How Your Body Works: A Day in the Life of Your Gut

One gabby gut shares how a bad day can affect your mood, your immunity, and, yes, your digestion.

day in the life of your gutSerge BlochFunny how a day can change so quickly. It started well: The Body had one of my favorite meals for breakfast—yogurt and oatmeal with blueberries. I’ll be running smoothly, if you know what I mean, thanks to the fiber in the oats and fruit. Even better, the yogurt is teeming with probiotics—live bacterial critters that help maintain my Gut Flora (GF), the amazing microbes inside me that help with digestion and immunity. When my GF are balanced and happy, The Body may be more likely to eat that who-knows-how-old Chinese food in the fridge without getting sick.

But more about that later. It’s only 8:30 a.m., and my optimism is fading on the morning commute. The Body remembers that late-night e-mail from her boss (“See me at 3:30 tomorrow.”) Hmm … doesn’t sound like a promotion. And the traffic is brutal! Time to say hello to stress chemicals like cortisol that can become my enemies when they are the constant background music of The Body’s demanding days. Hey, she gets a lot done, but I pay the price. When her stress hormones spike, her brain signals specialized cells in my lining to release inflammatory chemicals. These guys are useful if there’s actually an infection to fight. But when there’s no real threat, they cause muscle contractions that can make me bloated and irritated (hello, cramping and the need for the nearest bathroom). This can also kick The Body’s irritable bowel syndrome (IBS) into high gear. That means I have to deal with excruciating, stabbing pains. Fun, huh? Note to self: Strategize with the brain about ways to help The Body chill a bit. Yoga isn’t helpful if she checks her BlackBerry before every Downward Dog.

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day in the life of your gutSerge BlochMy Secret Balancing Act

I think I just felt the Gut Flora I mentioned earlier kick in. These guys—a teeming mass of around 100 trillion microorganisms that live on my lining—are pretty spectacular. Most of them are solid citizens, little worker bees that help with digestion by breaking down nutrients and keeping various germs in check. That’s why I beg The Body to eat more fiber and yogurt, like she did today for breakfast. These “prebiotics” (think oatmeal and blueberries) and the yogurt’s probiotics are like diligent hall monitors, allowing the good GF to do their jobs without distraction from the mischief-makers.

That’s right—some percentage of the GF are a little, well, misguided. And when these bad bacteria run rampant, The Body knows it. I get out of whack and make her feel gassy, bloated, and gross. (So long, skinny jeans.) Some experts say that when I have too many of certain microbes, I might make The Body gain weight, trigger autoimmune diseases, and bring on depression. (Geez, way to make me feel bad.)

The Body starts plugging away as soon as she gets to her office. I’m starting to feel a little parched—is she really too busy to stop for a water or snack break? When lunchtime rolls around, I’m anxious (that 3:30 meeting is getting closer) and famished—a bad combo. I know she’s going to wolf down that Grande Taco Sampler way too fast.

Once the chewed-up, mushed-up lunch arrives in my stomach, I go to work. I start giving it a good massage, flexing my muscles in gentle, rhythmic contractions to break it down. Then my chemicals kick in—hydrochloric acid dissolves the tortilla, beans, and guacamole with the help of those massaging muscles. It’s potent stuff. Think of me as a washing machine, but instead of wringing out stains, I wring critical nutrients from The Body’s food.

I’m one sophisticated piece of machinery, if I do say so myself. By the way, my stomach is probably smaller than you think. Picture a hollow sac, about the size of an empty fist, located just below the ribs on the right. But I’m super-stretchy. On Thanksgiving, for example, I’ve been known to hold a quart, maybe a quart and a half, of turkey, stuffing, and Aunt Jody’s candied yams. And I’m savvy enough to process each food group—proteins, fats, and carbohydrates—at different speeds and with the help of different digestive enzymes. Fat takes longest, FYI. So this hearty taco lunch, which is loaded with fat, along with protein and fiber, will take me several hours to process.

day in the life of your gutSerge BlochMy Gut Instinct

At her desk after lunch, The Body tries to focus on the 53 unread e-mails in her inbox, but I can’t help but distract her with my uneasiness. It makes her realize she’s worried about her ninth grader, Luke. She calls it a gut feeling, and she’s right. Some scientists call me the second brain because I have 100 million nerve cells, called the enteric nervous system (ENS), embedded in my lining. The other brain and I work closely together all day long, passing information through our nerve cells and hormones, essentially playing puppet master over The Body’s mood. When I’m feeling off, I send messages to the other brain that make The Body feel anxious. I make her pay attention to those cues she’s been getting from Luke that all is not well. The brain gets all the credit, but I’m pretty darn smart too. (And by the way, I’m right about Luke: He’s flunking math and doesn’t want to tell The Body.)

Uh-oh. It’s time for that mysterious meeting. Cortisol spikes! Heart rate skyrockets! Blood pressure jumps! I wish I could say I stay calm, but I’m in knots. Then my worst nightmare happens: Office silence is disrupted by a loud, yerping, blerping noise. Yes, it came from me. Hey, you try massaging a jumbo taco platter into mere molecules without a peep! Can’t be done. Thankfully, The Body’s job isn’t in jeopardy; in fact, her boss just wants to thank her for putting in some extra hours last week. She sighs with relief.

As her stress level drops, I go back to digesting that taco properly. Her lunch continues to move out of my stomach and into my small intestine. Actually, there’s nothing small about it. Picture a tube, maybe an inch in diameter, which meanders back and forth through the lower torso for more than 20 feet. Every bit of this vast surface is a transit point for the nutrients I’ve just harvested from lunch. They ooze through my intestine walls into the circulatory system, coursing through 60,000 miles of blood vessels to deliver essential raw materials to every inch of The Body.

She decides to hit the gym after work, but I wish she’d wait a little longer. She just polished off a big slice of office birthday cake, and Zumba class moves the blood away from me and toward her heart and muscles. Fair enough, they’re doing all the work. But still, the intense exercise slows me down. When The Body waits at least an hour after eating, I’m actually a big fan of regular exercise because it makes me more efficient. Aerobic exercise is my favorite. Over time, The Body’s workouts keep my muscles in good shape so they contract more easily and push food through so I don’t get backed up.

When The Body finally gets home, I want dinner immediately. Greek salad with shrimp—yum. It’s a big improvement over the taco disaster, and I’m excited to get down to business. But … wham! She lies down right after her last bite. It’s tough to blame her; she’s exhausted. She does so much for everyone. But as she hits the couch, all the hydrochloric acid I’ve deployed to digest her dinner sloshes up toward my esophagus where it definitely does not belong. Ouch! That burns!

A couple of hours later, The Body decides to call it a night. But I never sleep. I’m a round-the-clock organ, turning those olives, feta, and shrimp into the energy she’ll need to face tomorrow. I’ll try to harness my enteric nervous system to send her sweet dreams.

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Originally Published in Reader's Digest