The Diary Of A CEO with Steven Bartlett

The Microbiome Doctor: Doctors Were Wrong! The 3 Foods You Should Eat For Perfect Gut Health!

January 26, 2026

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  • Brain health issues like dementia, depression, and anxiety are fundamentally linked to gut health, challenging the traditional view of the brain as a separate organ. 
  • Inflammation, driven by diet and immune system responses (even from minor events like vaccines), is a critical underlying factor in many brain and mental health disorders. 
  • The eight rules for gut health, which include eating 30 different plants weekly and consuming fermented foods, are presented as crucial for overall physical and mental wellbeing. 
  • Time-restricted eating, particularly avoiding unhealthy late-night snacks, can improve gut lining integrity and microbial activity, though adherence is highly personalized. 
  • The ketogenic diet, while potentially offering profound cognitive benefits like mental clarity by switching brain energy from glucose to ketones, is difficult to sustain long-term and must be balanced against the need to maintain a healthy gut microbiome. 
  • Early life trauma and chronic stress can lead to permanently raised inflammation levels, linking physical and mental health issues across various diseases, and talk therapy can help reduce these inflammatory markers. 

Segments

AI and Business Finance
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(00:00:00)
  • Key Takeaway: NetSuite integrates AI into financial systems to automate tasks and provide actionable insights.
  • Summary: NetSuite by Oracle embeds AI throughout organizations for financial management, inventory, and HR in one platform. Its AI connector allows businesses to connect their chosen AI with company data to ask specific business questions. This integration makes AI smarter, automating routine tasks and cutting costs for over 43,000 businesses.
Jobber Streamlining Home Services
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(00:01:07)
  • Key Takeaway: Jobber centralizes paperwork for home service businesses, accelerating payment collection.
  • Summary: Jobber manages all paperwork, from quotes to payments, preventing loss of documentation for home service jobs. Businesses using Jobber report growing an average of 44% in their first year. Furthermore, they get paid four times faster compared to using checks.
Flossing and Dementia Risk
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(00:01:37)
  • Key Takeaway: Flossing can reduce the risk of dementia by nearly half.
  • Summary: Research indicates a significant link between oral health and brain health, specifically reducing dementia risk through flossing. This highlights the crucial connection between the gut/body and the brain, which has been overlooked for 40 years. The brain is influenced by signals from the rest of the body, including oral bacteria.
Professor Spector’s Background and Motivation
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(00:02:09)
  • Key Takeaway: Professor Tim Spector is motivated to reverse the dementia epidemic due to personal family experience.
  • Summary: Professor Tim Spector, a top-cited scientist, focuses on the gut’s role in physical/mental health and chronic disease prevention. His research is strongly motivated by his mother’s experience with dementia, leading him to investigate the brain-gut axis more deeply. He believes diet choices can dramatically improve health outcomes.
Dementia Prevalence and Types
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(00:04:09)
  • Key Takeaway: Dementia is increasing beyond demographic changes, and vascular dementia is a major type.
  • Summary: Dementia is increasing due to longer lifespans without corresponding health span increases, and also independently of demographic shifts. Steven Bartlett underwent dementia screening due to his mother’s condition and his own history of a mini-stroke. Vascular dementia, caused by clogged brain arteries, accounts for about one-third of all dementia cases.
Brain Health Paradigm Shift
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(00:09:21)
  • Key Takeaway: The brain is now understood as an organ deeply connected to the body via the gut, not a separate entity.
  • Summary: The speaker’s view shifted from seeing the brain as distinct (Cartesian view) to recognizing its deep connection with the body, particularly the gut. This realization stemmed from Zoe diet studies showing immediate improvements in mood and energy before physical changes occurred. Eighty percent of signals along the vagus nerve travel from the gut to the brain, emphasizing the gut’s informational dominance.
Diet’s Impact on Mood and Energy
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(00:12:54)
  • Key Takeaway: Poor diet, especially ultra-processed food and late-night snacking, directly causes low mood and fatigue.
  • Summary: Mood and energy levels are immediately improved when participants switch from bad diets to gut-friendly diets, often before they realize the link. Families on highly processed diets reported dramatically increased mood and energy after dietary transformation. This creates a vicious cycle where feeling bad leads to craving unhealthy food for a quick fix.
Stress, Immune System, and Depression
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(00:16:22)
  • Key Takeaway: Stress and immune system activation, rather than just chemical imbalance, drive depression.
  • Summary: Stress is increasingly viewed as a physiological event driving inflammation and affecting the immune system, which then signals the brain to change behavior. Post-vaccination depression observed in Zoe studies demonstrated how a minor immune shift can trigger illness behavior. Chronic depression may result from the immune system being constantly ’tickled’ by underlying inflammation.
Immune Basis of Brain Diseases
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(00:19:37)
  • Key Takeaway: Inflammation and metabolism control are crucial for preventing brain diseases like dementia and Parkinson’s.
  • Summary: The immune basis of mental and brain diseases is becoming paramount, as inflammation accelerates aging in the brain. Uncontrolled blood sugar (metabolism) is the number one risk factor for many brain conditions; Type 2 diabetes quadruples the likelihood of developing them. Genetic predisposition for brain diseases shows low heritability, suggesting environmental factors like inflammation are dominant.
Parkinson’s Disease Origin Theory
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(00:22:46)
  • Key Takeaway: Parkinson’s disease likely originates in the gut via misfolded proteins traveling up the vagus nerve.
  • Summary: Epidemiological data shows 90% of future Parkinson’s patients had gut problems ten years prior to diagnosis. The misfolded protein alpha-synuclein, which forms Lewy bodies in the brain, is also found misfolded in the gut tissue of these patients. The theory suggests these proteins travel slowly up the vagus nerve over a decade to cause the neurological disorder.
Eight Rules for Gut Health
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(00:26:16)
  • Key Takeaway: Gut health rules focus on mindful eating, plant diversity, fermented foods, and intermittent fasting.
  • Summary: The first rule is to be mindful of food choices, questioning quality and feeling before consumption. The second key rule is eating 30 different types of plants weekly to fertilize diverse gut microbes. Rule three is consuming three portions of fermented foods daily to reduce blood inflammation levels.
Gut Microbes and Plant Diversity
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(00:27:22)
  • Key Takeaway: Gut microbes are specialized, requiring diverse plant matter (fertilizer) to thrive and produce beneficial chemicals.
  • Summary: The gut contains trillions of microbes that act as mini-pharmacies, with thousands of species specialized to eat specific foods, like one bug that only consumes coffee. Feeding this diversity with 30 different plants per week expands the beneficial microbial population. A larger, healthier microbial community outcompetes ‘bad bugs’ that thrive on processed foods.
Coffee Consumption Benefits
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(00:30:15)
  • Key Takeaway: Epidemiological data suggests drinking 2-5 cups of coffee daily reduces heart disease risk by 25%.
  • Summary: Multiple long-term studies show that moderate coffee consumption is associated with a 25% reduction in heart disease risk. While some individuals react poorly to caffeine, the general population benefits from compounds like the microbe Laucinobacter that break down coffee. This reverses previous demonization of coffee regarding heart health.
Prebiotics vs. Probiotics Efficacy
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(00:36:06)
  • Key Takeaway: Prebiotics (fertilizer) are significantly more powerful than probiotics (seeds) for improving the gut microbiome composition.
  • Summary: A study comparing Zoe’s Daily 30 prebiotic blend against a standard probiotic showed the prebiotic changed about 40 key microbes, while the probiotic only affected 4 or 5. The thinking has shifted: probiotics likely ’tickle’ the immune system in the small intestine rather than seeding the large intestine. Prebiotics provide diverse food sources for existing microbes to flourish.
Anatomy of the Gut System
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(00:37:36)
  • Key Takeaway: The large intestine houses 99% of gut microbes, which convert fiber into beneficial short-chain fatty acids.
  • Summary: The small intestine is the longest part of the gut, responsible for nutrient absorption across a surface area equivalent to several tennis courts. The large intestine (colon) is where most gut microbes reside, feeding primarily on fiber to produce beneficial chemicals like short-chain fatty acids. Seventy percent of the body’s immune cells and the enteric nervous system (the second brain) are located within the gut.
Oral Microbiome and Dementia Link
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(00:41:06)
  • Key Takeaway: Poor oral hygiene, specifically not flossing, doubles the risk of dementia by allowing inflammatory microbes to reach the brain.
  • Summary: The mouth is the second largest reservoir of microbes after the gut. Inflammation caused by plaque allows ’nasty microbes’ to thrive, which then appear to pass from the mouth into the brain. This triggers brain inflammation, directly increasing dementia risk.
Human Origins and Microbes
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(00:42:07)
  • Key Takeaway: Humans evolved from microbes, and mitochondria within our cells are remnants of energy-producing microbes that fused with ancestral cells.
  • Summary: The human body is composed of millions of organisms, stemming from the initial fusion of single-celled microbes that formed multicellular life. The gut tube forms first in embryonic development, designed to train the immune system via microbes. Mitochondria, crucial for energy, metabolism, and fighting inflammation, originated from energy-producing microbes incorporated into our cells long ago.
Gut Health Rule 3: Fermented Foods
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(00:49:46)
  • Key Takeaway: Consuming three daily portions of fermented foods significantly reduces blood inflammation levels by up to 25%.
  • Summary: A Stanford study showed that five daily portions of ferments reduced blood inflammation markers by 25% over a month compared to a high-fiber diet. Fermented foods like yogurt, cheese (non-American), kefir, kraut, and kimchi are chemically transformed by microbes to be more nutritious. Even dead ferments (post-biotics) appear to benefit the host by signaling the immune system to calm down.
Gut Health Rule 4: Pivot Protein Sources
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(00:57:34)
  • Key Takeaway: Focus on plant-based proteins like legumes and whole grains to ensure adequate fiber intake for gut microbes.
  • Summary: Most people already consume sufficient protein, often focusing too heavily on meat and eggs. Shifting protein intake towards beans, legumes, quinoa, and barley provides necessary fiber, as 90% of people are fiber deficient. Starving gut microbes by relying only on protein drinks prevents them from thriving.
Gut Health Rule 5: Quality Over Calories
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(00:58:33)
  • Key Takeaway: Assessing food by calories is ineffective; focus instead on high-quality, minimally processed whole foods.
  • Summary: Calorie-restricted diets generally fail long-term because they increase hunger signals, which are the main driver of obesity. High-quality foods retain their original structure and nutrients, supporting gut health better than low-calorie alternatives. Avoiding high-risk processed foods is crucial because their additives disrupt gut microbes that have never encountered these artificial substances.
Identifying High-Risk Processed Foods
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(01:01:41)
  • Key Takeaway: Foods are categorized by risk (zero, mild, moderate, high) based on additives, hyper-palatability, and lack of natural structure.
  • Summary: Highly processed foods contain emulsifiers, preservatives, and artificial sweeteners that damage gut microbes. These foods are often hyper-palatable, designed to make consumers overeat by about 25% because they require minimal chewing. White bread is cited as a high-risk example that provides a temporary energy kick but fails to satisfy hunger long-term.
Gluten Intolerance Misdiagnosis
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(01:04:35)
  • Key Takeaway: Most people who believe they are gluten intolerant are reacting to other additives in processed bread products, not gluten itself.
  • Summary: Up to 30% of people report issues with gluten, but only about 1% strictly require avoidance. Symptoms like gas or stomach pain from cheap sandwiches are often caused by emulsifiers, colorants, or poor-quality fillings. Healthier, whole-grain sourdoughs or rye breads are better tolerated because they lack these disruptive additives.
Gut Health Rule 6: Polyphenols and Color
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(01:08:14)
  • Key Takeaway: Eating colorful foods rich in polyphenols fuels beneficial gut microbes, while bitterness is also a sign of health.
  • Summary: Natural colors in foods like berries, purple cabbage, and dark chocolate indicate the presence of polyphenols, which act as fuel for gut microbes. These polyphenols enable microbes to produce beneficial short-chain fatty acids, improving the immune system. Bitterness, found in extra virgin olive oil and coffee, is another natural signal indicating high health benefits.
Gut Health Rule 8: Time-Restricted Eating
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(01:09:48)
  • Key Takeaway: A 12 to 14-hour overnight fast allows the gut to recover, improves the lining, and supports microbial cleanup.
  • Summary: Time-restricted eating acts like a good night’s sleep for the gut, promoting metabolic advantages and reducing gut lining permeability. Avoiding late-night snacking is crucial for gut and brain health, as it allows the gut’s cleaning team to operate. While difficult for some, even avoiding unhealthy late-night snacks provides a significant positive impact.
Time-Restricted Eating Personalization
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(01:08:12)
  • Key Takeaway: Avoiding late-night snacking significantly impacts gut and brain health, even if strict time-restricted eating protocols are not fully maintained.
  • Summary: Restricting eating time to 10 hours shows metabolic advantages and improves the gut lining, reducing leakage and inflammation. A ZOE study on 14-hour time-restricted eating showed one-third of participants could not adhere due to constant hunger. Even for those who find strict adherence tough, avoiding unhealthy late-night snacks provides a major benefit for gut and brain health.
Sponsor Plug: Ketone IQ
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(01:11:39)
  • Key Takeaway: Ketone IQ is described as a game-changer for focus and energy levels by a significant portion of the speaker’s team.
  • Summary: The speaker became a co-owner of the company producing Ketone IQ after experiencing significant positive effects on focus, energy, and productivity. This product is currently a sponsor of The Diary Of A CEO podcast. Listeners can receive a discount by visiting the specified URL.
Sponsor Plug: Conversation Cards
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(01:12:39)
  • Key Takeaway: Conversation Cards are designed to foster deep connection by turning guest-left questions into interactive discussion prompts.
  • Summary: The Conversation Cards were created to facilitate the deep, connected conversations often experienced on the show. The new edition includes a limited-edition gold card featuring an exclusive question from the host, Steven Bartlett. These cards aim to enhance social connection, which is vital for wellbeing.
Keto Diet and Brain Metabolism
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(01:13:30)
  • Key Takeaway: The ketogenic diet is highly effective for drug-resistant childhood epilepsy by switching the brain’s primary energy source from glucose to ketone bodies.
  • Summary: The speaker has become ‘keto-curious’ due to research on brain metabolism, noting keto’s established role in treating drug-resistant epilepsy. This diet forces the brain to switch to ketone bodies for energy after glucose reserves are depleted, acting as a ‘reboot’ mechanism. While anecdotal evidence suggests benefits for other mental health issues, sufficient clinical evidence is currently lacking.
Cycling Keto for Cravings Control
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(01:16:15)
  • Key Takeaway: Cycling in and out of ketosis can temporarily dampen food cravings, helping individuals reset and regain control over unhealthy eating spirals.
  • Summary: Keto dampens ‘food noise’ and cravings for junk food, allowing for a reset period of several weeks. Cycling the diet helps break downward spirals caused by stress, poor sleep, or travel leading to sugar consumption. Even short periods of keto can lead to healthier eating habits in the weeks following cessation.
Microplastics in Blood Findings
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(01:20:01)
  • Key Takeaway: The speaker’s blood scan revealed high levels of smaller environmental microplastics, likely inhaled from decades of living and cycling in London.
  • Summary: The speaker was found to have microplastics in the highest 20% for environmental types, which were primarily the smaller particles inhaled through the lungs. Avoiding plastic containers and bottles is a proactive step, though clinical trials on removing existing microplastics are not yet convincing. Other environmental factors like pesticides may pose a greater immediate concern.
GLP-1 Drugs: Benefits and Concerns
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(01:24:17)
  • Key Takeaway: GLP-1 drugs will transform obesity treatment but require mandatory lifestyle education during the window of suppressed hunger to prevent yo-yo dieting.
  • Summary: These drugs are expected to revolutionize medicine and obesity treatment, especially as pills become cheaper and more accessible. A major concern is that many users take them without supervision or dietary advice, leading to failure when they stop the medication. The drugs appear brain-protective, potentially reducing dementia risk and addictions, but long-term effects on personality traits like entrepreneurial drive need monitoring.
Sauna and Socializing for Brain Health
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(01:27:09)
  • Key Takeaway: Regular sauna use acts as a workout for blood vessels, and maintaining a core group of friends is crucial for mental and brain health by combating loneliness.
  • Summary: The speaker enjoys a sauna routine twice a week, sometimes followed by a cold plunge, viewing it as beneficial exercise for the body and brain. The happiest, longest-lived populations consistently have strong social lives, emphasizing that loneliness is detrimental to brain health. Maintaining regular contact with a key group of friends is highly important.
Trauma’s Physiological Impact
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(01:28:45)
  • Key Takeaway: Early life emotional, physical, or sexual trauma is strongly correlated with a higher likelihood of developing brain diseases later in life due to permanently raised immune system inflammation.
  • Summary: Studies show that trauma or stress in early life can trigger a permanent elevation in the immune system’s inflammatory response, meaning the body’s stress thermostat does not return to baseline. This links early adverse experiences to conditions like chronic pain, IBS, epilepsy, and schizophrenia. Talk therapy has been shown to reduce these inflammation levels, suggesting shared pathways for treatment.
Food as Powerful Medicine
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(01:32:14)
  • Key Takeaway: The ability to dramatically improve health through serious, experimental food choices is the most exciting prospect, but requires environmental changes to support discipline.
  • Summary: The speaker is driven by the dramatic positive effects seen when people treat food with the seriousness of medicine. Overcoming the ultra-processed food environment requires ’tricks’ and proactive environmental changes, similar to how smoking environments were regulated. Changing the first meal of the day is often key to establishing new, healthier habits.
Sponsor Plug: NetSuite AI Integration
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(01:40:04)
  • Key Takeaway: NetSuite’s AI cloud financial system embeds AI throughout business operations to automate tasks and deliver actionable insights by connecting all financial and operational data.
  • Summary: NetSuite is the leading AI cloud financial system, integrating accounting, inventory, and HR data into one platform. Its AI connector allows businesses to use their preferred AI tools with their connected data for smarter insights. Over 43,000 businesses are using NetSuite to future-proof operations.