What does APOE really mean for your brain health?
Genes are just one of many risk factors for dementia and Alzheimer’s, but I find they’re often misunderstood. We tend to think that since our genes can’t be changed, that they seal our fate, but this is not always the case.
The difference between family history, genetic variations and genetic mutations can be hard to grasp when you’re not a genetic scientist!
So, in this article, I aim to clear a little bit of this up and, hopefully, help to highlight that when it comes to Dementia and Alzheimer’s, our genes don’t seal our fate – we are so much more than our genes! Even an APOE4 result is not a sentence – the way we eat, move and live holds the real power over our future.
GENES AND ALZHEIMER’S
Although many people have a family history of Alzheimer’s only around 1% directly inherit a gene mutation from their parents which causes a rare, early onset, aggressive form of Alzheimer’s. This is known as Familial Alzheimer’s Disease (FAD) and is present in certain family groups around the world. It involves a specific mutation on one of 3 genes known as APP, presenilin 1 and presenilin 2.
But many other gene variations can influence your risk of dementia and alzheimer’s – just as certain gene variations can influence your risk of cardiovascular disease, diabetes and depression too. These genes might make it more likely that you’ll develop a disease, but only with the right mix of other factors.
The one gene with the strongest correlation to Alzheimer’s risk is the APOE gene. We all have this gene (unlike the rare mutation above), and there are different variations of this gene that you can have and some increase your risk, while some may actually be protective.
ALL ABOUT THE APOE GENE
There are 3 types/variations of APOE gene that a person can have: E2, E3 or E4.
We get 2 copies of this gene – one from our mother and one from our father. So each person will have a combination of these variants, thus the possible combinations are:
No copies of E4:
E2 / E2
E2 / E3
E3 / E3
1 copy of E4
E3 / E4
E4 / E2
2 copies of E4
E4 / E4
APOE2 is the least common and having this gene reduces your risk of Alzheimer’s but doesn’t necessarily offer guaranteed protection. There’s a lot more at play as you’ll see!
APOE3 is the most common and is often considered neutral – it doesn’t seem to increase or decrease your risk.
APOE4 increases your risk of Coronary Artery disease and Alzheimer’s Disease.
Different variants are more or less common in certain populations (for example APOE4 is more common in Pygmies, whereas APOE 2 is absent in Native Americans) and different variants can affect people in different ways (for example, having one copy of the E4 allele may pose more risk to women while having two copies seems to affect men and women similarly).
It is so important to remember that APOE4 is just one of many risk factors for dementia.
Having an APOE4 gene variant does NOT seal your fate and doom you to a future Alzheimer’s diagnosis.
WHAT DOES APOE DO IN THE BODY?
The APOE gene gives instructions to a protein called Apolipoprotein E or APOE. APOE is involved in the transport of cholesterol and other lipids (fats) that are involved in brain structure and functioning.
APOE Outside of the brain
E4 variants can increase the risk of stroke and atherosclerosis (hardening of the arteries)
APOE inside of the brain
The APOE protein is involved in clearing Amyloid from the brain. It is amyloid that is in the plaques that build up and are a hallmark of Alzheimer’s disease.
Different gene variants clear amyloid in different ways – E2 seems to clear it more efficiently, while E4 doesn’t carry out this function very well, meaning plaques have more opportunity to build up in these E4 carriers. E3 sits somewhere in the middle.
Remember I said APOE is involved in lipid (fat) transport in the body too? Well in E4 carriers, the beneficial fats that our brain relies on may have a harder time getting into the brain cells where they’re needed. The less helpful ones tend to get in much more easily, so the brain can end up a little deficient in these essential fats which can increase the risk for cognitive decline and dementia.
WHY YOUR GENES DON’T SEAL YOUR FATE
BUT, not everyone who carries E4 variants will get Dementia or Alzheimer’s. Of the people that have Alzheimer’s, somewhere between 40-65% of people with Alzheimer’s have the E4 variant. That means that almost half of those with Alzheimer’s have the low risk or neutral genes.
Having “high risk” genes doesn’t seal your fate, and having “low risk” genes doesn’t guarantee your immunity either.
The buildup of plaques and essential fat deficiency doesn’t happen in ALL people with E4 variants, and having E2 variants doesn’t make you immune to the plaques and deficiencies either.
Other factors in our environment and diet need to be present to create the perfect storm that leads to the development of cognitive decline, dementia and Alzheimer’s.
In fact, this increased risk from E4 variants may be modified by various diet and lifestyle measures. If you provide optimal nutrients and conditions for your body to function in, you may be able to mitigate some of the risk from your genes. In the same way, if you eat a diet lacking in essential nutrients, high in inflammatory foods and trans fats, you’re at greater risk of dementia, regardless of your genes.
WHAT TO DO IF YOU KNOW YOUR GENES
Knowing what genes you carry shouldn’t be a source of fear.
If you’re aware that you have higher risk genes, that’s very valuable information! Now you can get to work making improvements in your diet and lifestyle to ensure your body and brain is getting everything it needs and to counteract that risk.
And if you’ve discovered you have low-risk genes – that isn’t a free pass to eat terribly and ignore your health markers. Things like increased inflammation, sub-optimal nutrients, blood sugar issues and being overweight can all drastically increase your risk of Dementia and Alzheimer’s, regardless of your genes, so make sure you’re still taking the right steps to eat, move and live better for the sake of your brain.
So – your genes are nothing to be afraid of! In fact, knowing what genes you have can help you to personalise your brain protection plan and ensure you’re modififying your diet and lifestyle in just the right way for your genes, so that you can keep your brain happy and healthy until you’re over 100!
I know some of you reading this may already know that you are an E4 carrier.
So what to do?
Firstly, working alongside a brain health practitioner is important to understand your compounding risk factors, develop a personalised plan and keep an eye on the right biomarkers to ensure you’re keeping everything within healthy ranges. But, here are some generalised top tips to consider starting with if you have the APOE4 variant:
- Do regular, moderate-intensity exercise
- Eat a low saturated fat diet with higher intake of omega 3 – specifically DHA. (The more of these in the diet, the more available for the cells to take up, even if the E4 variant means this is done less efficiently)
- Increase antioxidant and phytonutrient-rich foods (some food like turmeric have been labelled “anti-Alzheimer’s” because their phytonutrients help to clear amyloid buildup.
- Avoid other proinflammatory triggers like smoking, poor gut health, chemicals. high alcohol consumption, and being overweight.
P.S. Regardless of your genes, your nutrition and lifestyle holds incredible power over the future of your brain. If you’re ready to take your health into your own hands then check out the Nourished Brain Academy. We’ll help you build a more brain health life (based on science) one habit at a time.