Every year, stroke, dementia, and depression affect millions of people — but many of the risks are within our control. A major new study shows that the same simple habits can protect you from all three conditions at once. Here’s what the research found, and how you can start making changes today.

Recent research has identified 17 overlapping factors that affect your risk of stroke, dementia and late-life depression, suggesting that several lifestyle changes could simultaneously lower the risk of all three conditions.

Though they may seem unconnected, people who experience one of these brain conditions often develop one or both of the others as well.

This is because they may share underlying damage to small blood vessels in the brain, according to Dr Sanjula Singh, principal investigator at the Brain Care Labs at Massachusetts General Hospital and lead author of the study.

The research suggests that at least 60% of strokes, 40% of dementia cases and 35% of late-life depression cases could be prevented or slowed by controlling risk factors.

"Those are striking numbers," notes Dr Stephanie Collier, director of education in the division of geriatric psychiatry at McLean Hospital. "If you can really optimise the lifestyle pieces or the modifiable pieces, then you're at such a higher likelihood of living life without disability."

Note: While the study was conducted in the US, the findings are relevant globally and align closely with NHS health recommendations in the UK.

Protective Factors That Lower Your Risk

1. Low to Moderate Alcohol Intake

Consuming less than one drink per day showed the most benefit. Even one to three drinks per day provided some protection compared to higher consumption.

NHS Guidance: Drink no more than 14 units of alcohol per week, spread over at least three days.

2. Regular Cognitive Activity

Engaging in mentally stimulating tasks like reading, doing puzzles, or learning new skills appears to have a significant protective effect, reducing dementia risk by about 40%.

3. Nutritious Diet

A diet rich in vegetables, fruit, whole grains, fish, low-fat dairy, and nuts was associated with lower risk of all three conditions.

4. Physical Activity

Moderate to high levels of physical activity significantly reduced the likelihood of stroke and dementia.

NHS Guidelines: Aim for at least 150 minutes of moderate-intensity activity weekly, such as brisk walking, cycling, or gardening.

5. Purpose in Life

Having a sense of meaning and direction in life showed a protective effect against cognitive decline and depression.

6. Strong Social Connections

Maintaining a wide social network and staying socially engaged was linked to better brain health outcomes.

Risk Factors That Increase Your Likelihood

The research also identified 13 distinct factors that raise your risk of developing stroke, dementia or late-life depression.  Combined with the 6 protective factors listed above, researchers have identified a total of 17 key elements that influence brain health.

Note that diet and social connections appear in both categories—they protect your brain when strong but increase risk when poor.

1. High Blood Pressure – Nearly triples the risk of stroke.

   
   

2. High Body Mass Index (BMI) – Excess weight significantly increases risk.

   
   

3. High Blood Sugar – Even pre-diabetic blood sugar levels raise risk.

   
   

4. High Total Cholesterol– Contributes to cardiovascular issues affecting the brain.

   
   

5. Depressive Symptoms – Even mild depression increases risk.

   
   

6. Poor Diet – High intake of red meat, sugary drinks, sweets and salt raises risk.

   
   

7. Hearing Loss – Untreated hearing problems are linked to dementia.

   
   

8. Kidney Disease – Associated with higher risk of all three conditions.

   
   

9. Chronic Pain – Especially when it interferes with activity.

   
   

10. Sleep Disturbances – Poor sleep, insomnia, or regularly sleeping over 8 hours.

    
    

11. Smoking History – Current or past smoking increases risk.

    
    

12. Loneliness or Social Isolation – Limited contact and feelings of loneliness raise vulnerability.

    
    

13. Stress – Both chronic stress and stressful life events are contributing factors.

Where to Begin Making Changes

Addressing all 17 factors at once can feel overwhelming. Dr Singh recommends approaching it like a menu: “Choose just one risk factor and then take it step by step.”

Start with Blood Pressure

High blood pressure emerged as the most significant individual risk factor. A separate study published in Nature Medicine found that patients who successfully reduced their blood pressure were 15% less likely to develop dementia.

To lower blood pressure:

• Reduce salt intake

• Increase physical activity

• Lose weight, if appropriate

• Consider medication if lifestyle changes alone aren’t enough

Speak to your GP or practice nurse if you’re unsure about your blood pressure or need support managing it.

Combine Physical, Mental and Social Activities

Some activities combine multiple protective factors and are especially effective. For example:

• Join a walking group – combines physical activity and social connection

• Take a class to learn a new skill – combines cognitive activity and social interaction

• Volunteer for a cause you care about – builds purpose, connection and often includes movement

Dr Collier recommends tasks that are “a little bit difficult” and ideally done with others, as conversation can boost cognitive stimulation and reduce feelings of isolation.

Start Early – But It’s Never Too Late

The best time to begin making these lifestyle changes is in middle age, before any symptoms appear. But don’t worry if you’re starting later – research shows that these changes can still slow disease progression and improve quality of life even in older age.

Even for those with a genetic predisposition to these conditions, lifestyle modifications can make a significant difference. As Dr Singh points out, “It’s not your inevitable fate. There are things we all can do to take better care of our brains.”

Small changes add up. By focusing on just a few key areas — like staying active, eating well, and staying connected — you can strengthen your brain health now and in the future. The earlier you start, the bigger the difference it can make.