Understanding risk factors: modifiable vs. non-modifiable

Non-modifiable factors: accepting what cannot be changed

Before exploring what we can act on, let's first recognize what is beyond our control:

Age: the main factor

• The risk increases exponentially after 65 years
• At 65: 2% risk
• At 75: 10% risk
• At 85: 30% risk
• But aging is NOT a guarantee of Alzheimer's

Biological sex

• Women have 1.5 times more risk
• Possibly linked to menopause and the drop in estrogen
• Longer life expectancy also plays a role
• Research on hormone therapy continues

Genetics

• APOE4 gene: present in 20-25% of the population
  • One copy = risk x3
  • Two copies = risk x12
• Rare familial mutations (APP, PS1, PS2): less than 1% of cases
• Having these genes is NOT a sentence: many carriers never develop the disease

Testimonial of hope: "I have two copies of APOE4. Instead of giving up, I focused on modifiable factors. At 72, my cognition is excellent. Genes load the gun, but it's our lifestyle that pulls the trigger." - Dr. Richard Isaacson, neurologist and patient.

Modifiable factors: our power to act

The 14 modifiable factors identified by the Lancet Commission 2024 together represent 45% of the risk. Each factor contributes differently:

1. Low educational level (7%)
2. Hearing impairment (7%)
3. Hypertension (5%)
4. Smoking (5%)
5. Obesity (3%)
6. Depression (3%)
7. Physical inactivity (3%)
8. Diabetes (3%)
9. Excessive alcohol consumption (3%)
10. Head trauma (2%)
11. Air pollution (2%)
12. Social isolation (2%)
13. Visual impairment (2%)
14. High LDL cholesterol levels (1%)

These percentages add up and interact, creating a powerful cumulative effect.

Physical activity: the miracle drug that does not exist in pill form

The spectacular impact of exercise on the brain

Physical exercise is probably the most powerful intervention to prevent Alzheimer's. Studies show a 30 to 45% risk reduction in active people.

What happens in your brain when you move:

1. Stimulated neurogenesis Exercise increases the production of BDNF (Brain-Derived Neurotrophic Factor), nicknamed "brain fertilizer." BDNF:

• Stimulates the creation of new neurons in the hippocampus
• Strengthens existing synaptic connections
• Protects neurons against oxidative stress
• Improves brain plasticity

Remarkable fact: A single exercise session increases BDNF by 20-30% for several hours.

2. Improved brain circulation

• Increase in blood flow of 15-20%
• Better oxygenation of brain tissues
• More efficient elimination of metabolic waste
• Formation of new blood vessels (angiogenesis)

3. Inflammation reduction Regular exercise:

• Decreases inflammatory markers (CRP, IL-6)
• Activates anti-inflammatory cells
• Reduces excessive microglial activation
• Protects the blood-brain barrier

4. Improved glymphatic system This brain "cleaning" system, particularly active at night, is optimized by exercise:

• Better elimination of beta-amyloid proteins
• Increased clearance of tau protein
• Reduced pathological deposits

Types of exercise and their specific benefits

Aerobic exercise (the champion)

• What: Brisk walking, jogging, swimming, cycling, dancing
• Optimal dose: 150 minutes/week of moderate intensity OR 75 minutes of vigorous intensity
• Specific benefits:
  • Increases hippocampus volume by 2% per year (vs. 1-2% loss without exercise)
  • Improves episodic memory
  • Reduces cognitive decline by 30-40%

Notable study: Erickson's study (2011) showed that one year of brisk walking (40 min, 3x/week) increased hippocampal volume in seniors aged 65 and over.

Resistance training (the complementary)

• What: Weights, bands, bodyweight exercises
• Optimal dose: 2-3 sessions/week
• Specific benefits:
  • Improves executive functions
  • Reduces homocysteine (vascular risk factor)
  • Maintains muscle mass (fall prevention)
  • Improves insulin sensitivity

Balance and coordination exercises

• What: Tai chi, yoga, dancing
• Optimal dose: 2-3 sessions/week
• Specific benefits:
  • Stimulates the cerebellum and basal ganglia
  • Reduces risk of falls and head trauma
  • Improves proprioception
  • Additional meditative effect

HIIT (High-Intensity Interval Training)

• What: Alternating intense efforts/recovery
• Optimal dose: 1-2 sessions/week of 20-30 minutes
• Specific benefits:
  • Rapid increase in BDNF
  • Improvement in metabolic flexibility
  • Cognitive gains in less time
  • Stimulation of cellular autophagy

Practical program for beginners

Week 1-4: Building the habit

• Monday: 15 min moderate walk
• Wednesday: 15 min walk + 5 min stretching
• Friday: 20 min moderate walk
• Weekend: A enjoyable activity (gardening, walking)

Week 5-8: Progressive increase

• Monday: 25 min brisk walk
• Tuesday: 15 min light resistance exercises
• Thursday: 25 min brisk walk
• Saturday: 30 min activity of choice
• Sunday: Yoga or tai chi 20 min

Week 9-12: Established routine

• 150 min/week of moderate activity spread out
• 2 strengthening sessions
• 1-2 balance sessions
• Variation of activities to maintain motivation

Advice from a senior specialized coach: "The secret is not intensity but regularity. Better 15 minutes every day than 2h once a week. The brain loves consistency."

Overcoming obstacles

"I don't have time"

• Divide: 3x10 min = 30 min
• Integrate into daily life: stairs, walk for shopping
• Wake up 20 min earlier
• Active lunch break

"I have joint issues"

• Swimming or aquagym (water buoyancy)
• Exercise bike
• Seated exercises
• Physical therapist consultation for adapted program

"I don't like sports"

• Dance (social and cognitive)
• Gardening (400 cal/hour)
• Photographic walks
• Active games with grandchildren
• Shopping centers in bad weather

Diet: nourishing your brain to protect it

The MIND Diet: the winning fusion

The MIND diet (Mediterranean-DASH Intervention for Neurodegenerative Delay) combines the best of the Mediterranean diet and the DASH diet. Studies show a 53% reduction in Alzheimer's risk among strict adherents and 35% among moderate adherents.

The 10 protective foods to favor:

1. Leafy green vegetables (6+ servings/week)

• Spinach, kale, arugula, Swiss chard
• Rich in vitamin K, lutein, folates, beta-carotene
• Protection against cognitive decline of 11 years younger

2. Other vegetables (1+ serving/day)

• Priority to colorful ones: broccoli, bell peppers, carrots
• Various antioxidants
• Fiber for the microbiota

3. Berries (2+ servings/week)

• Blueberries champions: neuroprotective anthocyanins
• Strawberries, raspberries, blackberries
• Fresh or frozen (nutrients preserved)

4. Nuts (5+ servings/week)

• Walnuts: plant-based omega-3s
• Almonds: vitamin E
• A handful = one serving

5. Olive oil (main daily use)

• Extra virgin only
• Anti-inflammatory polyphenols
• Replacement for butter and other oils

6. Whole grains (3+ servings/day)

• Oats, quinoa, brown rice
• Fiber and B vitamins
• Low glycemic index

7. Fatty fish (1+ serving/week)

• Salmon, mackerel, sardines
• Essential omega-3 DHA for the brain
• Avoid large predators (mercury)

8. Legumes (3+ servings/week)

• Lentils, beans, chickpeas
• Plant-based proteins and fiber
• Glycemic regulation

9. Poultry (2+ servings/week)

• Chicken, turkey
• Lean proteins
• Source of B vitamins

10. Red wine (1 glass/day maximum, optional)

• Protective resveratrol
• BUT risks if excess
• Can be replaced by red grapes

The 5 foods to limit:

1. Red meat (< 4 servings/week)
2. Butter/margarine (< 1 tablespoon/day)
3. Cheese (< 1 serving/week)
4. Pastries and sweets (< 5 servings/week)
5. Fried/fast food (< 1 serving/week)

Key nutrients for the brain

Omega-3 (DHA and EPA)

• Role: Structural components of neuronal membranes
• Sources: Fatty fish, algae, nuts
• Dosage: 250-500mg DHA/day
• Supplementation: If vegetarian or low fish consumption

Antioxidants (vitamins C, E, carotenoids)

• Role: Neutralization of free radicals
• Sources: Colorful fruits, vegetables, nuts
• Synergy: More effective together than isolated

Vitamins B (B6, B12, folates)

• Role: Reduction of homocysteine
• Risk: Frequent B12 deficiency after 60 years
• Test: Annual dosage recommended

Vitamin D

• Role: Neuroprotection, anti-inflammation
• Deficiency: 80% of seniors in winter
• Dosage: 1000-2000 IU/day according to blood level

Practical meal plan for a week

Monday

• Breakfast: Oat flakes + blueberries + walnuts + cinnamon
• Lunch: Spinach salad + grilled salmon + olive oil vinaigrette
• Dinner: Roasted chicken + steamed broccoli + quinoa
• Snack: Apple + almonds

Tuesday

• Breakfast: Green smoothie (spinach + banana + berries + flax seeds)
• Lunch: Lentil soup + whole grain bread + green salad
• Dinner: White fish + ratatouille + brown rice
• Snack: Plain yogurt + nuts

Wednesday

• Breakfast: Scrambled eggs + avocado toast + tomatoes
• Lunch: Buddha bowl (quinoa + chickpeas + colorful vegetables)
• Dinner: Turkey + green beans + sweet potato
• Snack: Mixed berries

[Continue with Thursday-Sunday...]

Pitfalls to avoid

Sugar: the silent enemy

• Glycation of brain proteins
• Chronic inflammation
• Cerebral insulin resistance ("type 3 diabetes")
• Limit: < 25g added sugars/day

Trans fats

• Increase risk by 75%
• Sources: industrial products, reused frying
• Read labels: "partially hydrogenated oils"

Excess salt

• Hypertension = major risk factor
• Limit: < 5g/day
• 80% of salt comes from processed products

Testimonial from Marie, 68 years old: "Adopt the MIND diet has transformed my life. In 6 months, I lost 8 kg, my tension has dropped, and above all, I feel mentally sharper. Cognitive tests confirm it: 15% improvement in my working memory."

Sleep: the brain's nightly cleaning system

The revolutionary discovery of the glymphatic system

In 2013, a discovery revolutionized our understanding of sleep: the glymphatic system, a true "dishwasher" of the brain, is 10 times more active during deep sleep.

How it works:

1. Brain cells shrink by 60% during sleep
2. Intercellular spaces enlarge
3. Cerebrospinal fluid circulates massively
4. Metabolic waste is cleared, including beta-amyloid
5. The process is optimal in the lateral position

Alarming fact: A single night of sleep deprivation increases brain amyloid by 5%. Imagine the effect of decades of chronic insomnia.

Sleep stages and their importance

Deep sleep (stages 3-4 NREM)

• 15-20% of the night
• Consolidation of declarative memory
• Maximum activation of the glymphatic system
• Growth hormone production
• Decreases with age (50% loss at 60 years)

REM sleep

• 20-25% of the night
• Consolidation of emotional and procedural memory
• Creativity and problem-solving
• Emotional regulation

Optimal architecture:

• 7-9 hours for adults
• 4-6 complete cycles of 90 minutes
• Regularity more important than quantity

Sleep disorders: major risk factors

Sleep apnea

• Multiplies Alzheimer's risk by 2-3
• 30-40% of those over 65 affected
• Repeated cerebral hypoxia
• Test: polysomnography if snoring + fatigue

Chronic insomnia

• Increases risk by 40%
• Inflammatory activation
• Associated chronic stress
• Treatment: CBT-I more effective than sleeping pills

Sleep fragmentation

• Frequent awakenings = incomplete cleaning
• Causes: nocturia, pain, anxiety
• Solutions: treat underlying causes

Strategies to optimize sleep

Fundamental sleep hygiene

Regular schedules

• Fixed bedtime and wake-up ± 30 min
• Weekend included
• Nap limited to 20 min before 3 pm

Optimal environment

• Temperature: 18-20°C
• Total darkness (mask if necessary)
• Silence or white noise
• Quality mattress and pillows
• Preferred lateral position

Evening routine (90 min before bedtime)

• 9 pm: Stop screens
• 9:15 pm: Warm shower
• 9:30 pm: Calm activity (reading, meditation)
• 10 pm: Bedroom, dim light
• 10:30 pm: Lights out

Strategic light exposure

• Morning: 30 min bright light (10,000 lux)
• Day: maximize natural light
• Evening: warm, dim lights
• Night: total darkness

Nutrition and sleep

To favor:

• Tryptophan: turkey, banana, milk (serotonin/melatonin precursor)
• Magnesium: green vegetables, nuts (muscle relaxation)
• Tart cherry: natural melatonin
• Herbal teas: chamomile, valerian, passionflower

To avoid:

• Caffeine after 2 pm (half-life 6h)
• Alcohol (fragments sleep)
• Heavy meals < 3h before bedtime
• Excessive liquids in the evening

Technologies and sleep aids

Useful applications:

• Sleep Cycle: phase analysis
• Headspace: sleep meditations
• Noisli: white noises

Devices:

• Dawn simulator lamps
• Sleep trackers
• White noise machines
• Connected mattresses

Supplements (upon medical advice):

• Melatonin: 0.5-3mg, 2h before bedtime
• Magnesium glycinate: 200-400mg
• L-theanine: 100-200mg
• Ashwagandha: 300-600mg

Testimonial from Paul, 72 years old: "I ignored my sleep apnea for 10 years. After CPAP treatment, my wife says I'm 'back.' My memory improved by 30% in tests. Sleep is truly the foundation of brain health."

Cognitive stimulation: training your brain

The concept of cognitive reserve

Cognitive reserve is the brain's ability to compensate for damage by using alternative networks. The higher it is, the more the brain resists pathologies.

What builds the reserve:

• Formal education
• Continuous learning
• Complex intellectual activities
• Bilingualism/multilingualism
• Rich social interactions
• Stimulating career

Striking study: Nun Study's nuns with high education showed few symptoms despite brains ravaged by Alzheimer's upon autopsy.

Protective cognitive activities

Learning new skills

• Foreign language: Risk reduction by 40-50%
  • Applications: Duolingo, Babbel
  • Group courses: bonus socialization
  • Daily practice 15-30 min
• Musical instrument: Multi-zone stimulation
  • Coordination, memory, creativity
  • Piano, guitar accessible to seniors
  • Adapted online courses
• Digital skills: Continuous adaptation
  • Digital photography
  • Online genealogy
  • Content creation

Daily intellectual activities

Active reading

• Complex novels > magazines
• Book clubs: stimulating discussion
• Various genres: neuroplasticity
• 30 min/day minimum

Writing

• Personal journal: autobiographical memory
• Correspondence: social bond
• Creation: novels, poetry
• Blog: sharing and feedback

Effective brain games

• Crosswords/Sudoku: maintaining skills
• Chess/Bridge: complex strategy
• Puzzles 1000+ pieces: visuospatial
• Adapted video games: multi-task coordination

Structured stimulation program

Typical weekly program:

Monday: Language

• Morning: Crosswords (20 min)
• Afternoon: Reading novel (45 min)
• Evening: Family Scrabble

Tuesday: Memory

• Morning: Poem memorization
• Afternoon: Card game (Memory)
• Evening: Photo album review with story

Wednesday: Executive functions

• Morning: Week planning
• Afternoon: Cooking new recipe
• Evening: Chess game

Thursday: Creativity

• Morning: Journal writing
• Afternoon: Painting/drawing
• Evening: Music

Friday: Social-cognitive

• Morning: Volunteering
• Afternoon: Club/association
• Evening: Board games with friends

Weekend: Varied activities

• Cultural outings
• Creative projects
• Free learning

The EDITH program: adapted cognitive stimulation

EDITH offers 30+ games specifically designed for prevention:

• Automatic adaptation to level
• Progress tracking
• Scientifically validated exercises
• Senior-friendly interface
• Prevention mode and therapeutic mode

Observed results:

• Improved working memory: 20%
• Processing speed: +15%
• Cognitive flexibility: +25%
• Maintenance of gains over 2 years

Social factors: the power of human connections

Social isolation: a poison for the brain

Social isolation increases Alzheimer's risk by 40%, equivalent to smoking.

Harmful mechanisms:

• Increased chronic inflammation
• Elevated cortisol (chronic stress)
• Reduced cognitive stimulation
• Frequent secondary depression
• Neglect of health

Alarming figures:

• 25% of those over 65 socially isolated
• 43% feel lonely regularly
• COVID worsened by 30%

Strategies to maintain connections

Structured social activities

Volunteering

• Purpose and usefulness
• Regular contacts
• Cognitive stimulation
• 2h/week = 40% risk reduction

Clubs and associations

• Shared interest centers
• Regular meetups
• Common projects
• New friendships

Intergenerational activities

• School support
• Transfer of know-how
• Childcare for grandchildren
• Invigorating energy

Connection technologies

• Video calls with distant family
• Senior social networks
• Thematic forums
• Collective online courses

Inspiring initiative: "Les Talents d'Alphonse" connects senior experts and companies for temporary missions. Valorization + social connection + cognitive stimulation.

Cardiovascular risk factors: what's good for the heart is good for the brain

Hypertension: the silent killer

Midlife hypertension increases Alzheimer's risk by 60%.

Destructive mechanisms:

• Cerebral microhemorrhages
• Chronic hypoperfusion
• Blood-brain barrier alteration
• Leukoaraiosis (white matter lesions)

Blood pressure goals:

• < 130/80 mmHg