Unless you’ve been living under a rock, you’ve probably heard the terms gluten intolerance or gluten sensitivity and celiac disease tossed around a few dozen times in the past few years. If you spend a lot of time on MindBodyGreen, you already know that consuming gluten can negatively impact your health. What you might be a little hazy on are the specifics; why exactly is gluten harmful and what’s happening inside your body when you eat that bagel?
First things first: What is gluten?
Gluten is a two-part “sticky” protein found in grains, most notably wheat, as well as rye, barley, and others. It’s considered sticky because it holds together the nutrient stores of the plant it’s in. This stickiness is why it’s so commonly used in processed foods as a binder and filler. It’s a two-part protein because it’s made up of the peptides gliadin and glutenin.
Why is gluten such a problem now?
We're no longer eating the wheat that our parents ate. In order to have the drought-resistant, bug-resistant, and faster-growing wheat that we have today, we've hybridized the grain. It's estimated that 5% of the proteins found in hybridized wheat are new proteins that were not found in either of the original wheat plants. These "new proteins" are part of the problem that has lead to increased system inflammation and intolerance of gluten.
Today’s wheat has also been deamidated, which allows it to be water soluble and capable of being mixed into virtually every kind of packaged food. This deamidation has been shown to produce a large immune response in many people. Lastly, in our modern fast-paced world with fast food at our fingertips, we're eating much more wheat than our ancestors ever did.
So, what happens when we eat gluten?
Whenever the whole-wheat pasta or a 12-grain sandwich you innocently eat for lunch reaches your intestines, something called tissue transglutaminase (tTG), which is an enzyme produced in your intestinal wall, breaks down the gluten into its building blocks, gliadin and glutenin.
As things make their way through your digestive system, your gut-associated lymphoid tissue, or GALT, which is the term for the immune system in your gut, reviews everything to check for potentially harmful substances. In people who have no issues with gluten, this process goes smoothly and the food is absorbed. In those with gluten sensitivity, the GALT identifies gliadin as a dangerous substance and produces antibodies to attack it. In celiacs these antibodies don’t just attack the gliadin, they attack the tTG as well, which is what originally broke down the gluten into its two parts.
This enzyme, tTG, has a number of jobs, but one of its most important contributions to the body is holding together the microvilli in our gut. Your body collects nutrients by absorbing them through the walls of your intestines, and the more surface area there is, the more they can absorb. Imagine trying to soak up a gallon of water with a paper towel versus a bath towel. Microvilli, which look like hairy fingers, exist in your intestines to increase the surface area and absorb nutrients.
When the antibodies your body produced to defend itself against gliadin attack your tTG, these microvilli can atrophy and erode, decreasing your ability to absorb nutrients and allowing the walls of your intestines to become leaky. This can manifest itself in digestive symptoms, including bloating, constipation, diarrhea, weight loss, fat malabsorption, and malnutrition like iron deficiency or anemia, low vitamin D or even osteoporosis. This blunting of the microvilli is the hallmark of celiac disease, which is an autoimmune disease.
How does gluten cause intestinal permeability, AKA leaky gut?
As mentioned above, in order to absorb nutrients, our gut is somewhat permeable to very small molecules. Regulating intestinal permeability is one of the basic functions of the cells that line the intestinal wall. In sensitive people, gluten can cause the gut cells to release zonulin, a protein that can break the tight junctions apart.
Once these tight junctions get broken apart, you're considered to have a leaky gut. When your gut is leaky, toxins, microbes and undigested food particles — among other things — escape from your intestines and travel throughout your body via your bloodstream. One of the things allowed to escape are the antibodies your body produced to attack the gliadin in the first place.
What is the link between gluten, systemic inflammation and autoimmune diseases?
Unfortunately, these antibodies often confuse more than just tTG for gliadin, and end up attacking other organs and systems, from the skin to the thyroid to the brain. This is why gluten sensitivity is so frequently paired with autoimmune conditions, and why those with celiac disease are at risk of developing a second autoimmune disease.
Gluten is causing your body to attack itself, sometimes on multiple fronts. The fact that something you eat is causing an issue for you outside of your digestive system, such as rheumatoid arthritis or autoimmune thyroid, is why many people go so long without realizing they have a problem with gluten. If you have an autoimmune disease you should get tested for gluten sensitivity, and if you're gluten intolerant you should get screened for autoimmunity.
What should you do if you suspect you're gluten intolerant?
I've found the single best way to determine if you have an issue with gluten is to take it out of your diet for at least three weeks, then reintroduce it. Please note that gluten is a very large protein and can take months to clear from your system, so the longer you can eliminate it from your diet before reintroducing it, the better.
The best advice that I share with my patients is that if they feel significantly better without gluten or feel worse when they reintroduce it, then gluten is likely a problem for them. In order to get accurate results from this testing method, you must eliminate 100% of the gluten from your diet.
Another way to determine if you're gluten sensitive is to ask your doctor to order the following tests: