95% of Alzheimer’s Cases Could Be Prevented Through Lifestyle. Neuroscientist Reveals the 3 Free Changes That Protect Your Brain

Louisa Nicola, a world-leading neuroscientist and brain health expert, is on a mission to change how we think about our brains.

She recently sat down to discuss the surprising truth about cognitive decline and dementia.

And what she revealed might completely transform how you approach your health today.

Because protecting your brain isn’t just about genetics—it’s about the choices you make every single day.

Your Brain Controls Everything You Are

Most people focus on losing weight, reducing visceral fat, or managing insulin resistance as they age. But Nicola argues we should start with the brain first.

“Our brain is responsible for everything that we are,” she explains. “Every thought you make, every decision you make, even every action, even down to the spouse that you choose is a result of how your brain is functioning.”

The problem? We can’t see our brain shrink or grow, so brain health isn’t deemed as “sexy” as a flat stomach or toned arms.

Yet the brain is the most vascular-rich, most powerful organ in your body. And because it takes decades to damage, most people don’t care about it until they’re in their 60s or 70s—when it may be too late.

What Actually Happens During Cognitive Decline

Understanding brain anatomy helps clarify what goes wrong during cognitive decline.

Your brain contains 86 billion neurons, and almost every neuron has 10,000 to 15,000 connections to other neurons. These connections communicate through synapses, creating a vast network that keeps you alive and functioning.

Over time—typically across 20 years—neurons begin losing these connections. The antennas coming off brain cells, called dendrites, start breaking off.

“You may go from a neuron having 10,000 connections to maybe having 2,000 connections and then to having no connections and then eventually cell death,” Nicola says.

This loss of synaptic connections is what we call cognitive decline. Memory impairment appears first, followed by reduced information processing speed. Eventually, the brain physically shrinks—not because cells die, but because connections disappear.

The 95% Solution: You Have More Power Than You Think

Here’s the revolutionary part: 95% of Alzheimer’s cases could have been prevented through lifestyle interventions.

“Alzheimer’s disease is driven by genes. Oh, my mom had it, so I’m going to get it. That’s absolutely not the case,” Nicola emphasizes.

Research on prevention rates shows variation, with most studies suggesting 30-40% of dementia cases are attributable to modifiable risk factors. While Nicola’s 95% figure is higher than current consensus estimates, the underlying message remains valid: lifestyle plays a substantial role in brain health outcomes.

Alzheimer’s affects 55 to 60 million people worldwide, with that number projected to triple by 2050. Two out of three cases are female.

But having genes that increase risk doesn’t guarantee you’ll develop the disease. You have tremendous agency to protect your brain and enable it to thrive as you age.

The Two Root Causes Destroying Your Brain

Nicola identifies two fundamental issues at the heart of brain decline: inflammation and energy deficiency.

Your brain constantly faces insults from air pollution, toxins, and poor diet. Over decades, these insults accumulate, leading to neurodegeneration.

Insulin Resistance: Type 3 Diabetes in the Brain

Insulin acts as a transporter in the brain, helping glucose enter cells for energy. When insulin resistance develops, brain cells can’t properly uptake glucose.

“If we have a brain that is not able to use this hormone correctly, it’s not able to transport glucose efficiently. Everything goes down from there. We have an energy problem,” Nicola explains.

Your brain represents only 2% of body weight but consumes 20% of total calories. When energy supply falters, brain cells begin dying off.

While Alzheimer’s disease shows metabolic changes in the brain, the “type 3 diabetes” label remains a research hypothesis rather than an established medical classification, according to current scientific literature.

Nicola recommends keeping hemoglobin A1C below three—a more aggressive target than the standard measure of below five.

The Worst Foods Destroying Your Brain

When asked about the worst foods people consume daily, Nicola doesn’t hesitate: refined sugar and refined carbohydrates.

Of course, because you’re putting your brain and your entire central nervous system in this sewer of inflammation.

Chronic inflammation shows up as headaches and brain fog initially. But sustained inflammatory states—which can be tested through high-sensitivity C-reactive protein (hs-CRP)—cause profound damage over time.

Foods to avoid include:

• High-fructose corn syrup
• Fruit juices
• Anything packaged or ultra-processed
• Refined carbohydrates

Nicola advocates for a plant-forward omnivore diet similar to the Mediterranean-DASH intervention (MIND diet), which includes moderate amounts of meat and fish alongside abundant plant foods.

“I love having red meat. I think that red meat is abundant in everything…it’s rich in B vitamins. It’s rich in carnitine,” she notes, emphasizing the importance of vitamin B12 for brain health.

Alcohol: No Safe Amount for Your Brain

Nicola acknowledges she “gets in trouble a lot” for this stance, but the evidence is clear: no amount of alcohol is good for the body.

When you ingest ethanol, your liver converts it to acetaldehyde—which is literally poison that kills brain cells.

A landmark study from the UK Biobank examined moderate drinkers (seven drinks weekly for women, 13-14 for men) using MRI and PET scans. Researchers discovered two alarming findings:

1. Reduced gray matter volume in the cortex responsible for thinking and motor control
2. White matter lesions in the deep brain tracks that transmit thoughts and speed

These white matter tracks are insulated by a fat layer called the myelin sheath. Lesions and thinning in this area accelerate cognitive decline.

While one glass of wine per week has shown no harmful effects in some research, Nicola advises thinking of your brain as having a “loading system.” If you’ve been stressed, eating poorly, or sleep-deprived, adding alcohol creates diminishing returns.

Ketones: Cleaner Fuel for Your Brain

While glucose is the brain’s primary fuel, beta-hydroxybutyrate ketones offer a more efficient alternative.

Ketones are especially beneficial for carriers of the APOE4 gene, which increases Alzheimer’s risk. These individuals utilize ketones more efficiently than glucose.

When I actually have exogenous ketones myself, I have lasting brain energy. For some reason my appetite is suppressed and I feel like I’ve got cleaner mental energy. It’s like having a coffee without all the jitters.

While ketogenic diets can produce ketones endogenously, achieving and maintaining ketosis is challenging. Even small amounts of carbohydrates—like one grape or a Coke Zero—can kick you out of ketosis.

Nicola recommends supplementing with exogenous ketones, specifically mentioning Ketone-IQ as a liquid form she uses during long workdays.

A notable study showed a glioblastoma tumor—the most aggressive brain cancer with near-zero survival rate—actually shrunk when the patient followed a ketogenic diet, demonstrating ketones’ powerful neuroprotective effects.

The Truth About Fats and Your Brain

Many people misunderstand which fats actually benefit the brain.

Dietary cholesterol cannot cross the blood-brain barrier. This means eating butter or saturated fat doesn’t directly nourish your brain the way many assume.

Instead, approximately 60% of brain lipids consist of DHA (docosahexaenoic acid), which comes from EPA and DHA found in fatty fish.

“If the brain is made of DHA then we can actually go through and think well am I having enough fatty fish in my diet? Is my omega-3 index high enough which it should be around 8% or more?” Nicola asks.

The average omega-3 index in the United States is 4% or less—far below optimal.

DHA performs several critical functions:

• Improves cell membrane fluidity around brain cells
• Downregulates inflammation as effectively as FDA-approved drugs
• Protects the blood-brain barrier’s tight junctions

To increase your omega-3 index from 5% to 6% requires approximately 2 grams of combined EPA and DHA daily for 6-12 months. Nicola personally takes 4 grams daily (2g DHA, 2g EPA).

Unfortunately, even fatty fish like salmon and mackerel may be stripped of nutrients depending on sourcing. Supplementation becomes essential.

Finding Quality Omega-3 Supplements

Supplements are largely unregulated. A study examining 75 popular omega-3 products found every single one exceeded acceptable oxidation levels—meaning they’d gone rancid.

Nicola recommends using the app SupCo (SUPCO), which independently tests brands and scores them 0-10 on quality, manufacturing, and oxidation levels.

Creatine: The Anti-Depressant Hiding in Your Supplement Cabinet

Creatine was long considered just a bodybuilding supplement. But extensive research reveals it’s one of the most important nutrients for brain health.

Your liver naturally produces about 2 grams of creatine daily, which helps with cellular energy metabolism in the mitochondria. But that’s not nearly enough.

Here’s the problem: 95% of creatine stores concentrate in muscle tissue, leaving only 5% for the brain. And creatine loses bioavailability when crossing the blood-brain barrier.

The new recommended dosage is 10-15 grams daily—double or triple the traditional 5-gram recommendation. This ensures muscles are saturated while leaving stores available for the brain.

Creatine as an Anti-Depressant

Clinical trials have produced stunning results. Researchers divided participants with clinical depression into two groups:

• Group one received standard SSRI anti-depressants (like Zoloft)
• Group two received creatine instead of their anti-depressants

After just one week, the creatine group experienced identical outcomes to those taking pharmaceutical anti-depressants.

We found out that creatine serves as just the same thing as an anti-depressant because of energy, brain energy metabolism.

Creatine is now being administered to neurosurgery patients because of its profound effects on brain energy and mental health.

Even eating meat doesn’t provide adequate creatine—100 grams of beef contains only 0.5 grams, and bioavailability is limited through digestion.

Exercise: The Most Foundational Elixir

Nicola becomes visibly emotional discussing exercise, calling it “the most foundational elixir to all cause mortality and especially Alzheimer’s disease.”

Her research shows that compound movement resistance training just twice weekly can reduce mild cognitive impairment risk by 32%.

MRI scans reveal that resistance training alone can actually change brain morphology, improving synaptogenesis and dendritic spine growth.

The Magic of Myokines

When you contract muscles under tension, they release muscle-based proteins called myokines. These cross the blood-brain barrier and perform remarkable functions:

• Improve executive function in the prefrontal cortex
• Amplify BDNF expression (brain-derived neurotrophic factor—essentially fertilizer for the brain)
• Reduce inflammation through interleukin-6, which becomes anti-inflammatory when released from muscle

BDNF promotes neuron growth and proliferation in the hippocampus—the seahorse-shaped structure responsible for memory formation that shrinks during Alzheimer’s. Exercise literally grows this brain region.

Nicola describes myokines as “a cocktail of pharmaceuticals that live in your muscles, and they can only be released during resistance training.”

Zone 5 Training: Reversing 20 Years of Heart Aging

While zone 2 cardio has become trendy, Nicola argues zone 5 training is far more critical—especially for women.

Sports cardiologist Ben Levine conducted a groundbreaking study on 50-year-olds, subjecting them to rigorous zone 4-5 training for two years. Using 3D heart imaging and MRIs, he discovered they reversed 20 years of age-related heart decline—effectively creating 30-year-old hearts.

Zone 5 training involves pushing to 90-95% of maximum heart rate. You only need 20-30 minutes weekly, performed in intervals.

The gold standard is the Norwegian 4×4 protocol (4 minutes hard, 4 minutes rest). But beginners can start with 1 minute on, 1 minute off, repeated 5-20 times.

This threshold training improves VO2 max—the strongest predictor of all-cause mortality.

Why Women Don’t Need as Much Zone 2

Zone 2 cardio increases mitochondrial density, which benefits men significantly. But women naturally possess more mitochondrial density than men.

“What we need…is zone 5 doing heavy resistance training and that’s all they need to do,” Nicola explains. “Zone 2 should be a supplement” for women—something to enjoy on weekends with family, not the primary focus.

Exercise and Cancer Prevention

Zone 5 exercise creates shear force as blood rapidly moves through vessels. Research shows this shear force can actually kill circulating tumor cells—cancer cells that break off from tumors and seek new places to lodge.

A study published in Nature demonstrated that myokines can inhibit prostate tumor growth because prostate cells have myokine receptors.

Combining zone 5 exercise with a ketogenic diet has even shown ability to shrink prostate cancer.

The Dangers of Being Sedentary

“Being sedentary is a disease. It’s almost equivalent to a pack a day smoker,” Nicola states bluntly.

Studies on hospital bed rest show just 10 days of immobility increases mortality risk tenfold. Sedentary behavior doesn’t just prevent muscle use—it affects mind, social interaction, and accelerates muscle mass loss.

Walking remains foundational. Aim for 7,500-8,000 steps daily, not the often-cited 10,000.

Additional Brain-Boosting Nutrients

Choline

Found abundantly in egg yolks, choline serves as a precursor to acetylcholine—the neurotransmitter needed for synapse creation.

Despite current choline deficiency being widespread, it doesn’t raise cholesterol and is phenomenal for fetal neural development.

Taurine

This vasodilator increases blood flow to the brain. It’s excellent consumed prior to exercise, which explains its inclusion in many pre-workout supplements.

Fasting and Autophagy: Context Matters

Fasting can trigger autophagy—the cellular “cleaning out” process beneficial for the brain. But Nicola emphasizes context, particularly for women.

A 16-hour fast may be appropriate for some. But females face unique considerations due to monthly menstruation and hormonal fluctuations.

Fasting is especially problematic for women trying to conceive. Even women with balanced hormones need to be cautious, as fasting can elevate cortisol.

“Would it kill a female who is 55 or 60 to do a one-day fast? Probably not,” Nicola notes. But women shouldn’t replicate male fasting protocols without considering hormonal impacts.

The key issue: most medical research has been conducted exclusively on men. Medications, supplements, and protocols are typically designed for male physiology.

Sleep: When Your Brain Takes Out the Trash

During deep slow-wave sleep, glial cells—the chief immunity cells in the brain—shrink in size. This allows cerebrospinal fluid to wash through the brain, clearing out amyloid beta.

Everyone has amyloid beta in their brain. It’s part of the innate immune system, released in response to threats. But when we don’t get adequate deep sleep, it accumulates outside cells and blocks dendritic communication—leading to cognitive decline.

Aim for 1-2 hours of deep sleep nightly. Factors that improve deep sleep include:

• Sleep regularity (same bedtime and wake time daily—more important than total sleep duration)
• Avoiding alcohol
• Not eating close to bedtime
• Eliminating sugar at night, which spikes glucose and insulin
• Managing stress to prevent sympathetic nervous system activation

REM sleep handles memory consolidation and emotional processing, while deep sleep provides complete brain and body reset.

The Three Non-Negotiables for Brain Longevity

When asked for her top three tips, Nicola doesn’t hesitate:

1. Exercise Daily

“Learn to love exercise. I don’t care how. Learn to love it and do it every single day,” she urges.

Movement protects both brain and body as you age. Make it non-negotiable.

2. Nutrition and Hydration

Get a proper diet free from ultra-processed foods and refined sugars. But don’t forget hydration—water and electrolytes are food for the brain.

3. Quality Relationships

This may surprise you, but the 80-year Harvard follow-up study revealed that brain quality is dictated by relationship quality.

If you can invest in social interactions that are going to feed your brain and feed your soul and make you actually feel safe, that’s going to do wonders for your brain as you age.

Engaging in conversations with people who challenge you politically, environmentally, or philosophically makes your brain think differently. This cognitive stress promotes growth and adaptation.

You Are Not Destined for Decline

Perhaps the most empowering message from Nicola’s work is this: you are not destined for cognitive decline.

Even if your mother had Alzheimer’s. Even if you carry the APOE4 gene. Even if you’re already experiencing brain fog or memory issues.

The interventions that protect your brain are remarkably simple—they’re what our ancestors did naturally. Walk daily. Lift heavy things. Sprint occasionally. Eat unprocessed foods. Sleep consistently. Connect with others.

Your brain is a 2-pound organ that controls everything you are. Every thought, every decision, every relationship.

It’s time to treat it like the irreplaceable treasure it is.

Sources

• Livingston et al., The Lancet (2020) – Dementia prevention: https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30367-6/fulltext
• Topiwala et al., Nature Communications (2022) – Alcohol and brain health: https://www.nature.com/articles/s41467-022-28735-5
• de la Monte & Wands, Journal of Alzheimer’s Disease (2008) – Type 3 diabetes concept: https://pubmed.ncbi.nlm.nih.gov/18997301/
• Hallsworth et al. on omega-3 oxidation (ConsumerLab): https://www.consumerlab.com/
• Liu et al., Journal of the International Society of Sports Nutrition (2018) – Creatine and depression: https://jissn.biomedcentral.com/
• Levine et al., Circulation (2018) – Exercise reversing cardiac aging: https://www.ahajournals.org/journal/circ
• Vaillant, Harvard Study of Adult Development: https://www.adultdevelopmentstudy.org/
• SupCo (supplement testing): https://www.supco.io/
• OmegaQuant (omega-3 testing): https://omegaquant.com/