Enzymes are important workhorses that spend their little lives sorting out parts. Different enzymes are perfectly shaped to deal with different sorts of starches and proteins and probably a bunch of other stuff as well. Some enzymes (like pepsin) prefer the highly acidic environment of the stomach to do their work. Other enzymes (like trypsin) prefer a slightly alkaline environment. So if the ph value of any part of your digestive track is off balance, nutrients won't be processed as well as they should be.
Once things are processed into their important and unimportant parts, the body then needs to send the sorted items to the right places. The digestive lining (again, not just in the tummy but all the way along the intestines) have the job of letting the important stuff through and keeping not only the unimportant but also the dangerous stuff out. Think of the stomach lining like a tough guy bouncer type. Better yet, think of it like a whole slew of bouncer guys all standing shoulder to shoulder for wall to wall digestive defenses. Nutrients are allowed through so they can enter the blood stream and feed the body. Everything else (the unusable bits as well as things like the e-coli bacteria that came riding in with your undercooked hamburger or the food coloring from that cool-aid you drank) are shuffled off to buffalo (which means they're flushed out of your system). You can apparently get a decent sense of how your insides are doing based on your poop. If you're going, at a minimum, once a day, and your potty visits tend to be quick and easy, then your insides might be pretty healthy. If that's not the case, then that's one indicator that something's wrong.
\So that's how it's all supposed to work. But there are lots of things that can go wrong along the way. (Remember, I'm still learning about all this so I might not be 100% accurate in my descriptions, but I think I'm getting the gist of what can go wrong.) For some folks who are predisposed genetically to celiac disease, there's a disconnect between the enzymes that they're carrying in their gut and the shape of the gluten proteins entering the gut. (There's an interesting series of posts from people who are gluten intolerant who claim to not be able to consume even a teeny bit of gluten in America, but when they visit Europe they're able to eat pasta and bread without any problems. One difference could be the amount of gluten in American wheat products vs. European. But another possibility is that Europeans grow a different version of wheat which contains a form of gluten that's easier to process than the gluten found in American grain. I didn't see any scientific answers on this one, but the number of folks claiming to have experienced the difference leads me to believe that it's not necessarily gluten that's the problem but a specific variant or mutation of gluten that's causing the problems.) Proteins can fold. I'm a bit foggy on all this, but it sounds like some gluten proteins are folding their little selves in such a way that celiac's enzymes simply can't process them. So instead of having nutrients separated from unusables, these tummies are left with those original proteins, unchanged. In other words, the initial processing system breaks down, leaving proteins in the system that aren't supposed to be there. These proteins can eventually cause lesions in the digestive lining. It's almost like the unbroken down proteins act as little irritants that eventually scrape away the health of the lining. Imagine putting broken glass in the washing machine when you're cleaning your clothes. You'd end up with shredded clothing. I think that's what's going on in the tummy of the person with celiac disease. And even if you don't get to the point where there are lesions, all that scrubby activity can still lead to inflammation and tummy pain.
Even those that aren't genetically prone towards celiac disease can still have problems with nutrient processing. If something happens and you lose a lot of your enzymes, or they become unhealthy (perhaps due to a yeast infection or a problem with your ph balance), then an otherwise healthy gut can become broken and have similar problems to a person with celiac disease.
And that's just the beginning of the problem. Things aren't going well inside the digestive tract, but now the walls of the digestive tract start to get worn down and sick and stuff that's not supposed to get through starts slipping through. All those bouncers standing shoulder to shoulder are getting doubled over with pain and while they're down, proteins and other stuff start slipping into the blood stream. They don't belong there, and the body knows it. It sends in the army, the auto-immune system, to start taking out the bad guys and protecting itself. This leads to more inflammation as well as all sorts of other reactions (like a runny nose, itching all over your body or localized to certain areas, arterial deposits, and possibly even bigger problems like type 1 diabetes, multiple sclerosis, and some other big time stuff.). Some of those proteins on the loose can even make it up to the brain where they cause problems such as autism symptoms, AHDH symptoms, mood swings, and depression.
And to make matters worse, not only is the stomach lining allowing stuff through that it shouldn't, but it's also not letting through all the stuff that it should. So you might recognize that something is wrong with your digestive tract and start taking vitamins, eating special foods, etc, but if that lining isn't fixed, it won't make one iota of difference. You have to heal the gut before it'll work properly enough to get the good stuff to where it's supposed to go to heal the rest of your body.
All of this is referred to as a leaky gut. Stuff is getting through your digestive lining that's not supposed to be allowed through. I think the term is gross and when I first heard it didn't sound at all to me like what it means. I think "broken gut" or "confused gut" or something like that might fit better with what's going on. But the term that's been coined is leaky gut, so that's what we have to roll with.
If you have a leaky gut, what do you do? The first step is to try to remove some of the foods that aren't being processed properly. This might mean changing your diet to remove gluten, casein, perhaps even eggs, nuts and other common allergens. This will help the gut to have a break from being bombarded with bad guys. Then you have to do things that will help it to heal. You can take colostrum (Yes, the same stuff that new mom's produce for their babies for several days after birth. That's the stuff that coats the baby's digestive tract and helps to protect it from just such problems as these.) either by pill or as a powder mixed in drinks. I've just recently read that glutamine can be helpful as well. And chicken soup, believe it or not, is supposed to work wonders. (When you make the soup, boil the chicken bones for a couple of hours because that's where the helpful stuff is and you need to boil it out into the broth.)
Probiotics (good bacteria) can also help. One way to get probiotics is through pills, but you can also eat yogurt (not the sugary stuff but something with acidopholus and the like). Fermented foods (sauerkraut or kim chi, for example) are full of healthful bacteria. Kefir and kombucha are fermented products and full of good guys. And green leafy veggies are important. Not only do they have nutrients that many people are lacking, but there's fiber in there that apparently count as prebiotics (I just heard about them for the first time today) because they feed other healthy organisms in the gut. I should quickly point out that one instigator of an unhealthy gut is often antibiotics. The antibiotics aren't targeted so they affect all the healthy bacteria in the tummy as well as the bad guys. If the good guys get wiped out often enough they may never get back to full strength without some serious, concerted help on your part.
And what we're learning at our house is that it also takes time. You can't change your diet one day and the next day expect to see immediate change. There are stories of that happening, but there are also stories of it taking a month or more to see good come from the dietary changes. In our household we're hoping that once digestive tracts are happy and healthy, we'll be able to add gluten and casein back into our diets. (According to the doc, casein is a possibility but gluten isn't. We'll see. I've heard from more than one person that once you're off gluten entirely, even just a little bit can end up making you really sick.) In the meantime I'm learning all kinds of stuff about how the gut works, and I'm discovering lots of great recipes that are helping me to get more fruits, veggies and nuts into our family's diet.
If you'd like to learn more, here's a really helpful video that our doctor recommended.
The first and third images used in this article from SCDLifestyle.com (I also recommend the article that the images came from. You can click on the link to get to it.) and the second photo is from JustonHealth.com.