IBS, Stress and Gut Health with Professor John Cryan #20
Dr. Rangan Chatterjee interviews Professor John Cryan, a leading gut-brain axis researcher, on how our microbiome influences stress, mental health, and various physical conditions like IBS. They discuss the profound impact of gut microbes on overall well-being and practical ways to improve gut health.
Deep Dive Analysis
13 Topic Outline
Professor Cryan's Journey to Gut Microbiome Research
The Gut Microbiome's Role in Stress Response
Stress and Its Whole-Body Impact
Defining a Healthy Gut Microbiome
The Microbiome as an Intersection for Disease States
Understanding the Gut-Brain Axis
Diet, Microbiome, and Mental Health: The SMILES Trial
Transferring Depression via Microbiome in Animal Studies
Empowerment Through Microbiome Modification
Practical Advice from The Psychobiotic Revolution
Impact of Sugar, Sweeteners, and Drugs on the Microbiome
Optimizing Gut Health Despite Early Life Challenges
Personal Changes Based on Microbiome Research
6 Key Concepts
Microbiome
The collection of microorganisms (bacteria, fungi, viruses, etc.) that live inside us, along with their collective genetic material. It is essential for normal brain development and mounting an appropriate stress response.
Gut-Brain Axis
A communication system between the gut and the brain, known for hundreds of years, but increasingly understood through brain imaging. It involves signals from the gut influencing the brain and vice versa, crucial for maintaining bodily equilibrium and complex behaviors like food intake.
Psychobiotic
A targeted intervention of the microbiome, typically a probiotic or a prebiotic, designed to have beneficial effects on mental health. The term was coined to describe specific strains or substances that can influence the gut-brain axis positively.
Prebiotic
A dietary substance that acts as a 'fertilizer' to bolster the production and growth of beneficial microbes in the gut. Examples include inulin and various dietary fibers found in vegetables.
Enteric Nervous System
Often referred to as the 'second brain,' this system contains more neurons than the spinal cord and controls fundamental digestive processes like motility and permeability. It also signals directly to the brain and can be activated by microbes in the gut lumen.
Allostatic Load
The cumulative burden of chronic stress and life events on the body. The more load added to the system, the more it is weighed down and becomes vulnerable, affecting various bodily systems including the gut, cardiovascular system, and brain.
8 Questions Answered
Professor Cryan, a neuroscientist focused on stress, started collaborating on stress-related gut disorders like IBS. They found that early life stress affected the microbiome in animal models, leading them to investigate if the microbiome was mechanistically linked to stress and could be targeted for treatment.
The stress response is essential for dealing with threats and changes to homeostasis, sharpening cognition and diverting resources. However, chronic stress causes these systems to go out of kilter, affecting the entire body, including digestion, cardiovascular system, metabolic health, immune system, and brain health.
While still early days in research, there is emerging data suggesting the microbiome can help buffer resilience against stress. Studies have shown correlations between microbiome composition and stress responses in animals, and specific probiotics have been shown to blunt stress responses in healthy human volunteers.
In adulthood, a diverse microbiome, typically driven by a diverse diet, is considered a good indicator of health. However, there is no single 'normal' microbiome, and its ideal composition varies by individual and age, with less diversity seen in healthy infants.
Studies like the SMILES trial show that nutritional interventions, such as a modified Mediterranean diet, can support good mood and reduce depression symptoms. The microbiome is believed to be a key conduit in this effect, as beneficial microbes are supported by components like omega-3 fatty acids and polyphenols in such diets.
Practical steps include increasing dietary diversity, consuming fermented foods (kimchi, kefir, kombucha, yogurt, sauerkraut), increasing prebiotic fibers from green vegetables, minimizing processed foods, avoiding unnecessary antibiotics, supporting breastfeeding, having pets, ensuring good sleep, and engaging in aerobic exercise.
Artificial sweeteners are shown to be perniciously bad for microbes in animal studies, potentially worse than sugar itself. Additionally, at least 25% of commonly prescribed drugs, including some antipsychotics and antidepressants, can have negative effects on the microbiome, while some, like metformin, may have positive effects.
Yes, Professor Cryan is optimistic that individuals can still significantly optimize their gut health. Targeting the microbiome through diet and lifestyle can potentially override some 'miswiring' that may have occurred in early life, improving brain health and stress response.
14 Actionable Insights
1. Prioritize Diet Diversity
Aim for a diverse diet to promote a diverse microbiome, which is considered a key indicator of gut health in adulthood.
2. Increase Dietary Fiber Intake
Consume a high-fiber diet, including sources like inulin and green vegetables, as these act as prebiotics to bolster the production of beneficial microbes in the gut. Ensure you can tolerate it, especially if you have conditions like IBS.
3. Adopt a Mediterranean Diet
Follow a Mediterranean diet, as it contains components like omega-3 fatty acids and polyphenols that support a beneficial microbiome, which can positively affect mood.
4. Incorporate Fermented Foods
Increase consumption of fermented foods such as kimchi, kefir, kombucha, yogurt, and sauerkraut, as they have beneficial effects on the thriving bacteria in your gut.
5. Avoid Processed Foods
Minimize or avoid processed foods, as components like emulsifiers and sweeteners are known to negatively impact the microbiome.
6. Avoid Artificial Sweeteners
Avoid artificial sweeteners, as studies suggest they are perniciously bad for gut microbes, potentially even worse than sugar itself.
7. Avoid Emulsifiers
Avoid emulsifiers, often found in processed foods, as they have been shown to be detrimental to gut health.
8. Prioritize Good Sleep
Aim for good sleep, as there are emerging interactions between sleep, circadian rhythms, and the microbiome that are important for overall health.
9. Engage in Aerobic Exercise
Incorporate aerobic exercise into your routine, as it has been shown to have beneficial effects on the diversity of the microbiome.
10. Minimize Antibiotic Use
Reduce antibiotic use as much as possible, as they can have negative effects on the microbiome.
11. Blunt Stress with Bifidobacterium
Consider taking a specific bifidobacterium strain, as studies show it can blunt the acute stress response in healthy individuals. However, note that most strains will do nothing, and more research is needed.
12. Be Skeptical of Probiotics
Maintain skepticism about probiotic products on the market, as many lack scientific data; prioritize those with clear clinical evidence and understand why they work for you specifically.
13. Consider Getting a Pet
Having a pet has been shown in studies to increase the diversity of the microbiome, which is considered beneficial for gut health.
14. Support Breastfeeding
Support breastfeeding, as it is crucial for establishing a healthy microbiome trajectory in infants.
5 Key Quotes
We need the microbes for normal brain development and for mounting the appropriate stress response.
Professor John Cryan
The important thing about stress to remember is that stress doesn't just affect a few neurons within the hippocampus of the brain, it actually affects the entire body.
Professor John Cryan
We have to remember that the microbes were there first. And there has never been a time where our brain or our body has existed without signals coming from microbes.
Professor John Cryan
We don't need to know what's causing the changes in brain function to actually target it with potential bacteria.
Professor John Cryan
Your microbiome is something you have the potential to modify. And so that gives you, as an individual or as a patient, some level of empowerment in a way.
Professor John Cryan
1 Protocols
Gut Health Optimization Protocol
Professor John Cryan- Increase the diversity of your diet.
- Increase intake of fermented foods such as kimchi, kefir, kombucha, yogurts, and sauerkraut.
- Increase intake of prebiotics and fibers, especially from green vegetables and inulin-like substances.
- Avoid processed food, as components like emulsifiers and sweeteners can negatively impact the microbiome.
- Minimize antibiotic use as much as possible.
- Support breastfeeding, especially in early life, as it positively influences the microbiome's trajectory.
- Consider having a pet, which has been shown to increase microbiome diversity.
- Prioritize good sleep, as sleep, microbiome, and circadian rhythms are interconnected.
- Engage in aerobic exercise, which has beneficial effects on microbiome diversity.