September 19, 2013

Digestion for (not-so) Dummies

Acid blockers, anti-gas meds, probiotics. Pills to make you “go” more often, and pills to make you go less often. If TV commercials, print, and online advertisements are any indication, we, as a population, are experiencing a massive epidemic of digestive distress. And for once, the ads are right! Good digestion is absolutely fundamental to good health. You cannot expect to have one without the other, and it’s usually the former that begets the latter. You can consume the highest quality foods that are all organic, biodynamic, grassfed, pastured meats and poultry, wild-caught seafood, and allow nary a single molecule of questionable food into the temple that is your body, but if you aren’t properly digesting, absorbing, and assimilating those pristine, blessed-by-the-gods foods, you won’t reap the benefits and you might as well hit up the nearest fast food joint. (Well, no, it's not that extreme, but you certainly won't be getting all the bang you could for the extra few bucks you're spending on the good stuff.)  

So, since I am, for once, in agreement with the mass media machine that’s telling us we’ve got serious issues with our digestion, I offer this series as a primer on our digestive systems. Over its course, we’ll cover the anatomy and physiology of our gastrointestinal (GI) tracts (what the parts are and how they work), how things are supposed to go from point A to B to C, what happens when they don’t go the way they’re supposed to, and how to fix it.

‘Cuz let’s face it: popping pills is a nice, short-term solution to the acute discomfort caused by things like acid reflux and constipation, but it does nothing to address the underlying causes. And most of these causes can be fixed with—you knew this was coming—simple diet and lifestyle modifications that require no prescriptions, no doctor visits, and no shelling out money to the corner drugstore. They do require slowing down a bit, calming down, and paying more attention to what we put in our pieholes. But wouldn’t you rather do those things than kill time in some sterile waiting room reading three-year-old People magazines only to see a doctor who has a whopping five minutes to spend with you and then sends you off with a pill to alleviate your immediate symptoms without trying to help you find an actual solution to the problem? (/endrant.)

Okay, that’s enough railing against the modern medical establishment. I’m not here to bash doctors; they’re mostly just victims of the insurance industry meat grinder and I imagine most of them wish they had more time for patient care and lifestyle coaching. So rather than focus on problems and shortcomings, let’s get started on solutions.

What is your GI tract and how does it work?

The GI tract is a long, hollow tube that starts with your mouth at the top and ends with…well, your bottom, at the bottom. (Can I use the word anus? Can we all be adults here and use anatomically correct words without giggling? Okay, fine, go ahead, giggle. In fact, I’ll help you: a coworker recently told me a story about a woman who was talking about cookies she had made, and she had used star anise. Except instead of pronouncing it one of the usual ways, ă-niss or a-neese, she said it like anus. Ha! Remind me to steer clear of the cookies with star anus in them!)

Woah, momma, that is one looong tube!

Okay, back on point. So yes, the GI tract is a long, hollow tube and, except for our skin, nasal passages, ears, and genital orifices (orifii?), it is our main point of contact with the outside world. In fact, until food is actually absorbed by the body, when it’s still moving around inside the GI tract, it’s considered to be outside the body. Aside from the exceptions noted above, the vast majority of nutrients, pathogens, and toxins that enter the body come in via the GI tract (i.e. with the food we eat and the beverages we drink).

The thing is, the actual digestive process starts before we even get to the GI tract. It starts in the brain. Digestion is a north-to-south process, and when it comes to the human body, you can't get much more north than the brain. (I guess you could say there’s the scalp, but that doesn’t do much for us besides grow hair and get sunburned.) As the authors of Why Stomach Acid is Good For You explain, digestion is like a row of dominoes: if the first one doesn’t fall as it should, the others won’t, either. Things have to work properly at each successive point because what happens early on triggers crucial events that happen later. And if those triggers are not…well…triggered, puppies & kittens get kicked. No, just kidding about that! No harm to puppies & kittens…just bad digestive juju that, over time, if not corrected, can lead to seriously bad health juju. (BTW: if you think the title of that book is a joke, I assure you, it isn’t. Stomach acid is very good for you, and we should not—repeat not—be trying to reduce it willy nilly with prescription or OTC antacids. More on this when we get to the stomach. I'll also post a detailed review of the book at the end of this series. It’ll make much more sense at that time, after we’ve learned how this all works.)

In upcoming posts in this series, we’ll go from north to south, addressing what happens at each step along the way and which organs are involved. We’ll cover such exciting things as:

  • The brain: The most important digestive organ not actually part of the GI tract.
  • The mouth: Your mom was right when she told you to chew your food!
  • The esophagus and stomach: As the World Churns.
  • The small intestine, pancreas, & gallbladder: Sweet! You’ll finally understand what your gallbladder is for! (And why it’s a damn shame so many people have it needlessly removed. As for the appendix, you’re on your own with that one, kids!) Also: the pancreas: it's not just for blood sugar regulation anymore! 
  • The large intestine: Decoding the secret messages your poop is sending you. (Oh, wait, I mean feces. Or stool. I said we were gonna be adults about this. Never mind…it’s poop. Poop, poop, poop! [Tee-hee!]) 

If you experience heartburn, GERD, bloating, gas, sour stomach, diarrhea, constiptation, or any other unfortunate result of compromised digestion, stay tuned. (Not to mention: osteoporosis, depression, infertility, anemia, memory loss/fuzzy-headedness, or any other major health situation that can be logically tied back to a derailed digestive train.)

In the spirit of not making a novel-length blog post for once, I’ll end this one soon. I do want to leave you with some things to consider in the meantime, though:

Digestion is an energy-intensive process.

The energy it takes to digest food is energy not available to the rest of the body after a meal. The old wives’ tale about not going swimming within (roughly) 30 minutes of eating is mostly true. Not because you’ll immediately drown, but because most of your energy will be focused on your GI tract, and if an emergency should arise in the water, you might not be able to respond quickly or strongly enough.

We can prove digestion is energy intensive by thinking about Thanksgiving dinner. After you eat, you’re comatose for an hour or two, right? You lie on the couch or plop down onto a recliner. You open the button on your pants, or maybe loosen your belt a few notches. You’re wiped out—and why? All you did was eat! The sheer volume of food you consumed means your digestive tract now has a lot of work to do—a lotta lot. So the rest of your body—like your brain and muscles—don’t have as much energy available to them. That’s why you feel sleepy and lethargic. This post-feast haze has nothing to do with eating turkey, so can we please, please bury the ridiculous notion that feeling sleepy after Thanksgiving dinner has anything to do with the tryptophan in turkey? (After all, you don’t feel that way after a turkey sandwich for lunch, do you?) The post-feast poopout is the result of two things:  1) The volume of food your body has to deal with means a large amount of blood being shunted toward your GI tract and away from other places.  2) The blood sugar dip. During that awesomely well-stocked Turkey Day dinner, you likely presented your digestive system with a huge, honking dose of carbohydrate, thanks to the warm rolls, cranberry sauce, candied sweet potatoes, mashed potatoes, and cornbread stuffing (or “dressing” if that’s what they call it where you live). And don’t forget about the pumpkin pie, cake, cookies, and whatever other desserts were there. So after insulin did such a good job of getting all that glucose out of your bloodstream and into your cells, now your blood sugar’s getting a little low. Hence, the lethargy. 

It’s not the tryptophan!

…But it could be the carbs!

(OT: Here’s the crazy thing about this phenomenon:  About 2 hours after you’re so full you think you’ll have to roll yourself home from your holiday host’s house, you kinda feel hungry again! What gives?! You probably just ingested enough food to keep you going for three days! It’s the blood sugar bit. Now you’re feeling a little noshy, so you go back to the dining room, where everything is still laid out because everyone was too busy digesting and no one had the energy to put anything away yet. [Hehheh.]  And what do you take? You’re not eyeballing the worked-over turkey carcass, which still has several pounds of meat on it. And you have no interest in another helping of green vegetables or buttery mashed potatoes. What catches your eye are the sweets. You cut yourself an extra sliver of pie, and swipe one more cookie off the tray. After all, no matter how much protein or fat you’ve taken in, there always seems to be space set aside for dessert, no?)

But I digress. We’re talking about the digestive train here, not the blood sugar rollercoaster. (There’ll be plenty of time for that later. Also: what's up with all the transportation metaphors? Is there an excretion sports car? Or an exercise rocket ship?)

Until we meet again, BE SURE TO CHEW!! (You'll find out why in the post about the mouth.)

Let’s keep this thing chugging along smoothly, shall we?
(Chew, chew...choo choo!)

P.S. Avoid the butt cookies!

P.P.S. Isn’t it interesting how both diarrhea and constipation are both signs of compromised digestion? Kind of like that hilarious Simpsons quote, when Chief Wiggum told his son Ralph, “If your nose starts bleeding, it means you’re picking it too much…or not enough.”

P.P.P.S. So much for me acting like an adult… 

Remember: Amy Berger, M.S., is not a physician and Tuit Nutrition, LLC, is not a medical practice. The information contained on this site is not intended to diagnose, treat, cure, or prevent any medical condition.


  1. I came across oss your blog after googling low stomach acid. I have enjoyed reading the older posts, especially the ones on the digestive system. I appreciate your humor and explanations that laymen can understand. Thank you for such informative and insightful articles

    Grace and peace,

    1. Thanks, Pat! Glad you've found something helpful here. :)

  2. I so enjoyed sharing your article with my Twitter followers. Your information is helpful, informative and a great resource for nutritionists like myself who need some relevant info to share with their followers. I am also always happy to support a fellow graduate!