Welcome to The Long Haul! Every week, I’ll explore a longevity topic and then give a roundup of the big news in Longevity.

Adding on from last week, let's talk gut health & probiotics.

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The TL;DR

🧠 Your gut is a key part of your nervous system influencing several key bodily functions

🧬A diverse, flexible, and stable microbiome is correlated with living longer

💊 Probiotics & green drinks aren’t the answer, one study shows probiotics reduce microbiome diversity

🛟 Eating fiber & probiotic rich foods, exercising, and having a dog all increase microbiome diversity

Today's Topic

Gut Health

In 2019, I went to Egypt and came back with a parasite. Thus began my fascination with gut health. 

Gut health has been a huge topic for the past couple of years. And for good reason — it’s estimated that 70% of our immune system is located in the gut. [1]

Our gut has significant control over how we feel mentally and physically, and good gut health is correlated with longevity.

What is the gut?

The gut, aka the gastrointestinal tract, goes from the esophagus to the rectum. It’s lined with 2 layers of more than 100 million nerve cells. [2]

There are so many nerve cells in the gut that it has a nervous system name — the enteric nervous system. [2] 

The gut and the brain influence each other in lots of ways:

The gut is full of bacteria (or microbiota) that make up the microbiome. Every person on earth has a unique microbiome that influences what signals are sent to the brain. 

A “healthy gut” means a healthy microbiome, and it’s carefully balanced by several factors:

• Diet

• Exercise

• Stress

• Medication
  
  

That, of course, means it’s crucial for our overall health. 

The gut & longevity

One systematic review (a study of many studies) found that diverse, flexible, stable microbiomes are correlated with living longer. [3]

Let's break that down: 

• Diversity: more varied types of bacteria in the gut

• Flexibility: how adaptable the gut is to changing stimuli (diet, environment)

• Stability: the gut resisting the natural process of reducing diversity as we age

Good gut health in seniors is associated with:

• Lower cholesterol levels, reducing heart disease risk

• Faster walking speeds, indicating good strength and balance

• Higher levels of beneficial blood chemicals [4]

So how do you get good gut health?

The answer isn’t probiotic supplements & green drinks (...goodbye Athletic Greens sponsorship).

Remember when we broke down why supplements don’t work?  

Probiotics are in the same camp. I doubt their effectiveness. Studies have shown green drinks like Athletic Greens & Bloom generally don’t work.

The “proprietary blend” they tote hides nutritional facts and is filled with uselessly tiny amounts of enzymes, vitamins, and minerals. Our highly acidic stomachs usually break down the probiotics in the drinks before they get absorbed. [5] 

Some doctors recommend probiotics to repopulate your gut after antibiotics, since antibiotics wipe out all the bacteria, good and bad, in your body. 

But one admittedly small study (only 21 people) showed that participants who took probiotics actually saw slower microbiome recovery than those who took nothing. [6] 

The group that took probiotics was shown to have a less diverse microbiome and no return to normal even 5 months after antibiotics. 

Once again, this is a very small study, so we should take it with a grain of salt. But the results are alarming — probiotic supplements may be doing more harm than good. 

Improving gut health

Eating the right food is the biggest factor in improving your gut health. But here’s a full list of things you can do:

1. Eat healthy foods
   
   

   Our gut improves when it’s full of healthy bacteria. Bacteria flourish when provided with food (sugar) they can use to grow. Because we’re greedy, we take most of that sugar out of food earlier in our digestive system. Fortunately, we can’t digest most fiber. This means fiber can be pushed through our digestive system for bacteria to feast on in our gut.  
   
   Fiber is found in fruits & vegetables, and whole grains. You can also supplement your diet with fiber.
   
   

2. Eat probiotic foods
   
   

   Foods like yogurt, sauerkraut, kefir, and kimchi are rich in probiotics and have enzymes and cofactors (unlike most supplements) that ensure the healthy bacteria is carried to the gut.
   
   
   

3. Exercise
   
   Shown to promote gut diversity. [6]
   
   
   

4. Dogs
   
   

   Studies show young children who grow up with dogs have more diverse microbiomes. We don’t know if it helps when you’re older… but why not have a friend? [7]

Good gut health is crucial for our longevity, and it’s relatively easy to make small adjustments for major improvements. But just like supplements, it’s important to think critically about small bottles with huge value propositions.

The Haul: What you can’t miss in longevity this week

Research

• Caloric restriction impacts longevity: Caloric restriction increases telomere loss until weight is stabilized

  
  

News

• HIV contracted through Vampire Facial Needles: The first documented cases of HIV transmission through cosmetic needles occurred because of vampire facials in an unlicenced medical spa — take needles seriously!
  
  

Podcasts

• Peter Attia’s Drive Podcast tells us how to optimize muscle protein synthesis

  • Age-related muscle loss isn’t inevitable, it’s triggered by inactivity and poor diet

  • Our bodies can process more than the previously thought 40-50 grams of protein in a meal. High doses of protein can increase muscle protein synthesis for longer than originally thought.

  • Prioritizing protein intake immediately after workouts enhances muscle protein synthesis

  • Collagen supplementation doesn’t really boost muscle protein synthesis

  
  
  

How do we feel about the TL;DR at the top? Reply and let me know.

Thanks for reading.

– Robyn

Interested in advertising? Reach out to robyn@girdley.com.

[1] https://www.uclahealth.org/news/resetting-gut-microbiome-is-a-long-term-project 

[2] https://www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection 

[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7762384/ 

[4] https://www.nia.nih.gov/news/unique-gut-microbiome-patterns-linked-healthy-aging-increased-longevity 

[5] https://pubmed.ncbi.nlm.nih.gov/25103998/ 

[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5357536

[7] https://www.health.harvard.edu/staying-healthy/healthy-gut-healthier-aging 

DISCLAIMER: None of this is medical advice. This content is strictly educational.