Raja Dhir: Gut Health, the Microbiome, and How Fiber Protects Your Health on The Genius Life with Max Lugavere

Check out The Genius Life with Max Lugavere Episode Page & Show Notes

Key Takeaways

  • The microbiome is the community of organisms (viruses, bacteria, and fungi) that live in and on the human body
    • It consists of the gut microbiome, the skin microbiome, and the mouth microbiome (to name a few)
  • There are many issues with microbiome diagnostic tests – don’t infer too much from the results
  • A diverse microbiome isn’t always a better microbiome – there are many contributing factors to overall microbiome health
  • From a microbiome perspective, it’s best to avoid artificial sweeteners like stevia and aspartame
  • The number one predictor of a diverse and resilient microbiome is the consumption of over 30 different kinds of fruits and vegetables in any given week
    • “Diversity of diet is good for diversity of gut”Raja Dhir
    • A good predictor of an unhealthy microbiome is the consumption of <10 different kinds of fruits/vegetables in a given week
  • If you eat whole food sources, you should have no need for a fiber supplement
  • “If there are risks of meat consumption, they can be attenuated by appropriately adjusting your vegetable intake”Raja Dhir
  • All fats are not created equal in the eyes of the microbiome
    • Avoid excess amounts of saturated fat
    • Eat more monounsaturated fats (the primary fat in extra virgin olive oil, avocado oil, wild-caught salmon, and grass-fed beef) and omega-3s (found in fatty fish)

Products Mentioned

  • Max Lugavere has noticed that if he consumes too much chicory root fiber, his stomach “blows up”
  • Psyllium husk, available most commonly in the form of Metamucil, can be used to lower cholesterol
  • Canned sardines are a great source of omega-3s
  • Glutamine has been shown to have a “barrier disintegrity reversal effect”
    • In simple terms – this means it tightens the junctions of your epithelial lining which makes it harder for harmful molecules to enter your circulation

Intro

The Microbiome 101

  • The microbiome is the community of organisms (viruses, bacteria, and fungi) that live in and on the human body
    • It consists of the gut microbiome, the skin microbiome, and the mouth microbiome (to name a few)
  • Your first exposure to bacteria is called “seeding”
    • It happens during passage through the vaginal canal at birth (if you’re born by c-section, you get it through skin-to-skin contact with your mother)
      • After two years of life, your microbiome is reasonably stable – “That’s, for the most part, the microbiome you’ll have for the rest of your life. It’ll change based on your diet and lifestyle, but that’s your baseline.”
      • “In the future, we’ll start collecting infant microbiomes around the age of 2 and keep them as a reservoir; you could always inoculate or repopulate yourself with that starting community later in life.” – Raja Dhir
  • Your microbiome determines/affects:
    • Digestion
    • Metabolism
    • Immune system function
    • Whether or not you have allergies 
    • Whether you have an increased risk of both neurodegenerative and cardiovascular disease
    • Whether you have an increased risk of infection
  • The microbiome is highly dynamic and is modified through diet and lifestyle
    • “No one really has a perfectly stable microbiome” – Raja Dhir
      • For one, taking a course of antibiotics completely messes it up
      • Antimicrobials found in foods like oregano can also change your microbiome over time
    • When you deprive your microbiome of building blocks for a short time (i.e., with intermittent fasting), the strong/beneficial bacteria tend to survive while the weaker/more harmful bacteria are killed off

A Diverse Microbiome Isn’t Always Superior

  • “There isn’t really one good microbiome. It depends on your genetics, where you grew up, what your upbringing was, and what your current lifestyle is like. You can’t say a more diverse microbiome is a better microbiome.”Raja Dhir
    • The Hozda people, a hunter-gather tribe in Tanzania, have the most diverse microbiomes ever to be discovered – “But there’s not any amount of money you could give me to take a Hozda microbiome because I’ve looked at the sequences and I know what’s in there”
      • They certainly have a high diversity of gut bacteria, but very few of those organisms would give Westerners any protective benefit

The Problem with Microbiome Diagnostic Tests

  • These microbiome tests are undoubtedly useful at giving you insight into the type of bacteria on/in your body, but as far as using the data to inform your diet… think twice
    • Concern 1 – “If you really want to get a sense of what’s going on in your gut, you shouldn’t take a toilet paper swab. Instead, you should use whole stool.”
      • Why? – The anaerobes (the bacteria that hate oxygen the most) concentrate in the middle of a stool sample
        • Thus – a toilet paper swab only samples rectal bacteria or bacteria on the outside of stool
    • Concern 2 – The diet recommendations “quite frankly don’t have any backing or basis in nutrition science”
      • For example – Say a microbiome diagnostic test determines you have a low amount of bacteria X (which is useful for converting compounds from cruciferous vegetables into a more bioactive form)
        • Perhaps this is the case because you don’t consume cruciferous vegetables in the first place
    • Raja Dhir adds – “It’s this overly reductive, isolationist approach to nutrition. I have a lot of criticisms about the actionable utility of these tests.”
  • Other swab areas are more reliable than stool samples (like the skin, vagina, and mouth)
  • To sum up – Exercise caution 
    • “This field is incredibly complex. What I’m interested in are the people saying, ‘This is the gut microbiome that prevents infants from getting allergies,’ or ‘This is the gut microbiome that makes your immunotherapy more effective if you have cancer.’ That’s the real science, and I think we pervert that science when we cheapen it with an at-home diagnostic kit that conflates itself as actionable; that data is really limited.” – Raja Dhir
  • A little laugh – Max recently completed a microbiome test; his results dictated that he had the microbiome of an obese person

Is the microbiome like a fingerprint?

  • Not really, but it depends on what vantage point you’re looking at it
    • Most healthy infants have similar microbiomes
    • If you’re looking at a microbiome from the level of Bacteroidetes (good bacteria) vs. Firmicutes (bad bacteria), then certainly people will have similar ones
      • But, if you dive deeper into the species/strain levels of bacteria, most everyone’s microbiome will be unique

Function > Identity

  • Different bacteria may perform the same function for different people
    • “Function is far more important than the identity of organisms when it comes to the gut microbiome”Raja Dhir
      • The way to examine function is by looking at gut metabolites (which is very expensive) 

How Artificial Sweeteners Affect the Gut Microbiome

  • The science:
    • Raja recalls a recent study showing that artificial sweeteners blunt the growth of beneficial bacteria
    • Another study found that when trying to break artificial sweeteners down, gut bacteria create toxic byproducts 
    • Another study in mice found that artificial sweeteners given orally caused their bodies to “prepare for a glucose response” (get ready for some form of energy utilization)
      • As that energy never came, these predictive response pathways became worn down over time, making the body less equipped to handle a true glucose challenge
  • Be cautious of sucralose and aspartame (commonly found in processed foods and diet sodas)
    • The science is still up in the air on stevia, monk fruit, and erythritol 
    • But it’s all relative – “Of course drinking an artificial sweetener-based beverage is better than consuming 100 grams of liquid sugar per day”

Foods That Benefit the Microbiome

  • The Human Microbiome Project recently found:
    • The number one predictor of a diverse and resilient microbiome is the consumption of over 30 different kinds of fruits and vegetables in any given week
      • “Diversity of diet is good for diversity of gut”Raja Dhir
    • A good predictor of an unhealthy microbiome is the consumption of <10 different kinds of fruits/vegetables in a given week
  • Society gets too wrapped up in the macronutrient debate (protein vs. carb vs. fat consumption)
    • “At a certain point, if 70-80% of your intake is vegetables and low-sugar fruits, you can eat whatever the f*** you want”Raja Dhir

Are certain foods harmful to the gut?

  • As mentioned, oregano contains antimicrobials which are harmful to the gut microbiome
  • In general, the food-microbiome interaction can get complicated:
    • When certain bacteria is killed off, room is created for more beneficial bacteria to be formed
    • Also, certain types of beneficial bacteria can cross-feed on the cell walls of dead gut bacteria 

Prebiotic Fiber

  • Max Lugavere has noticed if he consumes too much chicory root fiber, his stomach “blows up”
  • Consider whether the fiber supplement you’re consuming is fermentable or non-fermentative
    • If it’s the latter, go to town – it’ll aid in digestion and ease your bowel movements by increasing stool hydration
    • With fermentable fibers, be careful – they often lead to excess gas
  • If you eat whole food sources, you should have no problem meeting your basic fiber needs
  • Max Lugavere has recently drawn interest in using psyllium husk, available most commonly in the form of Metamucil, to lower cholesterol (it might be a good idea to try this method of lowering cholesterol before jumping on the statin bandwagon) 
    • It works by trapping your bile acids, thus forcing your liver to make more bile (and it does so by sucking cholesterol out of circulation)
      • So – make sure to take psyllium husk with a fatty meal that triggers the release of bile acids from your gallbladder

How Meat Affects the Microbiome

  • A while back, researches discovered a method by which red meat contributed to heart disease via the microbial production of Trimethylamine N-oxide (TMAO)
    • Carnitine in red meat (and choline found in egg yolks) is converted by the gut bacteria to TMA which eventually oxidizes to form TMAO
      • TMAO is believed to be atherosclerotic (it results in the hardening of blood vessels)
    • “I think there are several things that are bigger risk factors. Controlling for everything else, I’d say this is a lower risk compared to living a sedentary lifestyle, getting poor sleep, and being inactive.” – Raja Dhir
      • In summary – TMAO is only a minor concern, don’t worry about it if you’re living a healthy life
    • Also – there are ways to block the conversion of TMA to TMAO:
      • Eat/drink more compounds rich in DMB (found in red wine, extra virgin olive oil, and balsamic vinegar)
  • “If there are risks of meat consumption, they can be attenuated by appropriately adjusting your vegetable intake”Raja Dhir
    • For this reason, Raja Dhir doesn’t advise anyone to follow a carnivore diet
  • Are there any other risks of excessive meat consumption?
    • Some, especially if you have colon cancer that runs in your family
      • Specifically with undigested meat (so eat meat in small quantities – this allows it to be appropriately digested)
      • There’s also mechanistic evidence which suggests consistent exposure to red meat can increases the risk of mutations which result in colon cancer

All Fats Are Not Equal in the Eyes of the Microbiome

  • Saturated fat (if it makes up >25% of your total caloric intake) tends to increase the concentration of certain bacteria which don’t serve a known function. This simultaneously crowds out more beneficial bacteria that produce short-chain fatty acids (butyrates and acetates) (this is known as a dysbiotic shift).
    • A diet high in saturated fat prevents your gut bacteria from turning carbs into the type of fats that are good for you (AKA short-chain fatty acids)
    • These short-chain fatty acids affect:
      • Insulin signaling
      • Glucose tolerance
      • Risk of neurodegenerative disease
      • The gut lining (and in turn your immune response)
      • Weight (through regulation of metabolism)
  • “Monounsaturated fats are phenomenal for the gut microbiome. They’re not associated with any dysbiotic shifts, and they enrich certain organisms that produce short-chain fatty acids.” – Raja Dhir
    • This is the primary fat in extra virgin olive oil, avocado oil, wild-caught salmon, and grass-fed beef 
      • For background – grain-fed meat is higher in saturated fat
  • “Omega-3s are also phenomenal”
    • They increase the diversity of the gut microbiome, downregulate the inflammatory response, and have a restorative effect on tight junction proteins
    • For this reason, Raja Dhir will very frequently eat canned sardines (same with Max Lugavere) which are very high in omega 3s

Staving Off Neurodegenerative Disease

  • Glutamine has been shown to have a “barrier disintegrity reversal effect”
    • In simple terms – this means it tightens the junctions of your epithelial lining which makes it harder for harmful molecules to enter your circulation
  • One of these barriers is the blood-brain barrier (BBB)
    • Raja Dhir recalls reading about an interesting theory related to Alzheimer’s disease: It seems that, due to poor diet and lifestyle, the BBB starts to become permeable. This makes it more likely that harmful compounds get access to the brain.
      • Amyloid plaques develop as a protective mechanism, but in doing so produce a lot of collateral damage
  • In summary – When these barriers start to break down, things that shouldn’t be entering into systemic circulation do
    • In addition – normal immune processes that serve us when we’re healthy begin to cause harm

What does living a genius life mean to Raja Dhir?

  • Living life according to the principles of true science: hypothesize, observe, analyze, and reflect without having an attachment to outcome
    • “When you live by those principles, it’s a good north star to be steered by.” – Raja Dhir

Additional Notes

  • In 2006, Raja Dhir read a paper describing how transplanting a lean mouse’s microbiome into an obese mouse caused the obese mouse to become lean
  • Microbiome diversity determines how you’ll respond to cancer therapy
  • Max Lugavere has a cat named Delilah
    • He’s tried to feed her canned sardines, but she’s more of a fan of canned tuna
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