Actor Chris Hemsworth, best known for his role as the god Thor in Marvel Cinematic Universe films, has announced he is taking a break from acting after being told he has two copies of the APOE4 gene, causing his Alzheimer’s -Risk increased.
Having one copy of the APOE4 gene increases your risk of Alzheimer’s by two to three times.
Two copies increase your risk by 10 to 15 times.
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But the key here is “risk”. The presence of one or more copies of the gene does not guarantee that Chris or anyone else in a similar situation will develop Alzheimer’s, the most common form of dementia.
Hemsworth’s willingness to share his concerns about developing Alzheimer’s with millions should be applauded.
It’s a reminder for all of us to keep an eye on our health and reduce the risk of future illnesses.
Alzheimer’s and dementia more broadly will challenge healthcare systems worldwide.
In Australia alone there are up to 500,000 people with dementia, supported by nearly 1.6 million carers. By 2036, around 450 people are expected to be diagnosed every day. Therefore, understanding how APOE4 alters the risk of the main cause of dementia may be crucial to prevent cases.
But not all people with the APOE4 gene develop Alzheimer’s. This means there can be a combination of environmental factors working with the gene, resulting in some people developing Alzheimer’s while others don’t.
What does APOE4 have to do with Alzheimer’s?
Most Australians have APOE3 or APOE2 genes. In Caucasians, only about 15 percent, like Hemsworth, have inherited an APOE4 gene.
The APOE gene types are best known for their role in modulating the metabolism of lipids (fats) such as cholesterol and triglycerides.
They code for the synthesis of different versions of the protein APOE with subtle differences in structure. The APOE proteins become an integral part of lipoproteins in the blood. These are the fat-bearing particles that your GP measures to account for your heart disease risk.
APOE proteins have a similar function in the brain to modulate lipid levels. But in the context of Alzheimer’s, researchers are studying it for its effect on brain cell integrity.
Mounting evidence suggests that APOE4 is linked to brain inflammation and cell damage.
Can we prevent Alzheimer’s?
1. Take care of your capillaries
Damaged and leaking blood vessels (capillaries) in the brain lead to inflammation, brain cell death, and cognitive impairment. In fact, damaged capillaries in Alzheimer’s are the earliest sign of the type of brain damage that causes disease.
The protein encoded by the APOE4 gene may be less able to support healthy capillaries in the brain. We proposed that APOE4 increases the abundance of specific complexes of lipoproteins and proteins in the blood, which silently damage the brain capillaries, causing them to leak.
We also see more brain capillary leaks in mice fed western diets high in saturated fats.
The relationship between the way the APOE proteins mediate lipid metabolism and capillary health in humans is poorly understood.
But we have 60 years of research to say with confidence that eating foods that are good for the heart should also be good for the brain. This is particularly relevant for people with the APOE4 gene.
So if you have the APOE4 gene and want to minimize your risk of Alzheimer’s, a healthy diet is a good place to start.
2. Give your brain a break
Reducing unnecessary stimuli to “give your brain a break” can have a huge impact for decades of your life. The latter may be a more important consideration if you have the APOE4 gene.
That’s because the APOE gene is also linked to how the brain uses energy, which can lead to more oxidative stress and damage.
While we have yet to gather robust human data, do a digital detox once in a while, schedule some downtime, and avoid unnecessary stress when you can.
Should we test for the APOE4 gene?
Some people may be tempted to get tested for the APOE4 gene, particularly if there is a family history of Alzheimer’s.
But unless genetic testing changes your treatment (such as taking certain medications to slow the progression of brain damage) or behavior to minimize your risk of Alzheimer’s, then testing isn’t warranted.
We cannot change the genes that our parents gave us, but we can change our environment.
Poor diet, every drop of alcohol you drink, obesity and diabetes, high blood pressure and lack of exercise all contribute to poor vascular health over time and increase your risk of dementia.
We’re still learning how these risk factors for Alzheimer’s interact with the APOE4 gene. But there’s no reason why we shouldn’t all now take a greater responsibility for minimizing our risk of dementia, whether or not we have the APOE4 gene.
This article first appeared in The conversation.
John Mamo is a Distinguished Professor of Health Sciences and Director at Curtin University’s Curtin Health Innovation Research Institute.
https://7news.com.au/entertainment/chris-hemsworth/chris-hemsworths-alzheimers-gene-doesnt-guarantee-hell-develop-dementia-heres-what-we-can-all-do-to-reduce-our-risk-c-9013565 Chris Hemsworth’s Alzheimer’s gene does not guarantee he will develop dementia. Here’s what we can all do to reduce our risk