Conversations about brain health have been dominated by a competing mix of fatalism and over-promising, with aging framed as inevitable decline and "brain optimisation" sold through weak evidence. So how should we think about cognition across the lifespan? In this episode, we explore the idea that neuroplasticity does not disappear in adulthood, but instead continues to respond, for better or worse, to repeated behaviours and exposures. Much of what is labelled age-related cognitive decline may in fact reflect an accumulation of modifiable risk factors. We also dig into how to critically evaluate brain-health claims and how lifestyle pillars such as exercise, sleep, diet, stress reduction and cognitive training fit into a coherent framework. The discussion extends to emerging multimodal intervention programs, their promising signals and their clear limitations, and to a broader, multifactorial view of Alzheimer's disease that moves beyond a narrow amyloid-centric model. Finally, we examine the role of genetics, including ApoE4, and why genetic risk does not equate to biological destiny, even later in life. Dr. Majid Fotuhi is a neurologist and an adjunct professor at the Johns Hopkins Mind/Brain Institute. He earned his medical degree from Harvard Medical School and completed a Ph.D. in neuroscience at Johns Hopkins University. That was followed by internship and neurology residency at Johns Hopkins Hospital. Timestamps [03:41] Understanding neuroplasticity [05:22] Risk factors for cognitive decline [07:07] Evidence-based interventions for brain health [09:37] The five pillars of brain health [10:42] Dr. Fotuhi's multimodal program [19:09] Measuring cognitive function [24:43] The role of amyloid and tau in Alzheimer's [27:53] Genetics and lifestyle in brain health [30:03] Debunking myths and overhyped claims [36:08] Key ideas segment (premium subscribers only) Related Resources Go to episode page (with links to studies mentioned) Join the Sigma email newsletter for free Subscribe to Sigma Nutrition Premium Enroll in the next cohort of our Applied Nutrition Literacy course Dr. Fotuhi's book: The Invincible Brain

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