In 2022, Chris Hemsworth, known for his role as Thor in the Marvel Cinematic Universe, revealed his genetic predisposition for Alzheimer’s disease on Disney+ and National Geographic's series Limitless. Hemsworth discovered he carries two copies of the APOE e4 gene, the strongest genetic risk factor for Alzheimer’s disease. His public disclosure sparked widespread discussions about APOE, cognitive longevity, and the impact of lifestyle choices.
The APOE gene encodes a protein that helps carry cholesterol and fats in the bloodstream. There are three versions (alleles) of the APOE gene: e2, e3, and e4. We inherit one copy of the gene from each parent, resulting in combinations like e2/e2, e2/e4, or e3/e3. Your genetic combination (genotype) influences your risk for illness or, conversely, your resilience against it.
e3/e3 is the most common genotype, present in approximately 64% of the population (APO E Gene Online Program). The e2/e2 and e4/e4 combinations are rare, occurring in about 1% and 5% of the population, respectively (APO E Gene Online Program). Research indicates that the e2 allele may protect against cognitive decline, whereas the e4 allele is linked to a higher risk of Alzheimer’s disease. Carrying one e4 allele increases Alzheimer’s risk by 2–3 times. Two copies of the e4 allele—like in Chris Hemsworth’s case—raise the risk by 8–10 times.
While these numbers can seem daunting, it’s important to emphasize that APOE status does not directly cause dementia but rather predisposes individuals to cognitive decline. Your DNA plays a role in shaping your health, but it doesn’t dictate your destiny. There are numerous strategies to reduce the risk of cognitive decline with age, making your cognitive health largely influenced by the choices you make.
e4 is Not a Dementia Sentence
Research shows that various lifestyle habits can effectively support brain health, even in individuals with the e4 gene variant:
Physical Activity
Exercise provides brain-protective benefits and reduces the risk of cognitive decline in e4 carriers (Perez-Lasierra et al., 2021).
Meditation & Social Engagement
Mindfulness practices and regular social interactions help enhance cognitive reserve in individuals with the e4 allele (O’Shea et al., 2024). Cognitive reserve refers to the brain's ability to use its resources effectively to maintain normal cognitive function, even in the presence of age-related changes or disease.
Sleep
Improved sleep quality, including fewer nighttime awakenings, can reduce the impact of e4 on Alzheimer’s disease risk (Lim et al., 2013).
A Path Forward for Cognitive Health
Although genetics plays a role in Alzheimer’s risk, it’s the lifestyle choices we make that shape our cognitive future. By engaging in regular physical activity, cultivating social connections, practicing mindfulness, and ensuring restorative sleep, individuals can significantly improve brain health and resilience, regardless of their APOE status. Embracing these lifestyle practices offers a proactive approach to cognitive longevity, giving us the tools to support brain health and reduce the risks associated with genetic predispositions.
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