Use It or Lose It? What We Know About Preventing Dementia
I wanted to write about preventing dementia today.
But before starting to write this piece, I needed to make sure I hadn't already written about this very topic. Because apparently, remembering what I've written about is now part of my ongoing mini mental status exam.
The definition of dementia is a decline in memory, language, problem-solving and other thinking abilities that is severe enough to interfere with daily life.
I don't have dementia (at least as far as I know), but when I forget things like what I've already written about or can't remember the next thing I was supposed to say, it's hard not to wonder what the future holds.
So, can we prevent dementia? Or at least reduce our risk of developing it?
Let's break it down.
Nutrition
Let's start with food. Because, as it turns out, what we put in our mouths may affect more than just the number on the scale.
A 2025 systematic review and meta-analysis that included 23 studies found that following a Mediterranean diet was associated with an 11–30% lower risk of cognitive impairment, dementia and Alzheimer's disease.
The Mediterranean diet emphasizes fruits, vegetables, nuts, beans, whole grains and olive oil, along with fish, eggs, dairy and moderate amounts of meat. (And yes, red wine is traditionally included, although I'm not suggesting you start drinking wine for your brain. More on that later.)
And here's something interesting: A 2025 study published in Nature found that people carrying two copies of the APOE4 gene, a genetic risk factor associated with Alzheimer's disease, had a 35% lower risk of developing dementia if they closely followed a Mediterranean diet. Now, this was an observational study, so we can't say the there was a direct correlation. But it is encouraging that lifestyle changes can influence bad genes occasionally.
There are also studies suggesting that combining the Mediterranean diet with the DASH diet may offer additional cognitive benefits. The DASH diet (Dietary Approaches to Stop Hypertension) focuses on vegetables, fruits, whole grains, low-fat dairy, fish, poultry, beans and nuts. It emphasizes foods rich in potassium, calcium and magnesium while limiting sodium, added sugars and saturated fats.
What about supplements?
A 2022 meta-analysis suggested that dietary folate may be associated with slower cognitive decline. However, studies have not consistently shown that taking omega-3 supplements prevents dementia or treats existing dementia. Similarly, taking vitamins B6 and B12 has not consistently been shown to prevent or reverse cognitive decline in people who already have adequate levels.
The takeaway? Eat your vegetables. Save your money on most of the miracle brain supplements, unless you actually have a deficiency that needs treating.
Exercise
Well, here's some unfortunate news for those of us who have perfected the art of sitting.
A study involving 89,667 adults, with an average age of 63 and more than half women, found that every additional 30 minutes of moderate-to-vigorous physical activity per week was associated with a 4% reduction in the risk of all-cause dementia.
Yes, per week. And yes, even small amounts of additional activity were associated with benefits.
The CDC recommends at least 150 minutes of moderate-intensity physical activity each week.
Watching The Diplomat while working on this blog from the couch does NOT count. I checked.
Another study found that higher levels of physical activity during both midlife and later life were associated with a lower risk of all-cause dementia and Alzheimer's disease.
Darn.
That means the 50-year-old (in my mirror) watching an entire season of Carrie in a day isn't necessarily doing herself any favors.
The good news? You don't have to become a marathon runner. Walking, swimming, cycling, dancing and other activities that get your heart rate up all count. Now you (and I) just have to get up and do it!
Managing vascular risk factors
What does this mean? Simply put, preventing and adequately treating high blood pressure, diabetes and abnormal cholesterol.
Why? Because what's good for your heart and blood vessels is also good for your brain.
High blood pressure
Uncontrolled high blood pressure damages and stiffens blood vessels, including those supplying the brain. Over time, this can reduce blood flow and contribute to vascular damage.
A 2025 blood pressure guideline specifically recommends a systolic blood pressure goal below 130/80 mmHg for adults with hypertension to help prevent mild cognitive impairment and dementia, when appropriate for the individual.
Another reason not to ignore that blood pressure reading at your annual physical!
Diabetes
High blood sugar damages blood vessels and contributes to inflammation and other changes that can affect the brain.
A 2024 meta-analysis of 15 studies involving more than 10 million people found that individuals with diabetes had approximately a 59% higher risk of developing dementia compared with those without diabetes.
Interestingly, being diagnosed with type 2 diabetes at a younger age was associated with a greater risk of dementia later in life, particularly among people with obesity.
This is another reason why preventing diabetes when possible and managing it well when it develops are so important.
Cholesterol
Abnormal cholesterol levels, particularly elevated LDL (the cholesterol commonly referred to as "bad cholesterol"), contribute to plaque buildup and damage to blood vessels.
A 2024 Lancet Commission report identified high LDL cholesterol during midlife as an additional modifiable risk factor for dementia.
So, when I talk about managing cholesterol, I'm not just thinking about preventing heart attacks. I'm thinking about protecting the brain, too.
Depression
A study reported by Stanford researchers examined data from more than 246,000 people with depression and found that they had approximately 2.4 times the risk of developing dementia compared with people without a depression diagnosis.
Interestingly, the association remained even when depression had been diagnosed decades before dementia developed.
Does depression itself increase dementia risk? Could people with depression be less likely to engage in physical and social activities that protect cognitive health? Could there be underlying biological or genetic factors contributing to both conditions?
We don't have all the answers yet. And more studies are needed.
What we do know is that depression deserves to be taken seriously and treated. Mental health is health, and it shouldn't be something we put on the back burner.
Smoking
Is it okay if I simply say: DON'T SMOKE!
It's bad for you for approximately a thousand different reasons, and dementia risk is another one.
Smoking damages blood vessels, increases inflammation and contributes to cardiovascular disease, all of which can affect brain health.
If you smoke, quitting is one of the best things you can do for your overall health.
Alcohol
Ah, alcohol. This is where things get interesting.
A recent study involving more than 550,000 people examined alcohol consumption and dementia risk. The observational data initially suggested a U-shaped relationship, meaning that people who drank heavily and people who didn't drink at all appeared to have higher dementia risk than light drinkers.
So, does this mean we should all have a glass of wine a week to protect our brains?
Ummmmm. Things are a little more nuanced there.
When researchers used genetic analyses to investigate the relationship, they found that greater alcohol consumption was associated with increased dementia risk. But people in the early stages of dementia may drastically reduce their alcohol consumption before they are actually diagnosed. The apparent benefit of light drinking may partly reflect reverse causation so hard to say if light drinking is actually a good thing.
Alcohol can also contribute to brain injury, inflammation and changes in brain structure.
The bottom line? Don't start drinking for the supposed cognitive benefits. And if you drink, less is generally better when it comes to protecting your brain.
A few more things worth mentioning
I'm going to group these together, even though they really deserve their own paragraphs.
Research has identified several additional factors associated with dementia risk:
Hearing loss: Treating hearing loss, including using hearing aids when appropriate, may help reduce cognitive strain and maintain social engagement.
Vision loss: Correcting vision problems and getting regular eye care may also help protect cognitive health.
Head injuries: Wear your seatbelt, wear a helmet when appropriate, and take precautions to prevent traumatic brain injuries.
Air pollution: Exposure to air pollution is associated with increased dementia risk, likely through inflammation and vascular damage.
Education and social engagement: Education earlier in life and staying socially and mentally engaged throughout adulthood may help build and maintain cognitive reserve.
Social isolation: Staying in contact and engaging others helps build strong neural connections.
These factors were highlighted in the 2024 Lancet Commission report, which estimated that addressing 14 modifiable risk factors could potentially prevent or delay nearly 45% of dementia cases worldwide.
That's a pretty impressive number!
So, what does all this mean for preventing dementia?
Unfortunately, there is no magic pill, food, exercise routine or supplement that guarantees we won't develop dementia. Age and genetics still play a role, and even people who do everything "right" can develop it.
But there is encouraging news. Research increasingly suggests that a significant proportion of dementia cases may be delayed or prevented by addressing modifiable risk factors.
And here's what I take away from all of this: Most of the things that are good for our brains are also good for our hearts, our bodies and our overall health.
Eat reasonably well. Move your body. Keep your blood pressure, cholesterol and blood sugar under control. Don't smoke. Address depression. Take care of your hearing and vision. Take a walk before settling in for the next episode of the Diplomat.
Here's to taking care of our brains, one small decision at a time.
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