The Psychology of Fighting Dementia | Dr Tommy Wood
Dr. Tommy Wood discusses how approximately 45% of dementia cases could be prevented through modifiable lifestyle factors, challenging the conventional belief that cognitive decline is inevitable. He presents a three-part model (Stimulus, Supply, Support) for maintaining brain health across the lifespan, supported by evidence that age-specific dementia incidence has actually been decreasing in recent decades.
Summary
Dr. Tommy Wood, physician and neuroscientist at the University of Washington, discusses the psychology and prevention of dementia with host Dr. Michael Gervais. Currently, 7-8 million people in the US and 56-64 million worldwide live with dementia, with burden expected to double or triple in the next two decades. However, research indicates that 45% of dementia cases could be completely prevented, with some analyses suggesting prevention rates as high as 70%.
Wood challenges the historical assumption that cognitive decline is inevitable after a certain age, tracing this belief back to neuroscientist Santiago Ramón y Cajal's 1906 claim that the adult brain is "immutable," and physician William Osler's early 20th-century assertion that people over 60 were "useless." The Seattle Longitudinal Study demonstrated that over 50% of people maintain cognitive function from their 50s into their 70s and beyond, contradicting prevailing expectations. Importantly, age-specific incidence of dementia has been decreasing for several decades, suggesting population-level interventions targeting cardiovascular disease have had spillover benefits for brain health.
Wood presents a systems-thinking model organized around three interconnected "Ss": Stimulus, Supply, and Support. Stimulus refers to cognitive engagement—education, complex skill learning, new hobbies, and social engagement—which functions as the primary driver of brain function, analogous to physical training for muscles. Supply encompasses blood flow to the brain and energy availability, including metabolic health (blood pressure, blood sugar regulation) and specific nutrients like omega-3 fatty acids, B vitamins, vitamin D, and iron. Support includes the recovery and adaptation period, primarily through sleep, as well as avoiding factors that impair adaptation such as smoking, excessive alcohol, chronic stress, air pollution, and dental disease.
The 14 modifiable risk factors identified by the Lancet Commission on Dementia Prevention include cardiovascular disease risk, diabetes, obesity, physical inactivity, smoking, excessive alcohol, cognitive inactivity, depression, social isolation, hearing loss, vision loss, head injury, air pollution, and low education. Wood emphasizes that socioeconomic status significantly determines access to these interventions, suggesting that meaningful population-level change requires societal intervention, not just individual responsibility.
Regarding genetics, Wood explains that APOE4 genotype—the most common genetic risk factor for Alzheimer's disease—functions as a risk multiplier rather than a guaranteed pathway to dementia. Those with APOE4 show larger increases in risk with poor lifestyle choices but also potentially larger benefits from addressing modifiable factors. Importantly, there are populations where APOE4 does not increase dementia risk, suggesting gene-environment interactions are modifiable.
On measurement and implementation, Wood recommends testing for specific biomarkers: blood pressure and blood sugar (most closely tied to dementia risk), vitamin D levels (targeting at least 30, ideally 40-60 ng/mL), homocysteine levels (ideally below 10-11 μmol/L), omega-3 index (targeting above 5%, ideally 6-8%), and iron status (hemoglobin above 12.5 in women, 13.5 in men). He notes that the COSMOS trial found benefit from basic multivitamins, and creatine shows promise for cognitive function in specific populations including older adults, those with brain trauma, and those experiencing sleep deprivation.
Wood addresses the concept of subjective cognitive decline—when individuals notice changes in their cognition before meeting diagnostic criteria for mild cognitive impairment or dementia. He emphasizes that this period is largely reversible through interventions addressing the 3S model. Multiple trials demonstrate significant improvements in cognitive function through lifestyle changes even in later life. He emphasizes starting with one modifiable factor rather than attempting all changes simultaneously, as even incremental improvements in one area can generate positive cascading effects across the system.
Wood presents a causal framework for understanding dementia not as inevitable but as a systems outcome of multiple interacting factors, and notes that the field has historically focused too narrowly on protein accumulation (amyloid, tau) in the brain while neglecting inflammation, vascular changes, and lifestyle factors that influence these processes.
About this episode
<p><strong>What are the things we can do today to help minimize our chances of developing dementia as we age?</strong></p><p><strong>Dr. Tommy Wood</strong> is a physician and neuroscientist, Associate Professor of Pediatrics and Neuroscience at the University of Washington, and author of <em>The Stimulated Mind</em>.</p><p>The book takes on a belief many of us still hold, that the adult brain becomes fixed at an early age and then declines from there. Tommy traces that idea back to 1906 and to the words of a Nobel laureate. Then he unpacks what the latest research and data say, and it’s not what you might think.</p><p>This is a conversation about a tough subject, mental decline and dementia. Many of us have been touched by this in our own families, and what Tommy has to say gives all of us hope that we have more agency than we think when it comes to this part of our health.</p><p>Tommy and Mike get into the 14 modifiable risk factors named by the Lancet Commission, why midlife is when risk starts to diverge, and the three buckets Tommy sorts everything into: stimulus, supply, and support. Mike talks about his grandfather, who had vascular dementia and covered for it so well that the family did not see it for years.</p><p>Tommy tells us that “At 70 years old now, you are less likely to be diagnosed with dementia than any other time in history.” The trajectory is not fixed, but there’s a lot more work to be done.</p><p>Enjoy the conversation.</p><p>____________________________________________</p><p><strong>Links & Resources</strong></p><p><strong>Dr. Tommy Wood’s Website: </strong><a href="https://www.drtommywood.com" rel="noopener noreferrer" target="_blank">drtommywood.com</a></p><p><strong>Dr. Tommy Wood’s Book: </strong><em>The Stimulated Mind: Future-Proof Your Brain from Dementia and Stay Sharp at Any Age</em></p><p><strong>BetterBrain, where Tommy is Chief Science Officer: </strong><a href="https://betterbrain.com" rel="noopener noreferrer" target="_blank">betterbrain.com</a></p><p><strong>Subscribe</strong> to our Youtube Channel for more conversations at the intersection of high performance, leadership, and wellbeing: <a href="https://www.youtube.com/c/FindingMastery" rel="noopener noreferrer" target="_blank">https://www.youtube.com/c/FindingMastery</a></p><p><strong>Get exclusive</strong> discounts and support our amazing sponsors!</p><p><strong>Go to: </strong><a href="https://findingmastery.com/sponsors/" rel="noopener noreferrer" target="_blank">https://findingmastery.com/sponsors/</a></p><p><strong>Subscribe</strong> to the Finding Mastery newsletter for weekly high performance insights: <a href="https://www.findingmastery.com/newsletter" rel="noopener noreferrer" target="_blank">https://www.findingmastery.com/newsletter</a></p><p><strong>Download</strong> Dr. Mike’s Morning Mindset Routine: <a href="https://www.findingmastery.com/morningmindset" rel="noopener noreferrer" target="_blank">findingmastery.com/morningmindset</a></p><p><strong>Follow</strong> on <a href="https://www.youtube.com/findingmastery" rel="noopener noreferrer" target="_blank">YouTube</a>, <a href="https://www.instagram.com/findingmastery/?hl=en" rel="noopener noreferrer" target="_blank">Instagram</a>, <a href="https://www.linkedin.com/in/drmichaelgervais/" rel="noopener noreferrer" target="_blank">LinkedIn</a>, and <a href="https://x.com/michaelgervais" rel="noopener noreferrer" target="_blank">X</a></p><p>See Privacy Policy at <a href="https://art19.com/privacy" rel="noopener noreferrer" target="_blank">https://art19.com/privacy</a> and California Privacy Notice at <a href="https://art19.com/privacy#do-not-sell-my-info" rel="noopener noreferrer" target="_blank">https://art19.com/privacy#do-not-sell-my-info</a>.</p>
Key Insights
- Wood argues that the historical belief in inevitable cognitive decline traces to Santiago Ramón y Cajal's 1906 description of the adult brain as 'immutable' and William Osler's early 20th-century characterization of people over 60 as useless, beliefs that persist despite modern evidence contradicting them.
- The Seattle Longitudinal Study found that over 50% of individuals maintain cognitive function from their 50s into their 70s and beyond, data that were used to raise the retirement age in the 1980s but never significantly changed public perception about aging and cognition.
- Age-specific incidence of dementia (likelihood of diagnosis at a given age) has been decreasing for several decades, primarily due to population-level improvements in cardiovascular disease treatment, suggesting that medical interventions addressing one system can have cascading benefits for brain health.
- Wood presents dementia risk through a systems model where Stimulus (cognitive engagement), Supply (blood flow and nutrients), and Support (recovery and adaptation) interact as an interconnected network rather than as independent, additive factors.
- Research shows that individuals with APOE4 genetic risk factor experience larger relative increases in dementia risk with poor lifestyle choices but also potentially larger absolute reductions in risk from addressing modifiable factors, suggesting genetics function as a risk multiplier rather than destiny.
- The Lancet Commission estimates that 45% of dementia cases could be prevented through modifying 14 risk factors, but socioeconomic status fundamentally determines access to most of these interventions, requiring systemic societal change rather than individual behavioral change alone.
- Wood notes that the brain requires acute stress and challenge for adaptation, similar to physical training, but chronic unresolved stress creates an 'overtraining picture' where the brain never recovers, potentially impairing sleep and neuroplasticity.
- The COSMOS trial, a double-blind placebo-controlled study, found that a basic multivitamin (Centrum Silver at 100% of recommended allowance) improved cognitive function, suggesting that filling nutritional gaps at population level may be more practical than pursuing megadose supplementation.
- Multiple randomized controlled trials demonstrate that homocysteine-lowering with B vitamins only produces cognitive benefits when omega-3 status is simultaneously optimized, exemplifying how isolated interventions fail when critical dependencies in the biological system are not addressed.
- Wood argues that the neuroscience field historically painted itself into a corner by focusing exclusively on protein pathology (amyloid and tau) visible under microscopes, when in fact people can have significant amyloid and tau accumulation without cognitive impairment, or minimal pathology with severe cognitive decline.
- Studies on subjective cognitive decline (when individuals notice changes before formal diagnosis) show this period is largely reversible through lifestyle interventions addressing cardiovascular risk, exercise, diet, and cognitive engagement, contrasting with the assumption that cognitive decline is progressive once noticed.
- Wood suggests that systems dynamics models used in engineering, featuring causal loop diagrams with feedback mechanisms, better represent biological reality than linear statistical models that assume independent additive effects, allowing identification of intervention points affecting multiple nodes in the network simultaneously.
Topics
Transcript
Right now, I think in the US, somewhere between 7 and 8 million people are living with dementia. Worldwide, 7 to 8 times that. And the burden of dementia is expected to double or triple in the next two decades. That's alarming. How much of dementia risk is actually within our control? They estimate that potentially 45% of cases of dementia could be completely prevented. There are other analyses that think it could be even higher than that. They include things like... Welcome back, or welcome to the Finding Mastery podcast, where we dive into the minds of the world's greatest thinkers and doers. I'm your host, Dr. Michael Gervais. Today's guest is Dr. Tommy Wood, physician, neuroscientist, associate professor…
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