Gut Pilot January 18, 2024

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"The past is an old armchair in the attic, the present an ominous ticking sound, and the future is anybody's guess." James Thurber​​

I'm purposely skipping any unfinished business from last week, so I don't get sidetracked- which is very easy to do.

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It's really easy to go down the science "rabbit hole" when the subject of circadian rhythms is discussed but we're not going to do that this week. I did enough of that last week with Akkermansia. (Thanks for keeping me honest Cobber)

"Most essential functions and processes that go on in our bodies run on internal clocks, including our hormones, immune system, and digestion." That's how Alicia Roth, Ph.D. from the Cleveland Clinic's Sleep Disorder Center describes it. These processes work in harmony with each other on a 24-hour master clock of sorts.

When I used to hear "biological clock", I would invariably think of the child-bearing years for a woman. Now when I hear biological clock, it's the circadian rhythm clock. I think of it as the 60 Minutes stopwatch ticking in my body.

It's no secret, gut health has a huge impact on digestion, intestinal metabolism, the immune system, and that hormones play a big part in both the immune system and the gut-brain connection. These systems also work on a 24-hour cycle. When they are in sync, they are very efficient at completing their assigned tasks. When they are not, things can go bad in a hurry.

Circadian rhythms use signals or cues, both environmental and external to influence them. In the world of neurobiology, these signals are referred to as "Zeitgebers", a German word meaning time-giver or synchronizer.

I only want to focus on two of these external cues, sleeping and eating. The sleep-wake cycle is probably the most recognizable Zeitgeber that influences our circadian clock, but eating is a close second, especially how instrumental it can be to gut health.

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Light is probably the best influencer on the body's master clock. Morning light signals the brain to start cortisol production and stop melatonin production, letting your body know that your day has started. The more of these cues to the time of day and night you can give your body, the better off you'll be. It's why sunlight is recommended first thing in the morning.

So, if sunlight is the cue that lets your body know when to wake up with cortisol production, darkness is key to melatonin production and sleep. Establishing good pre-sleep habits like winding down a couple hours before bed, turning off electronic devices spewing melatonin-aggravating blue light, or maybe taking a warm shower helps in this process.

When we sleep well, the orchestra of bodily functions sounds divine. When we don't, it sounds more like a children's musical with every instrument wincingly out of step.

We've all been members of these bands or suffered through kids' productions years later. Cute but painful.

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Not nearly as impactful as sleep, eating is another subtle cue that keeps the body in rhythm. "With the first bite of food, we signal our digestive system (clocks in the liver, heart, muscles, and kidneys) that it’s time to get to work", says Azure Grant, Ph.D., scientist-in-residence at Crescent Health.

He continues “When you eat late at night, your organs have no choice but to ramp up to process the food rather than wind down for rest, which isn’t good for them or conducive to good sleep.”

With both of these Zeitgebers on the radar screen now, let's tie them into gut health.

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When it comes to feeding time, the circadian system controls rhythms in gastrointestinal digestion, absorption, motility, hormones, barrier function, and the gut microbiota. This pretty much sums it up.

When it comes to sleep, the same circadian system controls rhythms in the gut microbiome. Bacterial activity and levels are different during the sleep and wake cycles. When these rhythms are interrupted, the gut suffers.

It's a two-way street of sorts. If we eat poorly and upset the balance of good and bad bacteria, it will affect our sleep. When we sleep poorly, it is both a cause and effect. It causes gut dysbiosis and is an effect of the same imbalance. Gut dysbiosis leads to a leaky gut, chronic inflammation, and overall poor health outcomes.

This is quite the vicious cycle.

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I wrote the manual on how to destroy a gut, that's been established. Abysmal sleep habits and a poor diet, for decades, were two of my hallmarks. But I actually learned, lived, and functioned quite a bit in a circadian rhythm- dependent environment. At the time, I thought I was winning the battles, but I clearly lost the war.

Being in aviation in the Army for almost a decade, we trained and operated in the dark. When you're flying a helicopter that measures nearly 90 feet from tip to tip, it's large, loud, and creates quite a bit of wind and dust. Flying in the dark is the only way to avoid the bad guys.

So, I spent quite a bit of time wrestling with circadian rhythms, going on endless "reverse-cycles" inverting the normal sleep-wake cycles. Believe it or not, your body can adapt to consistent sleep-wake cycles that are reversed. Shift workers successfully do this quite a bit WHEN they are consistently on the same shift. The trouble comes when there is no consistency.

I also lived in Fairbanks, Alaska for two years. In a 12-month calendar, there were about 2 months of what I would call normal daylight-to-darkness balance. The rest of the time it was overwhelming daylight or crushing darkness.

It was the reason new people to Alaska would accidentally crank up their lawnmowers at 11PM before getting yelled at by their neighbors. It was also why you had to power through the yawns at 4 PM to convince your body it was not quite time to go to bed.

I managed this voyage largely because I was young, very fit, and the twenty-something body can withstand quite a bit of abuse. But what I believe led to my demise were the poor eating and sleeping habits I developed during these trying times.

I wish I knew then what I know now. I know my gut does.

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Next Week- The Colonic Brake. And no, it's not an auto part!

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Thanks for reading!

Jeff