Hey crew, this week we're digging into a big question: can you really prevent Alzheimer's disease and the cognitive decline that comes with it? We'll walk through what the research actually says — the most important modifiable lifestyle factors, when to start building healthy habits, and what it all means for you.

No academic jargon… just the important research, gathered in one place.

So let's dive in.

Here's where things get interesting. A major report from the Lancet Commission on Dementia Prevention, Intervention, and Care reviewed decades of research from around the world to identify what actually influences our risk of developing Alzheimer's disease and related dementias.

The 2024 update highlighted 14 potentially modifiable risk factors across the lifespan and estimated that addressing them could prevent or delay up to 45% of dementia cases (Livingston et al., 2024).

That's a remarkable number. There's no guaranteed way to prevent dementia — but the research suggests that many of the habits supporting our overall health may also protect the brain over the long run.

So, despite what you might assume, brain health isn't determined by genetics alone. Many of the small choices we make throughout life add up over time, creating more chances to keep our brains healthy, resilient, and adaptable as we age.

🧠 Keep your brain engaged through education, learning, and mentally stimulating activities.

❤️ Protect your heart and vascular health by managing blood pressure, cholesterol, weight, and diabetes, and staying physically active.

👂👀 Take care of your senses by addressing hearing and vision loss when they arise.

🤝 Stay connected by maintaining meaningful relationships and reducing isolation.

🌱 Support your overall well-being by treating depression, avoiding smoking, limiting excessive alcohol, reducing head injuries, and minimizing exposure to air pollution.

Taken together, these factors paint a surprisingly encouraging picture: many of the things that are good for your body happen to be good for your brain, too.

We've all heard that the Mediterranean diet and solid sleep protect the brain — so why didn't they make the Lancet's list of established risk factors? It's not that they don't matter. The Commission looked at sleep, diet, infections, and mental health and concluded the evidence wasn't yet consistent enough to meet its bar for an established modifiable risk factor (Livingston et al., 2024).

That phrase "not yet consistent," is doing a lot of work, and it's worth unpacking, because it's a perfect example of why we read past the headlines.

Take sleep. The signal here is fairly strong: in a study following nearly 8,000 adults for 25 years, those who consistently slept six hours or less in midlife had roughly a 30% higher risk of developing dementia than those getting seven (Sabia et al., 2021). That's not proof short sleep causes dementia — but it's a hard pattern to ignore.

Diet is messier. Some studies link the Mediterranean and MIND diets to slower cognitive decline; others — including a large UK Biobank analysis of nearly 49,000 people — found surprisingly mixed, even counterintuitive results (UK Biobank diet analysis, 2021). Diet is genuinely hard to study: people misremember what they eat, and healthy eaters tend to do lots of other healthy things too. That messiness is exactly why diet is still labelled "emerging" rather than "established."

Here's the encouraging part. When researchers bundle these habits together and test them head-on, they hold up. Expanded models that fold in factors like diet and sleep estimate that an even larger share of dementia — in some populations more than 60% — could be preventable (Population attributable fractions review, 2024). And in the landmark FINGER trial, a two-year program combining diet, exercise, brain training, and vascular care helped at-risk older adults maintain and improve their cognition (Ngandu et al., 2015).

Takeaway: Just because a habit isn't on the official list doesn't mean it isn't working for you. Often it just means the science is still catching up to what your brain already appreciates.

You might be thinking: this is all great, but I'm only in my 30s — I've got plenty of time. You're partly right, but there's a catch: building these habits in early adulthood helps create resilience that pays off in later life.

Or maybe you're thinking the opposite: I'm already 60, so it's too late. Wrong again. Many intervention studies targeting these modifiable factors have shown cognitive improvements in adults over 65 — the FINGER trial being the clearest example, where a multidomain lifestyle program helped older adults preserve and even boost their cognition (Ngandu et al., 2015).

No matter your age or level of risk, starting to build these habits may be one of the most beneficial things you can do.

At this point you might be staring at that list of brain-healthy habits wondering how you're supposed to fit all of them into your life. Good news: you don't have to.

Research has identified many factors that support brain health, but there's no single "perfect" formula. We all have different priorities, schedules, interests, and abilities. The goal isn't to adopt every habit overnight, it's to find sustainable ones that fit your life.

For example, as a neuropsychologist in training and brain-health researcher, I prioritize regular physical activity, high-quality sleep, and keeping my brain engaged through learning and challenging activities. I try to follow many principles of the MIND diet by following an eating pattern linked to slower cognitive decline with age (Morris et al., 2015), while still enjoying life's occasional treats, and I stay as social as my social battery allows.

What works for me may not look exactly like what works for you and that's fine. If running isn't enjoyable or is tough on your joints, a daily walk may be a better fit; even regular walking has been shown to increase the size of the hippocampus, a key memory region, in older adults (Erickson et al., 2011). And if crosswords sound painfully boring, learning a genuinely new skill or diving into a topic you love works just as well. In one study, older adults who took up demanding new hobbies like photography or quilting saw real memory gains, while those doing familiar, low-effort activities did not (Park et al., 2014).

The most effective brain-health habits are the ones you can actually stick with. Small, sustainable changes made over time beat a perfect routine that lasts a week, and the behavioural science agrees: habits take a median of about two months of daily repetition to start feeling automatic, and missing the odd day doesn't break the streak (Lally et al., 2010).

Take a walk. Call a friend. Go to bed 30 minutes earlier. Read a chapter of a book. Schedule that hearing test you've been putting off.

The specific habit matters less than getting started.

Think of it as your first deposit into your brain's savings account. It may seem small today, but those deposits add up.