Self-Care Challenge (Day 296): Learning About the Human Gut Microbiome

Cyntia Lair teaching a class at Bastyr on the microbiome

On day 296 of my 366-day self-care challenge, I learned about the human gut microbiome.

As a dietitian, I’m well aware that I have weird interests. I mean, who spends a Saturday learning about gut bacteria? (Or how landfills are constructed, for that matter?)

For the past sixteen years, patients and clients (and even strangers) have shared some, well…personal things about their digestive health.

It comes with the territory.

One of my college professors likened our digestive tracts to a giant donut hole, and when you really think about it, it’s pretty accurate. Food enters our giant donut hole, a lot of stuff happens to it in order for us to extract nutrients, and then what we don’t need comes out the other end.

Except the stuff that happens between the two ends of the donut hole are really, really, really complex.

And I happen to find that very fascinating.

So, as my self-care practice for the day, I attended a workshop on the Human Gut Microbiome at Bastyr University in Kenmore, WA.

What exactly is the human gut microbiome?

The human gut contains trillions of microbial cells, commonly referred to as microbiata, and each of these microbial cells contains unique genes that have an impact on the human body. The microbiata produce metabolic signals, many of which we don’t yet fully understand.

For a little perspective, there are more bacteria in the human body than there have ever been people living on this earth, and the average person has 2 to 4 pounds of gut bacteria living in their colon at any given time.

But what’s even more fascinating is that the human gut microbiome contains more genes than the human body itself – with the microbiome carrying 1,000,000 genes compared to the human genome’s mere 23,000 genes.

Further proof that humans are indeed an integral part of nature, not separate from it.

Can the microbiome be changed?

One of the most surprising things I learned is that researchers believe our microbiata profile is “set” by age 2 or 3, and while the numbers of bacteria may change over time, our profile remains unchanged. So, while we can introduce new strains over the course of our lifetime, it may not produce any real change.

This brought me back to my years as a nutrition consultant for long-term care facilities, where antibiotic use was quite common. A standard approach for preserving gut flora during treatment was to introduce cultured dairy or a prescribed probiotic.

I have to admit, it was an empirical treatment at best, and not one that I ever found to be consistently effective, but like many treatments in institutionalized care settings, doing something is always viewed as better than doing nothing, no matter how much it costs.

But like most researchers who study this relatively young science, I’m left with so many more questions than answers. Even the studies that have been conducted to date are limited at best.

As one of this workshop’s professors admitted, “What grows in the lab might not grow in the gut.”

More questions…

I’m left with so many questions:

  • Are there certain combinations of bacteria that don’t “play well” together, and is that perhaps why there’s so much geographical diversity?
  • How is our culture’s fascination with cleanses and supplements (and their excipients) impacting our microbiata?
  • Since it’s believed that our microbiata profile is established by age two to three, is attempting to introduce new bacteria even worthwhile?
  • Do manufactured, single strain probiotics change the microbiata profile in infants and toddlers, or is their profile dependent on environmental factors only?
  • How does the fact that 30% of probiotic supplements fall short of amounts listed on their label play out?
  • Since the short-chained fatty acids (SCFA) produced by microbiata alter the pH of the gut, how does that shift affect human health?
  • If there is indeed bidirectional communication between the brain and the gut, how does that affect human cognition?
  • How does soil exposure impact the development of the microbiata in children and adults?
  • How do fermented foods compare to manufactured supplements in terms of impact on the microbiata (and microbiome)?

And those are just a few of my questions.

I also find it intriguing that mothers experience a bacterial “bloom” just before giving birth, which has prompted many physicians who deliver babies by Cesarean section to proactively “swab” newborns with the bacteria they would have come in contact with had they been born vaginally.

The human body is indeed a mysterious machine. I don’t think we’ll be running out of questions any time soon. Learning is a self-care activity for me, and it’s a big part of my life.

If you’re curious about what’s growing inside your gut, you can send a fecal sample (along with $99) to the American Gut project. (Keep in mind, your results will only include bacteria found in your sample, and not what lives within the colon’s biofilm.)

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