Watching a family member lose their memory, identity, and autonomy can leave a deep mark. For this reason, we naturally develop a fear of the possibility that it might happen to us, too. However, genetically determined Alzheimer’s accounts for less than 1% of all cases. For the remaining 99%, lifestyle habits matter more than genes.
How hereditary is Alzheimer’s?
Within Alzheimer’s, there are two distinct realities:
- Familial Alzheimer’s: This is the only type of Alzheimer’s that is inherited in a direct and predictable way. It is caused by mutations in one of these three genes: APP, PSEN1, and PSEN2. When a person has one of these mutations, each child has a 50% chance of inheriting it. In this case, symptoms usually appear before age 60, sometimes even in one’s 40s. Fortunately, this accounts for less than 1% of cases.
- Sporadic or late-onset Alzheimer’s: Here, genetics influence the risk but do not determine the outcome. The best-known genetic factor is the APOE gene. Each person inherits two copies of the APOE gene (one from the father and one from the mother). One of its variants, called APOE ε4, is associated with a higher risk of developing Alzheimer’s. Having one copy can increase the risk, and having two can increase it even further. However, not everyone with this variant develops Alzheimer’s, and many Alzheimer’s patients do not have this variant.
Genetics can also influence things for the better, as there are protective variants of this gene that represent a lower risk of developing the disease.
How to prevent Alzheimer’s: 14 modifiable factors
The 2024 Lancet Commission, the most up-to-date scientific reference on dementia prevention, estimates that nearly half of dementia cases worldwide could be prevented or delayed by addressing 14 modifiable risk factors. We have organized them by life stage:
Youth (under 45 years old)
- Lower level of education
Midlife (45-65 years old)
- Untreated hearing loss
- Smoking
- Depression
- Hypertension
- Obesity
- Diabetes
- Excessive alcohol consumption
- High LDL cholesterol
Later life (over 65 years old):
- Social isolation
- Physical inactivity
- Untreated vision loss
- Head injuries
- Air pollution
How to prevent Alzheimer’s: habits with the strongest scientific evidence
Although there is no guaranteed way to prevent Alzheimer’s, we do know that some habits are associated with a lower risk of cognitive decline and dementia.
- Mediterranean diet: This is one of the most studied dietary patterns in brain health. A meta-analysis of 23 studies observed that high adherence to the Mediterranean diet was associated with an 18% reduction in the risk of mild cognitive impairment, an 11% reduction in the risk of dementia, and a 30% reduction in the risk of Alzheimer’s. We are talking about a diet rich in vegetables, fruits, legumes, nuts, extra virgin olive oil, fish, and whole grains, with a lower presence of ultra-processed foods, sugars, and poor-quality fats.
- Physical exercise: By moving your body, you are also taking care of your brain. Physical activity helps improve cardiovascular health, promotes cerebral blood flow, contributes to reducing inflammation, and can strengthen what is known as cognitive reserve—that is, the brain’s ability to better resist changes associated with age or disease. You don’t need to start with big challenges: walking at a brisk pace, doing adapted strength exercises, or staying active regularly can already make a difference.
- Cognitive stimulation and social life: Learning new things, reading, playing an instrument, dancing, doing crafts, participating in cultural activities, or maintaining active conversations and social bonds also add up. These activities will not “shield” the brain, but they help keep it trained and connected. Undesired loneliness and isolation, on the other hand, have been linked to poorer cognitive health, so taking care of your social life is also part of brain care.
- Control of blood pressure, cholesterol, and diabetes. Brain health is closely linked to vascular and metabolic health. For this reason, controlling hypertension, cholesterol, insulin resistance, or diabetes is a primary intervention, especially after age 40 or 50. What protects the heart often also protects the brain.
Above all, science points out that the greatest benefit appears when several strategies are combined. The PENSA study, developed by the Barcelonaβeta Brain Research Center, observed that combining a healthy diet, physical exercise, cognitive training, and a green tea extract rich in EGCG could improve cognition up to 4.5 times more and reduce the risk of dementia by 25% in people carrying the APOE ε4 variant. This type of study reminds us that, like everything else, it is not about looking for a single miracle solution, but about acting on several fronts at the same time.
