as 2-3% of the population carry both copies. Before delving deeper into how genetic makeup can impact our risks of getting Alzheimer’s, let’s get to know about this neurodegenerative disease first.

Alzheimer’s disease (AD) is included under the general term of dementia which refers to a declining cognitive ability where it interferes with daily activities under a certain severity. AD accounts for at least two-thirds of dementia cases in people aged 65 or above, with an estimated 55 million people of the global population suffering from it.

AD is a neurodegenerative disease, meaning that it is characterized by the declining of activity or death of cells in the central nervous system, which usually has no cure. As for AD itself, the initial and most found symptom is irregular short-term memory loss and long-term memory sparing. However, the symptoms may range from irregular mood changes to speech/language problems (aphasia) to involuntary passing of urine (urinary incontinence) or stools (bowel incontinence) according to what stage the patient is at.

Now, what actually causes such harmful, or violent symptoms to appear? AD is thought to be caused by the abnormal formation of proteins called amyloid and tau. Amyloid proteins deposit plaques around the brain cells, whereas tau forms tangles within the brain cells. It has been discovered that these abnormal deposits of proteins happen long before the symptoms of AD appear.

Not only brain cells get damaged, but chemical messengers in the brain called neurotransmitters can also decrease. These neurotransmitters function to send signals or messages between brain cells. With the declining of neurotransmitter activity, patients with Alzheimer’s slowly lose cognitive and behavioral ability over time.

Genetic aspects of Alzheimer’s disease

While it is true that AD can be caused by environmental factors such as unhealthy lifestyles, occupational exposure to harmful chemicals, and even socioeconomic status, all these factors could still be within the individual’s control. What is more difficult to control is the genetic aspect, where the risk of getting AD is etched into the individual’s DNA.

In the case of genetic disorders, there are genes of high penetrance and low penetrance. High penetrant genes are more likely to make the individual exhibit symptoms or traits of the disorder, whereas low penetrant genes are less likely to do so. Going back to Chris Hemsworth’s situation, the gene in question is APOE4, which is a rare gene known as a “high penetrant” for Alzheimer’s.

Therefore, it is important to know how penetrant certain genes are to calculate our risks of getting Alzheimer’s disease. But how could that be achieved?

Screening for Alzheimer’s: The key to prevention

With the disease itself discovered back in the 1900s, it is truly intriguing and devastating that so much research has been done to discover a cure, but to no avail until today. However, current treatments are available, most of them in helping to tone down or control the cognitive and behavioral symptoms including cholinesterase inhibitors like galantamine, rivastigmine, and donepezil.

As the saying goes, “prevention is better than treatment”, we sometimes must go the extra mile for diseases like Alzheimer’s. One of the most advanced methods is a genetic screening test. Genetic testing for Alzheimer’s consists of a blood test that can identify APOE gene variants, an important marker for the condition. The gene itself has been frequently used in research to help patients in determining their risk of developing Alzheimer’s as well as scientists to identify early abnormal protein formations in the brain and compare the effectiveness of different treatments according to the profile of APOE in each patient.

Genetic tests can also help physicians in diagnosing early-onset Alzheimer’s disease, especially in people with a history of Alzheimer’s or a similar neurodegenerative disorder. However, genetic testing alone cannot accurately predict the disease, as the development and progression of Alzheimer’s itself are influenced by many other factors. Furthermore, genetic testing enables us to discuss with physicians along with additional actions that can lower the risk.

What can we do for now: Lifestyle change!

Healthy lifestyles are always the key to longevity, as well as being the most major contributors to the prevention of many diseases. According to National Institute of Health (NIH), researchers have narrowed down five healthy lifestyle factors that will reduce the progression of Alzheimer’s.

1. 150 minutes of moderate exercise per week – healthy aging often requires regular physical activity
2. Quit smoking – needless to say, smoking gets more harmful to your body as it ages
3. Limit the use of alcohol – as harmful as the effects of alcohol consumption does to (especially) liver health, it also impacts cognitive health
4. Include more plant-based foods and polyunsaturated fats (PUFA) in your diet and limit consumption of saturated fats (SFA) – diets such as the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet are specially designed to prevent inflammation that will lead to dementia
5. Keep the mind active – doing cognitive activities stimulates and benefits the brain

Currently, WHO has set a deadline to find the cure for Alzheimer’s, which is by the year 2030. While we wait, let’s do our best to take care of our bodies. The preventive measures mentioned above yields the best outcomes when performed early before the first symptoms of dementia appear. Factors such as cognition level, neuropathological changes, and lifestyle can benefit each other to make an individual healthy for a longer time.

NutriReady™ nutrigenetics test by Nalagenetics could help in personalizing your diet, therefore providing your body’s exact needs through a DNA test, all put into a compact report that you could show to your own physician or dietician.

To know more about NutriReady™, click on this link!