In this episode of the Her Health Podcast, Laura Johnston sat down with Natasha Smit, a clinical neuropsychologist, for a powerful conversation on how the brain develops, how it changes over time, and what women can do to protect and strengthen their cognitive health. The discussion unpacked everything from neuroplasticity to lifestyle habits, offering practical tools that women in every age bracket could apply.
Rating Brain Health Trends: Natasha's Rapid-Fire Icebreaker
Laura opened the conversation with a fun, fast icebreaker where Natasha rated trending health tools from 1 to 10. In her responses, she prioritised evidence-based essentials like omega-3, exercise, and sleep, while being more cautious about viral trends.
She rated omega-3 a high 9/10, reminding viewers that the brain was 60% fat and relied heavily on essential fatty acids for optimal brain health. Exercise also scored a 9/10, particularly because of its impact on blood flow, which she called a key ingredient for cognitive performance.
More experimental trends such as cold therapy landed around 3/10, while dopamine detoxes dropped even further – a 2/10. Natasha emphasised that real results came from day-to-day dopamine regulation, not extreme resets. She showed cautious optimism toward compounds like PQQ and NMN, both earning 6/10 for their promising cognitive research.
50% Dementia Risk by Age 85: Why Brain Health Shouldn’t Be Ignored
Laura highlighted a statistic Natasha had shared off-air: 50% of people over the age of 85 suffer from dementia. She confirmed the figure and explained how deeply it troubled her, especially because lifestyle factors played such a significant role in dementia risk.
In the study, she explained that dementia began decades before symptoms showed, meaning that what women did in their 30s, 40s, and 50s had a profound impact on their long-term cognitive future. While society often prioritised skincare, fitness, and external markers of health, she reminded viewers that the brain drives everything – mood, relationships, ageing, sleep quality, and physical health outcomes.
“You couldn’t invest in your life if you didn’t invest in your brain,” she explained.
Sleep: The Brain’s Night-Shift Cleaning Crew
Natasha described sleep as one of the most powerful tools in preventing cognitive decline. During sleep, a “night-shift crew” moved through the brain to remove toxins, including proteins strongly associated with dementia.
If women failed to get proper deep sleep, these toxins stayed behind and accumulated over time.
She emphasised:
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7–9 hours of sleep was non-negotiable
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You cannot catch up on missed sleep
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Even a small amount of light in the room disrupted the circadian rhythm
Before using supplements, Natasha encouraged women to address their sleep hygiene, especially habits like late-night scrolling, screens before bed, or irregular sleep patterns. Supplements can be helpful, but only after behaviour has been corrected.
Movement for the Mind: Why Exercise Fuels Cognitive Health
Next, Natasha explained why physical movement is one of the most potent ways to preserve brain function. She noted that women have options – running, swimming, strength training, even racquet sports – and that the best form of activity was simply the one they could stick to consistently.
She highlighted the benefits of:
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Strength training for metabolic reserve
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Cardio for circulation
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Racket sports for fast-paced cognitive engagement
These activities boosted blood flow, stimulated neuroplasticity, and served as powerful protective factors against cognitive ageing.
Diet, Nutrients, and the Truth About “Expensive Urine”
When discussing diet, Natasha reiterated that the brain requires nutrient-dense foods – particularly from a Mediterranean diet – including healthy fats and adequate protein. She also shared a shocking statistic: The brain is 60% fat, and 98% of people are suboptimal in omega-3 levels.
She also addressed the common misconception that taking supplements simply produced “expensive urine.” In her view, the cost of nutrient deficiency was significantly higher, affecting everything from mood to behaviour, and potentially mimicking conditions like ADHD and even dementia in older adults.
Her advice for most people was to begin with a high-quality multivitamin to help fill nutritional gaps – and then build from there.
The 63-Day Cycle: How Long It Really Takes to Rewire the Brain
Natasha introduced researchers like Dr Caroline Leaf, whose work shows that true neurological change takes 63 days, not 21.
She explained how the first 21 days initiate the habit, but two more rounds of 21 are needed to break down old neural pathways, form new ones, and actually automate the new behaviour.
Natasha shared research showing that not only can habits be rewired, but the structure of the brain can physically change. One example was a famous study of London taxi drivers, whose hippocampus – the brain’s memory centre – was significantly larger due to years of spatial navigation.
The conclusion? It is never too late to rewire your brain.
The Stages of Brain Development: From Infancy to Adulthood
Natasha explained that when a baby is born, their brain is only about 25% of the size of an adult brain, yet by age five, it reaches approximately 90% of adult size. The first few years of life are marked by explosive brain growth, with roughly 700 new synaptic connections forming every second, enabling rapid learning and adaptability. After age three, the brain undergoes a process called pruning, which strengthens frequently used pathways and eliminates those that are less necessary. She explained how this process continues through childhood and adolescence, refining neural networks to optimise function. Natasha stated how brain development isn’t fully complete until the late 20s to early 30s, highlighting the extended period of cognitive growth and adaptability well into adulthood.
Dopamine Drips vs. Dopamine Dumps: Finding Balance in a Thrill-Seeking World
Natasha explained that in today’s fast-paced, stimulus-driven world, our brains are constantly exposed to dopamine dumps – intense bursts of pleasure that quickly deplete our reward system. She elaborated that these include doom scrolling, gambling, excessive alcohol, narcotics, pornography, or any activity that fuels the “just one more” cycle. While these behaviours create a temporary high, Natasha noted, they leave us feeling depleted, frustrated, and craving more.
In contrast, she described dopamine drips as small, intentional moments of joy that sustain happiness without overwhelming the system. Natasha suggested pausing to enjoy a sunset, linger on a delicious meal, or share a meaningful moment with a loved one as ways to generate steady dopamine, which can enhance mood, focus, and emotional resilience. She emphasised that by cultivating these mindful micro-moments, we can retrain our brains, reduce impulsive reward-seeking, and maintain consistent, balanced well-being.
Overcoming Negativity Bias: Rewiring Your Brain for Positivity
Humans are naturally wired with a negativity bias, an ancestral survival mechanism that made our brains more attuned to potential threats. While this was critical in caveman days for life-or-death decisions, today it often causes us to focus more on criticism than compliments, or dwell on negative events even after a positive experience. This default negative pathway is why the news feels overwhelmingly pessimistic and why our minds often fixate on worst-case scenarios. The good news is that our brains are malleable. Through intentional practices – like starting each morning with positive affirmations or setting the tone for your day – you can retrain your neural pathways. By nudging your brain to focus on the positive, you reduce stress, improve resilience, and gradually replace default negativity with a healthier, more optimistic mindset.
This episode served as a powerful reminder that brain health is both personal and actionable. Natasha encouraged women to prioritise sleep, movement, nutrient-rich eating, and ongoing learning, reinforcing that these daily choices have measurable effects on mood, memory, cognition, and long-term quality of life.
Most importantly, the conversation highlighted a message of empowerment:
women have far more control over their brain health than they realised – and it is never too late to start investing.
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This content is for informational purposes only and does not constitute medical advice. Always consult with your healthcare provider before starting any new supplement, especially if you are pregnant, nursing, have a medical condition, or are taking prescription or chronic medication.
