Brain health and dementia prevention: a practical guide with Dr. Tommy Wood

Executive overview

45–72% of dementia cases are estimated to be preventable through lifestyle. Most late-onset Alzheimer's is not genetically determined — it is driven by modifiable risk factors including sleep, physical activity, blood pressure, oral health, and cognitive stimulation.

The biggest lever is building brain reserve early and consistently: more capacity means more to lose before function degrades.

Why dementia is largely preventable

• The Lancet Commission estimates 45% of dementias are preventable; UK Biobank data suggests up to 72%
• Population attributable risk factors include hypertension, low physical activity, obesity, smoking, hearing loss, low early education, and alcohol
• Sleep deprivation and late-life physical inactivity are likely underrepresented in current estimates
• Late-onset Alzheimer's (95–99% of cases) is far more lifestyle-driven than early-onset genetic forms
• Individual risk cannot be guaranteed away, but odds can be shifted dramatically

The brain's energy problem — and why stimulation matters

• PET scans show less glucose uptake in Alzheimer's brains, but this reflects reduced activity, not inability to use glucose
• When stimulated cognitively, early Alzheimer's brains can take up glucose at normal rates
• The brain, like muscle, is demand-driven: use it or metabolic machinery atrophies
• Building energetic demand — not just supplying fuel — is key to long-term function
• Ketones and MCT oil can overcome the energetic deficit in early Alzheimer's, but are not necessarily required for prevention in healthy people

Exercise: type and intensity both matter

• Open-skill exercise (dancing, martial arts, ball sports, rock climbing) shows the largest effect sizes for brain health — these require reacting to an unpredictable environment
• Dance has the highest effect size of any single physical activity for dementia prevention and mental health
• Closed-skill aerobic exercise (running, cycling) benefits are intensity-dependent: producing lactate drives BDNF production in the brain
• The Norwegian 4×4 protocol (4 min at 85–95% max heart rate × 4 sets) showed durable hippocampal improvements maintained for 5 years post-trial
• Lactate — not muscle-derived BDNF — is the primary driver of brain-derived BDNF via histone deacetylase inhibition; ketones and osteocalcin have similar effects
• Blood flow restriction (BFR) training generates significant lactate at low load; useful for travel or injury recovery
• Walking 4,000+ steps/day reduces dementia risk; 10,000 steps is associated with hippocampal volume increases

Nutrition and key supplements

• Omega-3s (DHA/EPA): 1–2 g DHA/day from oily fish or supplement; DHA concentrates at synapses and in mitochondria; protects against sub-concussive brain injury accumulation
• B vitamins (B12, folate/B9, riboflavin/B2, B6): required alongside omega-3s — neither works alone for dementia prevention; target: normalise homocysteine below ~13
• DHA and B vitamins are synergistic: DHA must be phospholipid-attached via methylation to function in cell membranes
• Creatine: 10 g/day (take in morning — can be cognitively stimulating); benefits seen in depression, sleep deprivation, and TBI recovery; use CreaPure monohydrate
• CDP-choline (citicoline): 500–1,000 mg/day shown to improve cognitive function in decline and after TBI; most people can get choline from eggs, liver, sardines, oats
• Vitamin D (supplement in winter), magnesium, and iron (especially women) are foundational
• Polyphenols from berries, coffee, tea, and roasted nuts/seeds show consistent cognitive benefits
• Xylitol gum or mouthwash reduces cavity- and periodontitis-causing bacteria (Strep mutans, P. gingivalis)

Acute brain injury: what to do immediately

• Prevent fever (antipyretics, acetaminophen) — hyperthermia widens the gap between metabolic demand and impaired mitochondrial supply
• Avoid refined carbohydrates — high glucose spikes worsen acute injury
• Creatine and omega-3s (especially if already on board) support recovery
• Exogenous ketones: not yet in published protocols, but plausible given mechanistic evidence
• Riboflavin, branched-chain amino acids, and melatonin (if sleep disrupted) have supporting evidence
• Avoid caffeine early post-injury — increases metabolic rate similarly to fever
• Early return to low-level aerobic exercise (below symptom threshold) is one of the strongest evidence-based interventions; mechanism likely includes improved cerebral blood flow, myokines, and sleep

Cognitive stimulation and creative skills

• Complex multi-sensory skills — tango, language learning, music, video games, visual art — improve the discreteness of brain networks that degrade with ageing (measured via EEG "brain clocks")
• Bilingualism improves executive function (response inhibition) and delays dementia onset; benefits seen even with app-based language learning (Duolingo) in older adults
• Error and failure drive neuroplasticity: you must exceed current capacity (like training to failure) for adaptation to occur
• Many "brain training" apps fail because they don't create meaningful failure or transfer to real cognitive tasks
• Super Mario 3D World has the strongest published evidence of any video game for cognitive function

Sensory health, sleep, and other modifiable risks

• Hearing aids and cataract surgery reverse the dementia risk associated with age-related sensory loss; loss of engagement with the world — not the sensory loss itself — drives decline
• Sleep is the non-negotiable: poor sleep accelerates amyloid accumulation; improving sleep at any age reduces burden
• Short-term sleep deprivation slows processing speed but not accuracy; mood is affected more than performance
• Catastrophising about poor sleep worsens outcomes; self-induced anxiety about sleep is a real effect
• DORAs (dual orexin receptor antagonists, e.g. suvorexant) are now the best pharmacological option for sleep when CBT-I fails; sleep improvement likely helps via glymphatic clearance
• Air quality: fine particulate matter (wildfire smoke, traffic) raises blood pressure and dementia risk; HEPA filters (Jaspr, Blueair, Coway Airmega) mitigate indoor exposure
• High CO2 from poor ventilation disrupts sleep — keep a window open
• Oral health: gum disease (periodontitis) bacteria are found in both atherosclerotic and amyloid plaques; regular dental care is a meaningful dementia risk factor
• High blood sugar and high blood pressure are the two most important metabolic risk factors for dementia; managing both is critical
• Avoid excessive alcohol; do not smoke