Neuroscientist Louisa Nicola explains how Alzheimer's disease begins in your 30s and how to prevent it
Steven Bartlett interviews neuroscientist and clinician Louisa Nicola on The Diary of a CEO.
Summary
Steven Bartlett interviews Louisa Nicola, a clinician and academic who has spent the past decade studying the brain, with a particular focus on Alzheimer's disease and women's brain health. Nicola argues that 95% of Alzheimer's cases are preventable through lifestyle intervention, and that the disease begins silently in a person's 30s, with symptoms only appearing decades later. She presents evidence that resistance training, sleep, hormone replacement therapy, and specific supplements — particularly creatine and omega-3 fatty acids — are among the most powerful tools available for prevention. She also speaks personally about her grandmother's death from cancer and how watching women suffer from preventable diseases drives her work.
Key Takeaways
FULL TRANSCRIPT
Introduction: What Alzheimer's disease is and why it matters now
Louisa Nicola: Over the last decade, I've been studying the brain. I'm both a clinician and an academic, so I get to see the brain and I also get to research it. And I'm really here to tackle one disease, and that is Alzheimer's disease.
Steven Bartlett: Why is this so important now?
Louisa Nicola: Right now, because 60 million people worldwide have Alzheimer's disease. That number is going to triple by the year 2050. 110 million women will have Alzheimer's disease by the year 2050. This is a disease that robs you of who you are, your complete identity. So we're going to get really into this straight away, because I brought Henry with me.
Steven Bartlett: And for anyone that can't see, Henry is a model brain that she's holding in her hands.
Louisa Nicola: This is around 2 lb. And if you actually feel a real human brain, it feels like tofu, but this is everything you are. And the fact that so many people are at the mercy of a disease that is preventable is not okay with me. It doesn't sit well with me.
We used to think that women were disproportionately affected by Alzheimer's disease because we lived longer, because age played a role in it. But we now have substantial evidence to show that it's not the fact that women live longer — because dementia and Alzheimer's disease are not part of the natural brain aging process. For women, and they differ from men, it is purely because being a woman is a risk factor for getting this disease.
Now, if we go through and look at all of the people that currently have Alzheimer's disease, 95% of them could have been prevented, because this is not a disease of genetics. It's a disease of lifestyle.
Steven Bartlett: 95% of it could have been prevented?
Louisa Nicola: Correct. We're born with our genetic makeup. For example, if you have a genetic mutation on chromosome 4, you will get Huntington's disease. There is nothing we can do about that. That's how you were born. But when it comes to Alzheimer's disease, there are around 20 to 30 genes involved in the disease. Only around 3% of the disease cases right now were driven through those genetic mutations — the genetic mutations that you are born with, that you get from mom and dad: presenilin 1, presenilin 2, and the amyloid precursor protein. If you have a genetic mutation in one of these genes, you will get some form of dementia.
The disease timeline: starting in your 30s
Steven Bartlett: What is the age range where people will start to experience Alzheimer's?
Louisa Nicola: Let's take a broad overview of what Alzheimer's disease is. You've probably heard of dementia. Dementia is the umbrella term. Alzheimer's disease sits under that umbrella — it's a form of dementia. There's frontotemporal dementia, which is what Bruce Willis has. There's dementia with Lewy bodies. There's Parkinson's dementia. There's vascular dementia. Alzheimer's disease is a disease of midlife. It generally starts in our 30s, but the first symptoms show up in our late 60s, 70s, and beyond.
Steven Bartlett: When you say it starts —
Louisa Nicola: Our brain fully develops at around 25 years old, 25 to 30. And after that, if we don't take care of our brain, we start getting a decline in these functions.
Now, the brain has 87 billion neurons, around 5 to 10,000 connections per neuron. My favourite area of the brain is the cerebellum, and the Purkinje cells inside the cerebellum have upwards of 50,000 connections per cell — so tightly dense, and there is so much happening. It takes 20% of the total calories that you consume every day to power this thing, and it's the most vascular-rich organ in the entire body.
Over time, through things such as sleep deprivation, poor diet, lack of physical activity, and environmental toxins, this slowly erodes the functioning of the brain. And over time, this starts to compound, because that's what biology is — everything is compounding. One night of sleep deprivation raises your risk of amyloid beta, which is one of the hallmarks of Alzheimer's disease pathology, by 4%. That's just one night of sleep deprivation. Imagine a new mother, or a shift worker, or a physician in their residency getting countless nights of sleep deprivation day in and day out. Imagine all of that compounding.
What happens? We end up with either neuronal loss, which is the complete atrophy of certain parts of the brain. And that's what mild cognitive impairment is. Mild cognitive impairment is a pre-dementia state.
Reading a brain scan: what atrophy looks like
Steven Bartlett: So what is this that I have here — this photo of a brain?
Louisa Nicola: You've got the sagittal view of the brain. We're looking at a healthy brain on the left-hand side. You can see that the brain is thick. The integrity of the gray matter, which sits on the outer portions, is thick and voluminous. The ventricles are smaller. Now we go over here and we see thinning of the cortex. You can see these big spaces between the gyri — the gray matter has atrophied, it's shrunk. You can see that the space between the cortex itself and the skull is bigger. You can see these butterfly-shaped ventricles — this is thicker, this is thinner. We can see atrophy down here. Essentially, the brain is getting smaller and smaller.
Steven Bartlett: At the age of 30, if I do everything right and we were to plot this on a graph of where I land at 70, what is the variance? My brain is quite important to me and I do worry. I sit and interview a lot of people at a lot of different ages, and one thing you notice as an interviewer is some people at 60 are razor sharp —
Louisa Nicola: And some people at 60 are not as razor sharp.
Steven Bartlett: Their ability to articulate their words, their memory recall, their ability to understand stats and stories — all of this. And I sit here and go, I wonder what the difference is.
Louisa Nicola: That's actually beautiful, because it brings up this important concept in neuroscience called cognitive reserve. That's your brain's ability to withhold capacity to overcome stresses. You've probably heard, for example, the analogy of physical performance — your VO2 max, which is a measure of your peak respiratory fitness, how well your body utilizes oxygen when you're at a high-intensity state. The fitter you are, the more reserve you have to overcome stress — stress such as an infection, everyday stresses, sleep deprivation, surgery. The more reserve you have in your bank to overcome that.
The same is true with your brain. The more cognitive reserve you have, the more cognitive capacity you've been training year in and year out, will save you at 60 from harmful insults. You can get a woman at the age of 80 with a head full of amyloid beta —
Steven Bartlett: Amyloid beta being —
Louisa Nicola: One of the hallmarks of Alzheimer's disease. You can get somebody with a head full of amyloid —
Steven Bartlett: Which is like a plaque on the brain.
Louisa Nicola: It's a protein that lives inside the neuron itself. You can have a head full of amyloid in this person and they have retained their cognitive functions. Then you can have somebody else with hardly any amyloid but they've lost their cognitive functions. And this all comes down to cognitive reserve.
Steven Bartlett: And cognitive reserve lives where in the head?
Louisa Nicola: You've got around 5 to 10,000 connections per cell. Over time, those connections fail. Those connections are responsible for your thinking, your processing speed. Every time you have a thought, you build a new connection. The more connections you have, the more things you see, the more novelty you give your brain, the richer it gets, the more stable it gets.
The ends of the neurons — we have dendrites. Coming off the dendrites are these little trees. Imagine a branch — that's the dendrite. And all of the leaves that come off it, all these little dendritic spines, they connect to nearby cells, up to 10,000 cells. Over time, those are the connections that fall. They fail because you don't utilize them.
Building cognitive reserve: exercise, reading, and the dangers of scrolling
Steven Bartlett: So the way that one would build reserve at the age of 30 is to —
Louisa Nicola: Exercise. We can build reserve in a number of different ways. In fact, there was a really wonderful study that just came out showing that those who preserved cognitive capacity at 75 years old were handwriting and reading. So handwriting and reading preserves cognitive functions. Exercise is one of the most potent stimuli for brain health, Alzheimer's disease prevention, and cognitive reserve. The more you exercise, the bigger your brain.
Steven Bartlett: What about scrolling on social media? Does it improve my reserve if I'm watching videos?
Louisa Nicola: It's the opposite.
Steven Bartlett: Why would that be? Because I'm still learning stuff when I'm on the internet.
Louisa Nicola: Because what you're doing is relying on short dopamine hits. Every time you scroll, you're sending signals to your brain that you're getting a dopamine hit. And your brain gets used to it. Remember, your brain is only there for two things: survival and reproduction. So every time you stress your brain in the smallest amount, you're giving it dopamine hits. It doesn't allow us to do other things for a sustained period of time — like focus, read, or have a conversation.
Steven Bartlett: So writing and reading are good for building up my neurological reserves.
Louisa Nicola: Yes, neurological reserves. But it doesn't compare to what exercise can do for the brain. And it's so sad, because around 80% of the US population don't exercise for at least 30 minutes a week, which is actually quite scary. The physical activity guidelines are 150 to 300 minutes of moderate to rigorous physical activity per week.
Steven Bartlett: What's the most compelling study you've ever encountered that proves that exercise is central to Alzheimer's prevention and brain health?
Louisa Nicola: When we look at all of the data, we can see that the biggest return on investment is from resistance training.
Steven Bartlett: Resistance training being —
Louisa Nicola: Strength training. One of the most compelling studies was probably the SMART trial, where they took a group of people with mild cognitive impairment and gave them two to three times per week of resistance training. They not only preserved their cognitive functions — they enhanced their processing speed, they enhanced their fluid intelligence, and they had a slowing of gray matter loss.
Steven Bartlett: The gray matter.
Louisa Nicola: Your brain consists of both gray and white matter. Gray matter is the cell bodies that live on the outer portions of your brain. White matter is deep within the brain, and that's where all of our myelinated neurons live. Over time, we can have little lesions in the white matter of the brain.
A lot of the time, people will say to me, "I'm scared — my mother had Alzheimer's disease, I'm scared I'm going to get it." We were talking about genetics before, and there's another genetic risk factor we didn't talk about. The APOE E4 gene is one of the strongest risk factors for getting Alzheimer's disease, but it is not a foregone conclusion that you're going to get it. Chris Hemsworth was tested and he has two copies of this gene.
You get two copies — one from mom, one from dad. It's the apolipoprotein E gene and it comes in three main variants: APOE E2, APOE E3, and APOE E4. I'm a 3/3 carrier — I've been tested, and that's the general population. It doesn't raise my risk of getting the disease, but it also doesn't protect me. If you've got a copy of the APOE E2 gene, it protects you against the disease. But when you have a copy of the APOE E4 gene, it raises your risk by two to three times. If you have two copies, it raises your risk by 10 times.
Here's the devastating thing. If you are a female with one copy of the gene, you are at double the risk of your male counterpart. So one copy of the APOE E4 gene for a female raises your risk by about sixfold, whereas two copies raises your risk by 15-fold.
Steven Bartlett: And how would one go and get checked?
Louisa Nicola: You can get the APOE E4 gene checked with your doctor. It's a simple blood test.
Why leg strength is the most important tool for brain health
Steven Bartlett: On this point of resistance training, I've heard you talk about how the legs are so important — having strong legs.
Louisa Nicola: Having strong legs is by far the most important tool in your toolbox for the prevention of Alzheimer's disease. And this was made certain to me when I read a study done on identical twins — exact same genetic profile. They tracked them, they did cognitive tests and MRIs, and they tracked them over a 10-year period. What they found was that the twin who possessed the greater strength and the most leg power had a bigger brain, larger gray matter volume. They preserved their cognitive functions. They did better on different cognitive tests.
Steven Bartlett: Why is resistance training increasing the size of my brain?
Louisa Nicola: Resistance training does so much for your brain. When you look at all of the studies, I want to make it really clear — all of the studies show that in order to produce the neural effects of resistance training, you need to be lifting at around 80% of your one-repetition max. That's quite heavy.
There is so much controversy on social media right now: should I lift heavy, should I lift light? When it comes to hypertrophy alone — increase in muscle mass, muscle cell size — you can get there by lifting light with high reps, or by lifting heavy with low reps. It just depends on who you are and how much time you have. But when it comes to the brain specifically, you want to be lifting heavy, for several reasons.
When we lift heavy, when we contract our muscles, we are releasing a whole set of chemicals called myokines. When they're released from the muscle, they go up to the brain and they do beneficial things for our cognitive performance, and they help with the growth and proliferation of new neurons in the hippocampus. The hippocampus is the first thing to go during Alzheimer's disease — it actually shrinks. This holds our memory. This is where a lot of our memory consolidation and learning takes place, which is why short-term memory is the first thing to go during this disease.
As we get older, what we've found is that you can grow new neurons in the hippocampus from structured and consistent exercise. The biggest growth is going to occur because of BDNF — brain-derived neurotrophic factor. This is a growth factor for the brain, and it gets released when we exercise. It gets released abundantly when we are doing aerobic training — when we're running, when we're cycling for long distances — but it also gets released when we do resistance training.
Here's the beautiful thing about it. When we do resistance training and we're releasing all of these myokines, these myokines are signalling molecules. They work together. We've got one called irisin — that's a messenger molecule. What it does is it actually helps BDNF express itself. So when we release this myokine, it goes into the brain, crosses the blood-brain barrier, and it tells BDNF to express itself. Then BDNF goes in and helps grow new neurons in the hippocampus.
But then we've got another myokine — let's take interleukin-6. Interleukin-6 comes from the interleukin family.
Steven Bartlett: What is that?
Louisa Nicola: The interleukin family is a class of pro-inflammatory cytokines. These get released when we are under stress, or when you've got an infection or a virus. But when we exercise, interleukin-6 — instead of acting as a pro-inflammatory cytokine, instead of creating inflammation — it acts as an anti-inflammatory cytokine. So it goes into the brain and it lowers inflammation. In fact, this was one of the first ever myokines to be studied, and they showed that interleukin-6 is also responsible for the downregulation of tumour cell growth. So exercise is a potent anti-cancer intervention as well, by way of myokines.
Steven Bartlett: How much exercise does one need to do to avoid the cancer-related side effects, but also the Alzheimer's problem?
Louisa Nicola: Just 30 minutes a day of aerobic physical activity can downregulate 13 types of cancers, the most prominent being breast cancer, colon cancer, and prostate cancer. These three have been studied most. You get your anti-cancer effects from the myokine release. Quite specifically, when we exercise, we're getting a robust release of something called natural killer cells. When we get these natural killer cells into the plasma and into the bloodstream, they go into the tumour site and they do what they were born to do — they kill. They go into the tumour site and start to kill the tumour. You can also get anti-cancer effects from the anti-inflammatory effects of resistance training and aerobic training.
These myokines are so powerful that pharmaceuticals are spending billions of dollars trying to replicate them. I want both men and women lifting heavy, because right across here lives your motor cortex. Think of your brain as real estate — there's real estate in your brain reserved for lifting heavy. Every time you lift a heavy weight as opposed to a light weight, it takes more neural real estate to lift that heavy weight. So the heavier you lift, the greater the neural drive. The greater the neural drive, the better it is for your brain.
Steven Bartlett: If you had to do just one exercise for the rest of your life to protect your brain and you could only pick one, what would it be?
Louisa Nicola: Deadlift.
Steven Bartlett: Why?
Louisa Nicola: If done correctly, the deadlift can use almost every muscle in your body — erect spine, glutes, quads, serratus anterior, calf muscles. There is so much compounding in that one lift. It would probably be comparable to a barbell squat as well.
The danger of being "active sedentary"
Steven Bartlett: According to the World Health Organization, we're getting increasingly more sedentary. There was this really interesting study done by the Cleveland Clinic about people who are "active sedentary." A major finding in 2025 found a danger of being active sedentary — people who exercise for 30 to 60 minutes but sit for the remaining 10 hours a day. If you sit for more than 10 hours a day, your risk of cardiovascular disease increases even if you meet weekly exercise goals, because prolonged sitting shuts down lipoprotein lipase, an enzyme essential for burning fat and cleaning glucose from the blood. That's annoying to read because I feel like that's me.
Louisa Nicola: Being sedentary is a disease. You can change the trajectory of your life by doing 10 air squats every hour on the hour. There was a study done on this that showed that if you do 10 air squats every hour, this can compensate for your sedentary lifestyle. Because unfortunately, this is the life we're living in. We are becoming more sedentary in our day-to-day lives. We're sitting more. We're not going out as much. There are younger kids on video games, they're scrolling. So much is happening that is involving our sedentary lifestyle, which is obviously increasing our risk of type 2 diabetes, cardiovascular disease, and so on.
Steven Bartlett: You can do it like this?
Louisa Nicola: There you go. 10 of those. If you do 10 of those, you can outweigh the benefits of a 30-minute power walk —
Steven Bartlett: Every hour?
Louisa Nicola: Yeah. Just get up every hour, or every 45 minutes, and do an air squat. This is primarily because when you eat, you get a massive spike of glucose. And the best way to bring that glucose spike back down is by doing any form of exercise — go out for a fast run, do an air squat, bring that glucose level back to baseline.
Zone 2 vs. zone 5 training, and the heart remodelling study
Steven Bartlett: Do you think much about aerobic training as a preventative measure for Alzheimer's?
Louisa Nicola: I love aerobic training. Women are facing a dilemma on social media because they're being given so much information. There is this huge uproar about whether to do zone 2 exercise or not.
Steven Bartlett: What is zone 2 exercise?
Louisa Nicola: We can think of physiology in zones. Zone 1 is what you and I are in right now. Zone 2 is the next level up — that's generally when we're exercising at around 60% of our maximum heart rate. It's where you're jogging but you can still have a conversation, where you're huffing and puffing. When we're exercising, we need to produce energy, and that energy starts in the mitochondria. We create ATP, and that's how we are able to perform the given task.
As soon as we get out of that zone and go into zone 3, zone 4, and zone 5, we're producing energy outside of the mitochondria, in the cytoplasm. In order to do that, we're breaking down glucose so fast via a pathway called glycolysis. The byproduct of that is lactate. Lactate is actually a fuel source for the brain — it's also a myokine.
A lot of women have been doing zone 2. They've been going to the gym and doing zone 2. And I'm trying to push women to get out of zone 2 for several reasons — not because it's not good for you. I think all forms of exercise are good for you. The more you move, the better. But a lot of people in midlife are busy, they're time-poor. Men actually get a greater return on investment by doing zone 2. Women don't get the same return on investment from zone 2.
So I'm trying to push women to first work on zone 5, zone 3, zone 4, zone 5. If they can, just do zone 5. Then do two to three sessions of resistance training a week. If you have time left over — and I've just described around 4 hours of exercise — then you can work in zone 2.
Zone 2 is great. If you're going to go out and go for a long run, you're doing many things. You are secreting a lot of BDNF, which we need. It's a growth factor for the brain. You're getting a massive amount of blood going into the brain, which delivers oxygen and nutrients. But what you're not doing is having a complete effect on the chambers of your heart.
Steven Bartlett: Is it better for me to do 5 km on a treadmill or outside?
Louisa Nicola: I would say it's better for the brain to do a smaller amount of exercise at a higher threshold. When you're outside, you've got so many things around you. Your brain has prime real estate — every part of the brain is responsible for a different function, from what you see to what you hear. You go outside and you can see so many things. You've got forward ambulation, which is going to help you with drive, motivation, and dopamine. You're also taking in sounds and senses. It downregulates inflammation. So you get so many other things from doing that. But comparing 5 km outside to 20 minutes of high aerobic physical activity — I would say the zone 5 is better for the brain.
The zone 5 training also does a lot for the chambers of your heart. We have a left ventricle and a right ventricle. The left ventricle delivers oxygenated blood to the entire body. It first gives blood to the brain, which means it's the most important part of your body. After it's done giving blood to the brain, it goes through to the rest of the body.
As we get older, we get stiffening of these arteries and something called left ventricular hypertrophy — where the left ventricle starts to get thicker. When it gets thicker, it's not as strong and can't pump as much blood as it could when it was younger.
Dr. Benjamin Levine — he's a sports cardiologist — did this landmark study which changed how I thought about zone 5 training. He took a group of sedentary males, average age around 50, and scanned their hearts. He then subjected them to around 4 hours of exercise per week, stratified as follows: one resistance training session a week, one high-intensity session at around 90% of maximum heart rate, and some longer moderate sessions in between. This was done over two years.
At the end of those two years, what he found was that he had remodelled the heart by 20 years. He reversed the age-related effects and defects of the heart by 20 years — essentially turning 50-year-old hearts into 30-year-old hearts just from physical activity alone.
Steven Bartlett: 4 hours a week for 2 years. And what kind of exercise was it?
Louisa Nicola: One of the protocols was exercising at 90% of your maximum heart rate. When we do this, we're generally looking at increasing our VO2 max. VO2 max, along with strength, is the strongest predictor of all-cause mortality.
If you want to improve your VO2 max, you want to do what we call the Norwegian 4x4 — it's the gold standard. You want to get your heart rate elevated to 90 to 95% for 4 minutes on, 4 minutes off, repeated four times. I actually do this twice a week. I do it on a stepper at the gym at around level 14, staying on for 4 minutes, then having a complete stop and rest for 4 minutes, and repeating that four times.
In that moment, I'm not just getting a massive shunting of blood to the brain. I'm not just getting a massive release of myokines and exerkines to the brain. I'm also remodelling the heart. I'm downregulating tumour cell growth. I'm improving my cognitive performance. I'm doing so much more than just exercising alone.
Steven Bartlett: So that's once a week in Levine's study that reversed these guys' hearts by 20 years?
Louisa Nicola: You only have to do that once a week, but he also did around 70% of maximum heart rate for around 2 hours a week, and he threw in one resistance training session. Consistency is key.
Steven Bartlett: I'm just looking at some of the findings of that study, and one of the surprising things is it showed that there is a biological expiration date for the reversal of the heart. The heart retains its plasticity — the ability to remodel itself — until the age of 65. If this intervention had started after the age of 65, the heart was too stiff to be physically remodelled to get that 20-year reversal. You have to start in late middle age.
Louisa Nicola: Exactly. So midlife is the window of opportunity for brain health and for longevity.
Steven Bartlett: I didn't realize you could remodel the heart yourself. That's interesting.
Louisa Nicola: You can remodel the heart. And the heart is amazing. The main blood supply for the brain exists in the vertebral arteries, which branch off the aorta from the heart. The vertebral arteries supply the posterior part of the brain and the cerebellum with blood. Then you've got the carotid arteries — one on each side, branching off the aorta — which supply the frontal and middle part of your brain with blood.
The brain is the most vascular-rich organ in the entire body. In times of stress such as hypertension — elevated blood pressure — we can actually kill off the tiniest parts of the blood vessels, which are called capillaries. They supply even the blood-brain barrier. They supply mainly the outer cortex of the brain with blood. When we have elevated blood pressure, we are starting to kill off those tiny little capillaries of the brain. Those capillaries are feeding different neurons in the brain and also feeding the blood-brain barrier. When we get a breaking off of these, we lose the blood supply, we lose the oxygenation, we get a breakdown of the blood-brain barrier itself — which is scary. We see this in patients who have mild cognitive impairment.
You've heard of leaky gut — we can call this leaky brain. The blood-brain barrier is like a bouncer of a nightclub. Those cells are all standing there, responsible for who can come in and who can't. They don't allow some molecules to get in. But over time, when this starts to degrade and become leaky, they start to spread apart. And when they do, you can have the passive diffusion of all these molecules coming in. That's really bad for your brain.
So we want to maintain the integrity of the blood-brain barrier by maintaining capillary health. We don't want the capillaries to die. They're one cell thick — any type of damage can damage them and kill them. Hypertension is one such cause.
There was a great study called the SPRINT trial, and it's now the gold standard for the recommendation of 120 over 80. When you have your blood pressure taken, we get the systolic over diastolic. Doing your blood pressure every day is a really great, inexpensive, and effective tool for maintaining good brain health. If you are hypertensive — anywhere over 135 systolic — that's when things start to break down, when we start to get the breakdown of those one-cell-thick capillaries.
In the SPRINT trial, what they found was that when they aggressively managed these patients and brought their blood pressure down pharmacologically through an ACE inhibitor, these patients preserved their brain gray matter and their cognitive functions. So we now have a gold standard. I would recommend anybody get an automatic blood pressure monitor — it costs about $25 on Amazon. Do it every single morning and watch your blood pressure.
Steven Bartlett: And then if it's high, what do I do about it?
Louisa Nicola: Outside of pharmacology, if we don't want to take a medication, we want to get stronger. We want to do this via exercise. Stress is one of the biggest things driving high blood pressure. Manage stress, manage cortisol, manage chronic inflammation by way of exercise, sleep — all of the things that mother nature gave us.
Steven Bartlett: I was just looking at the study that reversed the heart by 20 years and trying to figure out what exercises they did. As you said, the first one was a high-intensity workout, the 4x4. Then they did a long aerobic exercise — again, all once a week — so 60 minutes once a week doing a longer exercise like hiking, tennis, or cycling. A moderate-intensity workout, 30 minutes, where they did the talk test — you should be able to break a sweat but still be able to speak. And then lastly, strength training once a week. So it's really a variety of exercises that caused such a profound impact on the heart.
Louisa Nicola: And cardiovascular disease — dementia is the number one killer of women in the UK.
Steven Bartlett: Really. It's the number one cause of death in Australia for both men and women.
Louisa Nicola: How does it kill you? Because we all think about memory loss and stuff like that, but the actual devastating part is this: we don't die of Alzheimer's disease specifically. Over time, in these patients — and you have to remember, Alzheimer's disease is like end-stage cancer. Once you get the diagnosis, there is no cure. There is no going back. There is no reversal. You have the disease, and that's the scariest part.
Mild cognitive impairment — you can slow the progression of that. Like I said, it goes for 20 years. But as soon as you get diagnosed on that awful day, it's a sad day. What ends up happening with these patients is you can die of asphyxiation. Your brain loses the signal to swallow. It loses the signal to maintain balance, so maybe you fall. It's a really scary moment, but it's not like you die of Alzheimer's disease specifically.
Steven Bartlett: If you were diagnosed with Alzheimer's disease, I would have no hope. I think a better question is —
Louisa Nicola: You'd have no hope.
Steven Bartlett: If I was diagnosed with Alzheimer's disease, there is nothing I could do. How would that change your life and the decisions you make?
Louisa Nicola: I would aggressively exercise. I would monitor my diet. I would aggressively monitor my diet and I would potentially have a ketogenic diet, because what we've found is that during this metabolic crisis that happens in your brain — where you lose the ability to use glucose as your primary fuel source — the brain doesn't know how to use glucose as its primary fuel source. So it's under attack.
The brain's metabolic crisis: ketones, menopause, and estrogen
During Alzheimer's — but also during the perimenopause state for women — when the brain cell is under attack and it can't utilize glucose effectively and it doesn't have any energy, it starts to think about survival. It starts to break down the myelin sheath. The astrocytes — they're the supporters of the brain cells — start to think, let's break down the myelin sheath. From that, the astrocytes produce ketone bodies, and then the ketone bodies get shuttled into the brain. That's how we use energy in the brain in that state of metabolic crisis.
So I would make sure that I am having a ketone-rich diet or getting exogenous ketones. I would aggressively exercise. I would aggressively manage my lipids. I'd have a high intake of omega-3 fatty acids. And I would preserve, if I could, any form of cognitive function by way of talking to people, going outside, socializing, having hard conversations if I was intact and could do so. I would throw tennis balls at the wall.
Steven Bartlett: On that point of the ketogenic diet — the reason is because ketones are an alternative fuel source to glucose.
Louisa Nicola: And the brain likes ketones.
Steven Bartlett: The brain loves ketones.
Louisa Nicola: It actually utilizes them more effectively than glucose. But glucose is the primary fuel source for the brain. And here's what's really interesting and devastating for females during the onset of perimenopause — when we see a decline in estrogen, what happens is a 30% reduction in brain glucose metabolism. When these receptors start to die because we don't have a lot of estrogen circulating in the bloodstream anymore, we can't utilize glucose as effectively. So during that state, that's when we start to get the breakdown of the myelin sheath, to use that as ketone bodies as an alternative brain fuel source.
Steven Bartlett: So do you think women going through menopause should be considering a ketogenic diet?
Louisa Nicola: Yes, I do think that women who are going through perimenopause and who are at the mercy of this brain energetic crisis should be adopting, if they can, a ketogenic diet. It's one of the best diets for the brain.
Steven Bartlett: I didn't really understand this idea that during menopause there was a glucose deficiency or metabolism problem in the brain.
Louisa Nicola: A 30% reduction in brain glucose metabolism.
Steven Bartlett: Is this why women report having brain fog and all these kinds of things?
Louisa Nicola: Yeah, absolutely. Because when the brain can't utilize its fuel source effectively, metabolites start to shift. We don't sleep properly. Around 60 to 65% of women in menopause report having a hot flash or night sweats. It wakes them up at night. That's also causing cognitive decline and brain fog.
Steven Bartlett: Can you explain what this graph shows?
Louisa Nicola: This is showing the estrogen levels at birth going through all of the life cycles that a woman will go through — puberty, perimenopause, and then eventually menopause. There is one thing that is certain. After age — I mentioned earlier that being a woman is the next strongest risk factor for getting this disease — and that largely lies in our menopausal shift, the downsizing of estrogen. However, we do have forms of estrogen that we can supplement with.
Steven Bartlett: So I just need to keep the estrogen up, because then the brain health is going to be up and normal.
Louisa Nicola: This is where the controversy lies. Yes and no. I want everyone to understand — my entire doctoral thesis is focused on women and Alzheimer's disease, and I'm Switzerland right now when it comes to hormone replacement therapy.
Steven Bartlett: You're Switzerland.
Louisa Nicola: Meaning that there is no evidence to suggest — right now we don't have large-scale randomized control trials to show that hormone replacement therapy prevents dementia. So what I will tell you is this: it is a signal, it is a supporter, it will help you do the things that can lower your risk of dementia. We've seen multiple times that having hormone replacement therapy can reduce your risk of getting Alzheimer's disease by up to 30%. We know that. But it's not because estrogen alone is minimizing your risk.
It's because when you have estrogen, it helps get rid of the hot flashes. It helps with the night sweats. During menopause, when we have a dysregulation of estrogen in our brain, what happens in the hypothalamus — which is an area in the brain that controls our temperature regulation — when we lose the ability to monitor our temperature, the hypothalamus doesn't know what to do. So when a woman feels the slightest bit hot, it signals that she's super hot, raises her temperature right up — and that's a hot flash. Then it brings it right down. And as a result, this is keeping women up at night. We know that sleep deprivation is a risk factor for Alzheimer's disease. Compounding sleep deprivation will accumulate amyloid beta in your brain.
So if we can use hormone replacement therapy as a signal and as a support to help us sleep at night, then that's a good thing. Another thing — estrogen is anabolic to muscle.
Steven Bartlett: What does that mean?
Louisa Nicola: It means that it helps with muscle protein synthesis.
Steven Bartlett: Oh, it helps me make muscle.
Louisa Nicola: Yeah. We've got estrogen receptors on our bone. We've got estrogen receptors on our muscle. So if estrogen is anabolic to muscle, if estrogen helps with muscle protein synthesis, if estrogen helps with bone mineral density, then replacing estrogen during that menopause state is going to help us with all of the risk factors of Alzheimer's disease.
Steven Bartlett: When does estrogen — in this image it really drops off a cliff.
Louisa Nicola: It varies. It tends to generally happen at around 45 years old as an average, and that perimenopause stage lasts around 10 years.
Steven Bartlett: But it starts going down on this graph at about 30.
Louisa Nicola: It starts to go down, and everyone's different. You can have a woman in her late 30s go into perimenopause. The general age is around 42 to 45. Most OBGYNs that I've spoken to say that you need to start checking in with your doctor at around 40 years old to check for this.
Steven Bartlett: Thinking about my fiancée now — do you think that someone like her should go on hormone replacement therapy at like 40?
Louisa Nicola: That's the big question. That's the elephant in the room. Should you go on hormone replacement therapy or should you not? And that's definitely a conversation between you and your physician. However, we've got large-scale studies right now to show that we don't have to be afraid of hormone replacement therapy.
Without going too deep into the weeds, there was a massive study done — the Women's Health Initiative — that scared women out of taking hormone replacement therapy in fear of getting breast cancer.
Steven Bartlett: Correct. We went from having 40% of women on hormone replacement therapy to just 4% of women on hormone replacement therapy.
Louisa Nicola: We know that even at the onset of menopause, a woman's risk of having a heart-related event triples. A woman's risk of getting Alzheimer's disease increases. So there is something to posit here about the benefits of hormone replacement therapy that we still haven't yet fully studied.
Steven Bartlett: Will you do hormone replacement therapy?
Louisa Nicola: I definitely will.
Steven Bartlett: And what kind of hormone?
Louisa Nicola: So this is really interesting. This is estradiol and progesterone. Progesterone is the one that's going to help you sleep at night. This one here is vaginal estrogen — it's a cream that gets inserted. And apparently, if you put vaginal estrogen on your face, it's probably the best form of skincare you could ever have. We have estrogen receptors all over our tissues, including our skin. These are estradiol inserts. If you get vaginal estrogen in the form of a cream, you can put it on your face and it can help with skin elasticity, collagen, and dermal thickness. This is actually what I'm most excited about.
Steven Bartlett: Are these the only ways that one can do hormone replacement?
Louisa Nicola: No, there's also a patch — the transdermal patch — and that's what most women are opting for.
Steven Bartlett: When the time comes?
Louisa Nicola: I will probably do the patch. Because it's the easiest. That's the one I've researched the most. I'm not afraid of hormone replacement therapy in the slightest. You do have to check with your doctor, but I definitely think this is going to be one thing that is going to help with the Alzheimer's disease crisis that is occurring.
The biology of Alzheimer's: amyloid beta, tau protein, and the glymphatic system
Louisa Nicola: I mentioned earlier plaques. A lot of people ask what distinguishes Alzheimer's disease from the rest of the dementias, and it comes down to two proteins: amyloid beta and tau protein.
Here's where it gets really interesting, and it actually dates back to 1901. The first ever Alzheimer's disease patient — Augusta — she was 52 years old. She and her husband went to the hospital, complaining of difficulties with word finding and word fluency. She couldn't remember where she put her keys, and her husband said she was delirious. Augusta told the doctor on board — he was a psychiatrist, his name was Alois Alzheimer — she said to him: "I don't know who I am anymore."
As I mentioned, this disease robs you of who you are. In 1906, Augusta died, and that was the first ever patient to be recorded as having Alzheimer's disease. Postmortem, they cut her brain open and found that she had these plaques in her brain. They didn't really understand what it was, but that was the first ever induction of this disease in society.
Ever since then, we are still trying to tackle this disease. In the 2000s, we had this notion that Alzheimer's disease was the amyloid cascade hypothesis — meaning that Alzheimer's disease is what happens when you get a head full of amyloid, this toxic protein that builds up. So we were demonizing this peptide protein. Then came the medications in the form of IV drugs. You go to the hospital, you get an IV, with the promise that it will clear out amyloid. But what they found was that when they were taking out the amyloid in these brains, they were taking with them brain tissue and causing microhaemorrhages. In some patients, it was resulting in death.
So we now know that the problem here isn't amyloid. In fact, amyloid is an antimicrobial peptide — it's actually a good thing. Amyloid beta protects the brain cells.
Now, here's what happens. We have this beautiful process during sleep. When we get into deep sleep, we activate the glymphatic system. The glymphatic system comes from the word "glia" — glial cells. We have glial cells in the brain that sit outside of the neurons, and these are responsible for immunity — they're our chief immune response cells. During deep sleep, they shrink, and when they shrink, all of this amyloid beta that's floating around in the cerebrospinal fluid gets washed out. It's like a washing machine that occurs in your brain.
But what tends to happen in Alzheimer's patients is they don't get a chance to wash out the amyloid. What happens in perimenopause and menopause — due to the hot flashes — is you don't get to get into deep sleep because you're having a fragmented sleep, waking up due to hot flashes and night sweats. That is what's causing the buildup of amyloid.
Now, we've got another protein that is a hallmark of Alzheimer's disease: tau protein. Tau lives in the axon of the cell — the one covered in the myelin sheath. Under times of stress, this tau protein phosphorylates. It breaks off. Tau protein normally stabilizes the microtubules — imagine these railroad tracks in the axon, just going up and down. The tau proteins keep the microtubules intact, so the trunk of the tree is stabilized. Why does it need to be stabilized? Because that's how speed of thought travels. Information processing speed travels up there.
When the tau protein phosphorylates, it starts to form tangles — they're called neurofibrillary tangles. And when all these tangles clump together, we get the collapse of the axon, the collapse of these microtubules. So we're not just having a cascade of environmental disaster inside the cerebrospinal fluid of the brain and outside the cells — we've also got this cascade happening inside the cell body itself. The brain is under attack inside the cell and outside the cell.
Steven Bartlett: Why? Why exactly does this happen?
Louisa Nicola: Because of how we treat our brains. The reason why these tau proteins are hyperphosphorylated is because of many things. One is that we have estrogen receptors on the brain cells themselves, in the axon. When we don't have adequate estrogen, estrogen is actually so smart — what it's doing is blocking an enzyme that is responsible for phosphorylating the tau. So if we don't have the estrogen there, the enzyme is there to phosphorylate the tau and break it down and cause these neurofibrillary tangles.
But let's just say you're a man and you don't need the estrogen there — although testosterone is neuroprotective. Testosterone actually aromatizes into estrogen, which is why men have an extra added protection. What else causes this? Stress. Sleep.
Steven Bartlett: You're talking about sleep there.
Louisa Nicola: Sleep is, I think, by far the most underrated Alzheimer's disease prevention tool that we have. It's underrated because we have been doing it all our lives and we think that we can just go to sleep and the magic happens. But I think now in 2026, we actually need to train for sleep. During deep sleep, we activate the glymphatic system, and sadly a large proportion of us aren't getting into deep sleep.
Steven Bartlett: How do you sleep?
Louisa Nicola: I make sure I sleep 7 and a half hours a night.
Sleep deprivation, the glymphatic system, and how to optimize sleep
Steven Bartlett: A lot of people struggle with sleep and they've just kind of gotten used to it. I hear this from friends of mine who will say, "I'm a bad sleeper, I'll sleep for 5 hours," and they've kind of just gotten used to it. Do you think that's okay?
Louisa Nicola: No. And they will pay for this in their 60s and 70s.
Steven Bartlett: How do you know?
Louisa Nicola: Because I know that just one night of sleep deprivation is raising your risk of amyloid beta by at least 4 to 5%. Just one night. So you can imagine the accumulation of this. Not only that, we know that you're interrupting the hormones responsible for hunger and satiety. We know that you're increasing your risk of type 2 diabetes with sleep deprivation. But not just that — we also see that this compound effect can't be reversed. A lot of people think, "I'll just sleep for 6 hours a night and then bank on it on the weekend." But sadly, that's not how our brain works. It's not like debt that we can repay to the bank.
Steven Bartlett: I heard from Matthew Walker the other day though that we can save it up. He said you can't make up for lost sleep, but if on Monday I've got something where I know I'm going to be deprived, he says on the weekends — Saturday and Sunday — if I got a huge amount of sleep, it's kind of like I can use that.
Louisa Nicola: Yeah, it's kind of like the reserve. Actually, I do this. I do long-haul flights — it's like 6 hours between LA and New York, but also to Australia. So if I know I'm going on a long-haul flight, I'll bank on my sleep for about a week leading up to that, because I know I'm going to be sleep-deprived on the plane.
So if you were one of those people that struggles with sleep, and you're slightly concerned — you've heard about this glymphatic system which comes out at night and cleans up the brain, and you're thinking, my glymphatic system isn't going to be optimal if I'm not sleeping — what would you do about it?
I would get really serious about examining my lifestyle the day before. This generally involves two things. You have to ask yourself: are you having trouble falling asleep, or are you having trouble staying asleep?
A lot of women report trouble falling asleep — they've got a racing mind. Men too. They can't stop that default mode network and the racing thoughts. And then there's the "I can't stay asleep" — meaning I'm waking up due to heat, I'm waking up because I'm stressed and having bad dreams. There are all different reasons as to why you wake up.
For the person who is having trouble falling asleep at night, I would strongly recommend introducing a supplement called GABA — gamma-aminobutyric acid. It's our chief inhibitory neurotransmitter. When you have this, it really helps stabilize all those thoughts. It helps with a racing mind and it can help calm you down at night.
The next thing I'll do is think about what I'm eating. It turns out that eating starchy vegetables — sweet potatoes, for example — backloading your carbs at night has a better benefit for helping you sleep.
If you start training for sleep as if sleep is your marathon, and start preparing for that at 8:00 p.m. — getting off email, not having any hard conversations, not watching anything crazy at night — you'll settle your mind down, you'll settle your nervous system down.
But where I think most of the optimization occurs is when you're actually in sleep. I would also work on sleep regulation. In order to fall asleep and stay asleep, our core body temperature needs to drop at least 2°. I'm doing this with a temperature-controlled mattress, because it's working on thermal regulation. A lot of people who don't have that can do several things — sleeping with their feet outside of the sheets, or turning the air conditioning on to cool the room and bring down your core body temperature.
One thing you can supplement with is glycine, which I think is amazing because it helps with sleep by way of temperature regulation. It can bring down your core body temperature. And glycine itself has one of the greatest longevity benefits for improving lifespan. So taking glycine can also help with that.
Steven Bartlett: What about ashwagandha?
Louisa Nicola: Ashwagandha is great. Ashwagandha and rhodiola — what they both are is adaptogens. An adaptogen is great because it goes in and adapts to what is happening in your body. Let's say you have elevated cortisol — this tends to happen during different cycles during the day, mainly during the daytime when we wake up and cortisol levels are at their peak, but it can also happen at night. Having this can actually stabilize that cortisol. It can go in, combine with cortisol, and bring it down. Conversely, if something is low, it can bring it up. So it's really good.
Studies show that you can actually take this three times a day and you won't feel fatigued. It doesn't disrupt anything and it pairs really well with caffeine. So does theanine. This is actually a really great adjunct to your supplement stack.
Steven Bartlett: And you really talk about how you need to sort of warm down to go to sleep, starting at like 7:00 p.m.
Louisa Nicola: Starting at around 8:00 p.m. And that's in line with circadian rhythm and circadian biology. When it comes to sleep and your circadian rhythm, you kind of want to mimic the sun and mother nature. When does the sun start to go down? It starts to go down at around 8:00 p.m. depending on where you are in the world. And when this happens, we also get the natural release of melatonin — that sleepy hormone that gets released in response to darkness. This may also be another reason why somebody is having trouble falling asleep and staying asleep.
So we want to get the natural release of that. Sleeping with a red light mask on, dimming the lights — I've actually replaced all of my light bulbs at home, including in my bedroom, with red light bulbs. So I'm getting rid of the blue light, the junk light, and replacing it with red light to help downregulate the nervous system. I do wear blue light-blocking glasses. Do I think they're providing an immediate and huge benefit? I don't know. But they could have a minor benefit. So warming down involves doing these things that are going to help you downregulate your nervous system so you can fall asleep faster.
Omega-3, vitamin D, and supplement quality
Steven Bartlett: Sticking on supplements for a second — omega-3. I've got two of them here. But when I brought both of them out, you said I've got to be quite careful about what brand I buy, but also something about temperature.
Louisa Nicola: By far, out of all of the supplements, omega-3 is probably the only one where you have to make sure you look at the supplement label carefully. There was a study done that showed that around 95% of the most popular omega-3 supplements in the US — about 85 of them were tested — exceeded the normal oxidation level. These pills, because they're omega-3 fatty acids from fish oil, they are oil, and they can become rancid and oxidized. They usually do this when they're in a heated environment.
Here are the rules of thumb. One, you want to look for a manufacturer that is highly credible and certified — NSF certified. That's an external governing board that certifies them on everything: heavy metals, oxidation levels, and making sure that what's in the capsule is actually in the capsule. That's another thing that is scary — the supplement industry is highly unregulated.
And I treat my omega-3s the same way I treat my olive oil. You want to get oil that is sourced in the area that you are. We're in California right now, so you might want to find an omega-3 that is sourced in California.
Steven Bartlett: Do I want to put it in the fridge?
Louisa Nicola: You want to put it in the fridge the moment that you get it.
Steven Bartlett: Really? Why does nobody talk about that?
Louisa Nicola: It's just the same as olive oil. You don't want the olive oil to become rancid, so you don't leave it near the stove. You want to put it in a cupboard away from the stove.
Steven Bartlett: And these are good for the brain.
Louisa Nicola: Omega-3 is by far one of the most potent stimuli you could have for the brain. They help with cell membrane fluidity. Where your cells meet — neuron to neuron — they create something called a synapse. In order for that to occur, we have a massive influx of all of these neurotransmitters — dopamine, serotonin — as well as calcium and potassium. These help our brain cells communicate. We want to make sure that our cell membranes are fluid and they glide, in order to help with that synaptic transmission.
Another thing they do is they are comparable to an NSAID — an anti-inflammatory medication. These have massive anti-inflammatory effects. In fact, I think they have the safety profile of an FDA-approved drug, and there are only benefits from them — no side effects.
Not just that — 60% of our brain is made of fat. 70% of that is made of DHA. And DHA comes from omega-3 fatty acids. So why would I not want to replace the fat in my brain with what it's made of? That's what you do when you have omega-3 fatty acids.
In fact, there have been several trials to show that omega-3 fatty acids are most beneficial and most effective for mild cognitive impairment patients, people who have the APOE E4 gene, and people who have Alzheimer's disease. Because when I told you that we get the breakdown of the blood-brain barrier, those cells on the blood-brain barrier require DHA. There's actually a transporter on the outside of our brain that allows the DHA to come in and get into the brain.
Steven Bartlett: And I know you're a big fan of vitamin D as well, because there have been some very encouraging studies done there.
Louisa Nicola: Vitamin D is phenomenal. We have vitamin D receptors all over our brain, brain stem, and they're abundantly found in the hippocampus and the memory centres of our brain. There was actually a study done on centenarians in China — those who lived to 100, but it was done in women. They showed that the women who preserved their cognitive functions and who didn't get Alzheimer's disease had high levels of vitamin D. They weren't vitamin D deficient.
In fact, being vitamin D deficient can increase your risk of all-cause dementia by 40%. Conversely, having a high level of vitamin D — around 60 nanograms per decilitre — can lower your risk of getting Alzheimer's disease by around 80%.
Creatine: the most underrated supplement for brain health
Steven Bartlett: And then we have this white powder in front of me.
Louisa Nicola: You've got a big smile on your face. I do, because there is just so much benefit to this. Depending on which brand you've bought, of course, but I can't say enough about creatine. I have my parents on creatine — they're 71 years old. I've got my dad on high-dose creatine. I've got my mother on low-dose creatine. It's the most widely studied supplement on the market.
Steven Bartlett: I've never seen you this excited.
Louisa Nicola: I'm so excited because I think this is a really cheap and effective way to get everything you want from both your physiology and your neurophysiology. Let's actually talk about creatine, because I know it gets a lot of air time, but women and men are still scared of it. They're scared of it for two reasons. One, they're scared it's going to cause kidney damage. And two, they're scared their hair is going to fall out. I'm going to address both of those fears.
First, let's talk about what it is. Creatine is a naturally occurring molecule. We produce around 2 to 3 grams of creatine per day — secreted from the brain, but a lot from the liver. Two to 3 grams a day is great, but it's not enough. So we have to supplement with it.
All through the 90s and 2000s, people were supplementing with 5 grams a day. Now that we're getting more rigorous with our brain health studies, we have found that creatine has enormous benefits for the brain. But here's the problem. When you have 5 grams of creatine, you're saturating the muscles. The muscles are so hungry, so they get first dibs and they take up all of that creatine. So then there's none left for the brain. We also lose a bit of the bioavailability when the creatine goes into the brain — it crosses the blood-brain barrier, but we lose some of it. So we have to supplement with more than 5 grams.
One of the studies that changed my thinking came out last year. It was the first ever pilot study done on Alzheimer's disease patients — patients whose brains are under attack, in an energetic crisis. They cannot produce energy effectively. ATP is all skewed. Brain glucose metabolism is skewed. They don't remember left from right. Cognitive functions are declined. They put them on 20 grams of creatine per day.
Steven Bartlett: Which is how much?
Louisa Nicola: That's four of this scoop. You probably want to have this spread throughout the day — which is what I did. I had 20 grams today: 5 grams in the morning, 5 mid-morning, and then 10 before I got here. And what they found was that these patients not only preserved their cognitive functions, but they had more energy and they were able to exercise more. It blew my mind. It doesn't matter how old you are. Creatine doesn't discriminate based on gender, age, weight, pathology, disease state, or ethnicity. It is just there to support you. It's the most widely studied supplement on the market.
Steven Bartlett: And it's all reward.
Louisa Nicola: It's all reward. There is no risk. It's helping with cell energy metabolism — basically, it's helping ATP create energy. So if you're someone that is low energy, you should definitely be having creatine. I don't care who you are, you should definitely be having creatine.
Steven Bartlett: People with brain fog —
Louisa Nicola: Yeah, people with brain fog. One of the greatest benefits is for men who are in football. At high doses of creatine — around 30 grams a day — it can protect you against insults, meaning you take a hit to the head like a concussion. It can protect your brain against a concussion. It can protect your brain against a stroke. It can protect your brain from stress. The best thing about creatine is that it works in the background of stress. That's where you'll get most of the benefits from.
Steven Bartlett: After hearing so much about creatine on this podcast, I started recommending it to all of the people in my life. There's one particular person who had gone through cancer treatments and survived, but in their words wasn't the same on the other side of the cancer treatments. I talked to her about creatine, and she said to me the other day — I think the exact quote was —
Louisa Nicola: "I feel like I've got my life back."
Steven Bartlett: Because she's been taking creatine every single day for the last 5 months or so.
Louisa Nicola: It's funny you said that, because just recently in the last two weeks, a study was done to show the anti-cancer effects of creatine. If my memory serves correctly, they dosed it at 0.36 grams per kilogram of body weight. So if you are a 70-kilo person, you're looking at around 25 grams of creatine per day that can have anti-cancer effects.
Steven Bartlett: The study I'm referring to — I'll put it up on the screen as well for anyone that wants to see it. It's the NHANES 2025 study, which is a major study involving over 25,000 adults. It found a linear negative association between dietary creatine and cancer prevalence. For every standard deviation increase in dietary creatine intake, the risk of having cancer decreased by roughly 5% to 18% depending on the demographic.
Louisa Nicola: That is wild. This protective association was strongest in adults over the age of 50, suggesting that as we age, maintaining higher creatine levels might be more critical for cellular health and immune surveillance.
If you think about life and think about energy — we need energy to survive. We need energy to fight off infections. We need energy to fight off stress, to preserve our normal bodily functions. When we are at the mercy of a low energy crisis, we can't fight off tumour cells, we can't fight off these debilitating diseases. So it actually makes sense that with more energy and with more functional energy — if our cells can function better — you can see a reduction in cancer incidence. Likely you can also see a reduction in Alzheimer's disease incidence.
When I said that creatine works in the background of stress — there's also been phenomenal research to show that you can basically creatine your way out of sleep deprivation. If you've had a long night and you're sleep-deprived — maybe you slept four, five, 6 hours — you can take high-dose creatine in the form of around 15 to 20 grams a day and you can reverse the negative effects associated with that sleep deprivation.
Steven Bartlett: Does it matter what time you take the creatine?
Louisa Nicola: It doesn't matter what time you take the creatine. It doesn't degrade in hot water. You can take it any time throughout the day, and it doesn't matter whether you're taking it right before exercise, during exercise, or after exercise — it works phenomenally. Some researchers are now wondering if taking it at night before bed helps with sleep performance, and I think that's a really exciting area.
But the one thing I want to tell everybody — because a lot of people are scared of this biomarker called creatinine —
Steven Bartlett: Oh, my doctor said that to me.
Louisa Nicola: Meaning that you've got a high creatinine level. This is a marker of kidney function. But this is where I find it really invaluable. A lot of people say, "Well, I had so much creatine that my doctor told me to get off it because my creatinine levels were high." But creatinine levels are high during times of stress, during times of intense physical activity, and also in people who have a lot of muscle mass.
What you want to test — a greater marker of kidney function and GFR — is cystatin C. All you have to do is ask your doctor: "Could I please get cystatin C in my blood work?" If that is elevated and not within normal range, then maybe get off creatine. But right now, I cannot see any reason not to have creatine every single day. I think every single person, no matter what age, should be supplementing with creatine.
Now, there was a recent study that came out on menopausal women — a small randomized control trial. They split women into four groups: low-dose creatine at around 750 mg a day, medium dose at around 1.5 grams a day, a range of both creatine monohydrate and creatine hydrochloride, and a placebo group. What they found — and it was a very small study — was that those in the medium range having 1.5 grams had substantial increases in their mood and their cognitive functions. So creatine is now being explored in females across the lifespan as it relates to perimenopause, pregnancy, menopause, and dementia.
The only thing I want to point out — when it comes to creatine, look for two things in terms of manufacturing standards. Has it been NSF certified? And is it Creapure? Creapure is the gold standard of creatine and it comes from Germany.
Steven Bartlett: Excuse me.
Louisa Nicola: I know my creatine.
Steven Bartlett: How can you tell what it is by looking at it?
Louisa Nicola: I can just tell. I bet you a million dollars that it is the brand I think it is, because it's got this powdered icing sugar substance. If it was pure gold standard Creapure, it would be gritty. The reason why it's like this is because a lot of manufacturers want to add different agents in order for it to mix well. This probably mixes really well. A lot of people also complain of feeling GI distress when they take it. And all I have to say is that's not a reason to stop taking it. Maybe take 2 grams at a time, maybe take 3 grams at a time, but don't stop taking it.
Testing your health: what to check and how often
Steven Bartlett: What do you test for with your own health and how frequently do you test?
Louisa Nicola: I test every 3 to 4 months.
Steven Bartlett: What do you test?
Louisa Nicola: Oh, I do everything. I just did lab work on December 15th, the day before my birthday. But every year, funnily enough, I test my biological age.
Steven Bartlett: What is your biological age?
Louisa Nicola: It came back as 22.
Steven Bartlett: Okay. What's the most important test they don't typically do that you think everybody should be doing?
Louisa Nicola: Lipoprotein(a) — it raises your risk of having a heart-related event or getting cardiovascular disease, but it's hereditary. And then for dementia — this is a really exciting part, at least in the US. We now have a predictable way of picking up on mild cognitive impairment and picking up on these Alzheimer's hallmarks. Tau protein, specifically pTau-217, it's called on blood work, and amyloid beta. We can now pick up on this with 90% accuracy of a PET scan.
Brain performance drills: the Stroop test and tennis ball exercises
Steven Bartlett: What are those cards over there?
Louisa Nicola: These are here to test your processing speed. Your brain processes visual information 15 times faster than written words. So this is going to test your brain function. What I want you to do is you're going to see the colour. I want you to actually say the colour of the card, not the word.
Steven Bartlett: Okay. Let me just program my brain. Say the colour, not the word. Are you ready? Green, orange, yellow, green, orange, green, orange, yellow, pink, orange, green.
Louisa Nicola: Now let's do the reverse. I want you to say the words.
Steven Bartlett: Yellow, blue, green, black, purple, brown.
Louisa Nicola: Okay, so you're good.
The exercise then continues with a producer named Jack joining in, who also completes the colour-word test. Louisa then introduces a more demanding drill using a tennis ball and an eye patch.
Louisa Nicola: This actually involves us standing up and using a tennis ball. We're going to train your visual cortex, which sits at the back here in the occipital lobe. We're going to train your processing speed, your reaction time, your hand-eye coordination. One of the best physical exercises you can do is actually hand-eye coordination drills — tennis, racket sports. But I'm going to show you what 5 minutes a day can do for your cognitive reserve and your brain performance just using a tennis ball and an eye patch.
First things first, I'm going to give you this tennis ball. For the whole time, I want you to throw the ball with an overhand grip. Throw it with the right arm and catch with the right arm. Now throw with the right and catch with the left and alternate. We're engaging almost all the executive functions. You should be able to do this for a minute.
Now we're going to make it even harder. We're going to put an eye patch on you, which is really going to block out like 50% of the vision.
Steven Bartlett: Okay. Which eye?
Louisa Nicola: Any eye.
Steven Bartlett: Let's do the left one. Wow. This feels significantly harder.
Louisa Nicola: Let's go. Now alternate — left hand, right hand. You're training your visual system to work under load and under stress.
Steven Bartlett: This feels really hard.
Louisa Nicola: And then to make it even harder — stand on your right foot. Standing on one leg is now engaging the cerebellum. We're getting spatial awareness.
After Louisa demonstrates the drill herself with the eye patch on, the conversation returns to the neuroscience behind the exercise.
Steven Bartlett: So what is this doing?
Louisa Nicola: This is engaging executive functions, processing speed, hand-eye coordination.
Steven Bartlett: And you did this with NBA players.
Louisa Nicola: I did this with NBA players to improve their executive functions and decrease their reaction time.
Steven Bartlett: And this will change my brain if I do this frequently.
Louisa Nicola: Not just that, but you're also improving cognitive reserve. You're building new connections between the brain cells. You're strengthening neural networks.
The anterior mid-cingulate cortex: the neuroscience of willpower
Steven Bartlett: So doing hard things is what is going to improve brain function over the lifespan. Doing hard things tells your brain that you can do hard things. Have you ever heard of this brain area called the anterior mid-cingulate cortex?
Louisa Nicola: Yes, I have.
Steven Bartlett: What do you know about it?
Louisa Nicola: I'll let you say it.
Steven Bartlett: Well, it's shown that it's larger in what we call superagers — people who age really well and who can withhold a lot of cognitive capacity. And it's really profound in people who can diet well. It gets bigger when we do hard things. When we do really hard things, this area in the brain gets bigger. And basically what that is — it's reserve for when life gets hard. It tells your brain that no matter what happens, no matter what event comes my way, I have the ability to go in, welcome it, and push through it no matter how hard it's going to be. When you give up or when you don't do hard things, this little area doesn't grow. It doesn't get bigger. So doing these neural-activating drills that we just did, going to the gym and pushing well above your threshold — that's going to help grow this little area of the brain.
Louisa Nicola: And they call this the willpower muscle. This is why I think that when people go out to set their goals during the year and they say, "I'm going to lose 20 pounds, I'm just going to increase my willpower" — I think it's not willpower, it's neurobiology.
Steven Bartlett: I think it was Andrew Huberman who said — either to me or publicly — that he thinks it's one of the most fascinating or important discoveries of the last century.
Louisa Nicola: Of course. Think about how we're living our lives. We're punishing ourselves for not being able to read a book, for not being able to pay attention. How many people are now self-diagnosing themselves with ADHD, low attention spans, and they're blaming it on environment, blaming it on circumstances, when they should be blaming it on neurobiology and their brain state.
This area of the brain — if you can push it — this is why these superagers seem to have —
Steven Bartlett: What's a superager?
Louisa Nicola: A superager is somebody who is aging well. They're going through life with low cardiovascular disease. They've maintained their cognitive functions. They're at the age of 80 or 90 with a VO2 max profile of maybe a 50 or 60-year-old. So they're aging quite well biologically. These superagers have many different facets to them, and one of them is a larger mid-cingulate cortex.
Conversely, the AMCC — anterior mid-cingulate cortex — shrinks in people who live sedentary lives or avoid challenges. It literally atrophies if you play it safe in life too often. Growth only occurs during resistance. If you love taking ice baths and you take one, your AMCC doesn't change. If you hate the cold but force yourself to do it anyway, the AMCC grows.
Steven Bartlett: Scientists now view the AMCC as the seat of the will to live. Its size and activity level are strong predictors of how long an individual will survive after a major setback in their life — whether it's a health setback or a surgery.
Louisa Nicola: There's something really philosophical about that as well. It really dates back to how the Stoics lived their life, especially Marcus Aurelius, with being able to push through hard times. Little did they know that it was this little area in the brain.
Steven Bartlett: I was telling the story the other day of Roosevelt and what happened in his life as a young man when he came home one day on Valentine's Day and found that his mother and his wife — who had just had his newborn baby — had both died, one upstairs, one downstairs. He went off to the Badlands for two to four years. The Badlands in America were just this horrific natural place where he'd get up at 4:00 a.m. and ride horses in the freezing cold, where the horses would literally die standing still because it was so horrific. He did that for two years to deal with the grief. But when he came back to New York City, all of his friends said he was just a completely different man. And what we now know from a neuroscience perspective is that he didn't just build his muscles — he literally rewired his brain. He went on to become the youngest US president of all time. He got shot during a speech and carried on doing the speech. He led the charge in various wars. He won the Nobel Prize. And they point at those two years in the Badlands and say that forged not just the man, but his brain, his AMCC.
The studies also show that athletes consistently show much larger AMCC volume. And studies show that individuals struggling with obesity often have smaller AMCCs — but it begins to grow the moment they start a successful, challenging dietary or exercise intervention. That word "challenging" — because when you place stimulus upon a system, it adapts and grows. And that is neurobiology at its most fundamental.
This is why we get the breakdown of these synapses. This is why we go from 5,000 to 10,000 connections to 2,000 or no connections. These dendritic spines end up breaking down because we don't do the hard thing. And I also think, being deep-rooted in neurobiology, you can see that everything is cause and effect and it's a cycle. If you don't do the hard thing, you don't grow the AMCC. You don't grow the AMCC, you don't do the hard thing again. And it's just this loop — which is why so many New Year's resolutions end by February 1st. It's why we have the obesity epidemic. It's largely why I think we've got a crisis of people not being able to meet their goals.
Louisa Nicola: I'm just fascinated from an evolutionary perspective as to why we needed one and why it wasn't just always big.
Steven Bartlett: In the pursuit of hunting and going out and hunting for food sources, being motivated to do that in a near-starvation state when times were tough — and so when times got easier, we didn't need it as much. We could conserve our energy and scale down our willpower when times were good.
Louisa Nicola: It's interesting that you say that, because this brings up the whole brain rot and AI era. In 2024, the Oxford Dictionary named "brain rot" the word of the year. And it plays into evolution and what's happening with this AMCC — we're just scrolling through mindless information every day, training our brain to get these small dopamine hits, these small rewards from doing absolutely nothing.
Steven Bartlett: What do you think of these chatbots that everybody's using at the moment to write for them and think for them?
Louisa Nicola: I think it's on the spectrum of being so incredible but being so detrimentally harmful. I know this with myself. I did my master's in mathematics, and I was able — Steven — the trigonometry and pure calculus that I could do back then with just my head and a pen was fascinating. Now I'm going out and calculating the 20% tip on my bill using ChatGPT. How dumb am I actually getting? So I think it's both good and bad. I think the rate of decline we're seeing in people reading books and exercising their brain is declining. And our ability to think and use our cognition is declining.
Louisa's personal story: her grandmother, her obsession, and the cost of her career
Steven Bartlett: Louisa, I've waited a long time to ask you one particular question, which I think is very important. You're clearly very passionate about this stuff — one might say pretty obsessed. Why?
Louisa Nicola: We are living in a society that doesn't allow women to ask for what they want. We're living in a society that doesn't allow women to ask for what they need. And when this happens, it results in 70% of all Alzheimer's disease cases being women. It results in 80% of all autoimmune diseases being female. And these are largely preventable diseases.
When I ask why, and I hear that women are wildly misrepresented in academic literature, when I see women who downplay their symptoms or they're too scared to ask their doctor for advice, or they're ashamed of some of their symptoms — I get angry and I get passionate. And it reminds me of my grandmother. Her name was Louisa.
Steven Bartlett: You're named after her.
Louisa Nicola: I was named after her. Yes. And we spent every day together. And I'm getting emotional now because I remember her. She sadly died of ovarian cancer that went to pancreatic cancer. And she never asked for what she wanted. She never asked for what she needed, which was help. She didn't understand her symptoms. She didn't go to the doctor when she needed to, because she was just more inclined to look after the family and look after the household.
When the time came that she was given her diagnosis, I was sitting there with her. It was at home and the doctor came — she did a house call. My grandmother looked at her. She hardly spoke that much English, and she said, "Please, is there something I can do? I don't want to die." And the doctor said, "I'm sorry, there's nothing you can do."
I spent every day with her in the hospital. And I think about that — it's been almost 20 years now — but I think about that moment and I kick myself thinking, why didn't we get her a scan? She told us several times that her stomach was hurting. She told us several times that she felt pain. She hid her symptoms. She hardly ever ate at one point and we never stopped to think about why, and she never stopped to think about why.
So I think about her every day. And then I think about my mother too — these women, first generation, we migrated to Australia from a country called Cyprus. They've just put themselves second and they look after the family. And I can't stand that. When I see women coming in as patients or caregivers, I think to myself, do you not know that there is something for you to do? And most women don't.
And I can't believe the amount of money that we are spending going towards putting us on rockets to go to Mars, but we haven't yet found a cure for this disease that is largely preventable. It's just not okay with me.
Steven Bartlett: The emotion is still very present in your face even though it was so long ago.
Louisa Nicola: It was so long ago. I mean, I was very close to her. I'm very close with my mother — I check in with her two, three times a day. And I just don't think it's fair. I think women deserve the truth. They've been lied to. They've been underrepresented. And we need to change that.
With Louisa, your grandmother — what are those range of emotions that have turned into this incredible fire?
Louisa Nicola: Anger. Anger is one of the emotions. Anger at a society that places women to be everything — a mother, a caregiver, to go to work, to represent the family. Women represent 51% of the total population. And then it becomes political — because you think about healthcare. Healthcare should be accessible to everybody, but it seems as though, especially in this country, healthcare is only really accessible by those with a high socioeconomic status. And I'm not okay with that. So it does become political, even though a woman in need is apolitical. And my grandmother was apolitical, and her needs just were not met.
Anger, frustration at the system, frustration at the fact that we still have only 4% of women taking hormone replacement therapy in fear that they're going to get breast cancer — utterly frustrated at the cycles of administration who vouched to help you. You look to your government and your administration to guide you, and when you have Secretary Kennedy in 2014 go on national television and say, "Vaccines are totally safe. I had all my kids vaccinated. They've eradicated some of the most deadly diseases that have plagued this world. Vaccines are so safe" — to fast forward to 2025 saying vaccines are so unsafe, do not trust your medical doctor, you need to take your health into your own hands — you start to lose trust. And it's not that we're uninformed. It's the fact that we are confused.
You've got women here who don't even know how to get on the internet or order a blood test. You're expecting them to take their health into their own hands. So it upsets me that you see women who are so vulnerable being sold a vaccine lie which could potentially save them or their child from getting the flu, hepatitis B, meningitis — which was just eradicated from the vaccine schedule. I am a scientist. This is not propaganda. This is not ideology. This is just women who deserve to be treated better.
Steven Bartlett: You're 36. Louisa passed away when you were how old?
Louisa Nicola: Probably 18 at the time.
Steven Bartlett: You were 18 when she got the diagnosis.
Louisa Nicola: Around 18, 19. It was very fast — within a two-month time frame. Not even.
Steven Bartlett: And had she not got that diagnosis and had you not sat there and watched her ask that doctor if there's something she could do — do you think your career would have taken this course?
Louisa Nicola: I became utterly obsessed with disease management. But when I first saw a human brain, I was 21. I was in a lab and we had to go into a cadaver lab. I saw a brain being harvested from a body that was donated, and I stayed back that day. I helped in the pathology lab, and when I saw that brain, I knew that I wanted to dedicate my life to it. So ever since then I've been in neuroscience, and it's where I feel most alive.
Steven Bartlett: Why did you want to dedicate your life to it?
Louisa Nicola: Because when you know what the brain is — that it is responsible for the life that we have, and you can use it for your advantage to overcome any obstacle that comes your way — you become obsessed with understanding it. Metacognition is thinking about your thoughts, and every day if you can think about why you think about the things you think about, you can challenge yourself to overcome any adversity.
Steven Bartlett: Is there a cost to your obsession and your passion?
Louisa Nicola: Yes.
Steven Bartlett: What's the cost?
Louisa Nicola: I moved away from my family to be surrounded by the greatest neurosurgeons in the world, which I am, and I'm very thankful for that. I moved away from a population of 22 million to come to the hardest city in the world.
Steven Bartlett: New York.
Louisa Nicola: New York City.
Steven Bartlett: Are you still paying a cost?
Louisa Nicola: I'm still paying a cost. My health pays a cost. I've missed family events, traveling for my career. But I wouldn't have it any other way, because the people that I've met have forged the way for me to live the life that I want. I'm surrounded by incredible thought leaders in health and medicine.
Steven Bartlett: So what is success to you then at the deepest possible level? We meet again in 10 years time. You say your life has been a success. What does that mean? What happened?
Louisa Nicola: Being able to control my brain states.
Steven Bartlett: Being able to control your brain states.
Louisa Nicola: I think that the ultimate form of success and high performance — being able to perform at your peak — is being able to go from brain state to brain state and then be able to recover.
Steven Bartlett: What do you mean by brain state?
Louisa Nicola: Meaning being able to get switched on when you need to be switched on and invite the neurotransmitters involved in that — norepinephrine, adrenaline, dopamine — but not having that in constant overdrive, and being able to know when to switch off. I think that is what high performance is. The book that changed my mind on that was Flow by Mihaly Csikszentmihalyi, which speaks about the flow state. Being able to know how to separate yourself in these states.
Steven Bartlett: Any goals outside of your professional life?
Louisa Nicola: Kids, family, life. Love kids, family. Yeah, definitely.
Steven Bartlett: It's tough, isn't it?
Louisa Nicola: It's tough. I was saying earlier to my friend that I kind of just thought the minute I wanted to have kids, they would just appear. But it's not so simple.
Steven Bartlett: That's what I thought too, until I realized — oh, but I'm the woman. I actually have to bear the children as well.
Louisa Nicola: Which is a big sacrifice and an honor. It's an honor and a privilege and a sacrifice that I think everybody — yeah, I definitely want.
Steven Bartlett: Are you hopeful for all of your professional endeavors?
Louisa Nicola: Yes.
Steven Bartlett: You are hopeful. Do you think we're going to move in a good direction as a society as it relates to Alzheimer's?
Louisa Nicola: Yes, I am hopeful for that. I'm hopeful for the message that I'm getting across. I think social media is providing the platform for free education and for people to understand that they have agency over their brains. I'm not hopeful for anybody saving us or coming in and giving us an easy way forward.
Steven Bartlett: Do you ever have days where you wish you were less obsessed with your craft? Has there ever been a day where you're like, I wish I was just a little bit less captivated by this?
Louisa Nicola: Sometimes I do. Yeah. I think if I didn't, I'd probably be back home in Australia living an average person's life. Not saying that that's a bad thing — I'm just saying maybe I would have done my life differently.
Steven Bartlett: I have days like that where I think — obviously the obsessed brain is the one making this decision, so it's quite difficult to detach. But if you put a knob in front of me and I could just turn it down just a little bit, would I? My obsessed brain is like, "Turn it up." But I do wonder sometimes if I would be happier overall if I could just turn it down a little bit.
Louisa Nicola: But isn't the whole point of life to know thyself and be in pursuit of something bigger and better?
Steven Bartlett: Yeah, it is. But I just sometimes worry about what I'm sacrificing, and whether at some point — when I'm on my deathbed at 80 years old — I'm going to look back and say, "Actually, I made a bad trade."
Louisa Nicola: Well, exactly. And we're never going to know that. I think about that often. I know you think about that often — what would you regret today not having done if the world came to a collapse tomorrow?
Steven Bartlett: I think it would be making more memories with people I love. I think that's one of the big ones.
Louisa Nicola: Did you hear what you just said? Making more memories. And imagine losing those. Imagine a life full of creating these experiences and these memories, to have them being taken away from you. To not being able to recognize your wife, your kids, and looking in the mirror and not being able to recognize yourself.
Steven Bartlett: That's why Alzheimer's is just such a disgusting, sinister, horrific thing. It's just the most heartbreaking thing — to lose someone while they're still alive.
Louisa Nicola: Yeah. And to lose yourself. We've got this one woman who looks in the mirror and she says, "Who's that?"
Steven Bartlett: Really?
Louisa Nicola: Yeah. And it's sad, because two years ago she knew who I was, and now she asks, "Are you my daughter?" And when you're confronted with that every single day, it gets you thinking. You don't live a normal life. You don't live an average life, because you do think about every facet of medicine. You think about history. You think about diseases. And then you think about life and the people that you spend the most time with.
Closing question: What is God?
Steven Bartlett: We have a closing tradition where the last guest leaves a question for the next, not knowing who they're leaving it for. The question left for you is: what is God to you?
Louisa Nicola: God is that power that you feel and have faith in that you cannot see. The power that basically makes you feel like there is somebody there that has you and that is guiding you — that always has a path for you.
Steven Bartlett: You believe in God.
Louisa Nicola: Yes. I'm Christian. I'm Greek Orthodox.
Steven Bartlett: When you see the brain deteriorating in such a way and you think about this concept of prayer — asking God to help me with something — doesn't it feel pretty hopeless? I mean, it's the definition of hopelessness, watching your brain deteriorate. And I think some part of my struggles with religion since I was an 18-year-old — I came from a very religious family — was seeing injustice in the world. And there doesn't seem to be much greater injustice than watching someone's brain just deteriorate in front of their family.
Louisa Nicola: Yeah. Or somebody going through losing their child, and you start to think about God.
Steven Bartlett: People pray for — I can't find my keys, I want my football team to win. And I go, there's no point. If people praying for an Alzheimer's cure are having no luck, then maybe I should stop praying for Manchester United to win.
Louisa Nicola: If you understood the intricacies of how we were actually brought into this world — from the point of conception to the point of neural development, how a baby is formed and how precise everything has to be for you to come out the way you did — it is so beautiful and so miraculous and so rare. Even though there are billions of people in this world, you cannot just turn to biology anymore. You have to turn to something bigger.
And I used to — trust me, even as a Greek, as a Christian who's read the Bible — in my early 20s when I was getting into medicine and science, I was so gung-ho about: we're born in a body, we die in a body. But then when you get so deep into the literature of science and medicine and biology, it's hard to ignore God. It's hard to ignore that there is a higher power out there.
And why is it that there are chapels in hospitals? Because people want an alternative method of getting through whatever it is that they're going through — something that science and medicine cannot offer. And believing in something that is not there or something that hasn't occurred yet is having faith.
I work in neurosurgery, and some of the cases — you think this person's not coming out of here alive. And the fact that they do, and they preserve their cognitive functions, and they look next to normal after they've had a massive tumour resected — which is a true story from here. The tumour was going all along this one woman's face. She was 78 years old, who travelled here from France to have the tumour resected. How is it that she's walking and she's cognitively normal and she's not even on any medication the next day? How is that possible? Is it God? Is it just miraculous neurosurgeons? There are just some things that medicine can't answer.
Steven Bartlett: I agree with that. I don't think I'm arrogant enough to say that I know, and I'm curious, and I think I'll never know.
Louisa Nicola: Yeah.
Steven Bartlett: So I guess that's where we need to have faith.
Louisa Nicola: Yep.
Steven Bartlett: Louisa, thank you so much. It's very important that you do the work that you do, because it's people like yourself who are so passionate, so obsessed, and so good at communicating that help average people — who don't have access to the wisdom and the research and studies and information that you have — understand all of these things. And it's through this understanding that we can make better choices and preserve our life, preserve our brains. And if we preserve our brains, we preserve everything that matters.
Louisa Nicola: Correct. Thank you.
Steven Bartlett: Thank you for doing what you do and I appreciate your passion and dedication to it, because it's very, very important. I know it comes at a cost. So I feel obliged to tell you that as a normal person who isn't involved in your field, we're grateful.
Louisa Nicola: Thank you so much, Steven.