It can be a confusing thing, that uncertain time after a diagnosis when you go gluten-free. What can you safely eat? And what is off limits?
The simple and obvious answer is a) that you don't eat gluten (wheat, barley and rye, and their relatives and derivatives), and b) that you may eat those grains and pseudo-cereals that are considered gluten-free (corn, rice, sorghum, millet, teff, quinoa, buckwheat, amaranth). (And then there's oats which, if they're GF are okay, but if they're cross-contaminated are not...)
But let me offer you this trick question: If you're gluten-free, can you eat - and do you eat - gluten? At first blush, your response is probably something along the lines of Of course not! Hang on, though. Consider this:
When you start poking your head around the world of gluten-ous and gluten-free grains, you'll eventually and inevitably come up against seeming oxymorons, combinations that conventional wisdom say are mutually exclusive. Such as references to "corn gluten." (Seriously. "Corn gluten" is a common term...in the UK, in animal feed and lawn weed treatments, and in the GF medical community. Don't believe me? Do a Google search...)
If you're just starting out on the gluten-free journey, and even if you've been on that journey for a while, seeing "corn" and "gluten" together can be more than a little unsettling. Wait, you think. Corn is supposed to be gluten-free. But corn gluten? Is that safe? Can I eat it? It can make your head spin.
Time for a lesson in cereal science. You've probably read - or been taught - that gluten is a protein found in wheat, barley and rye, and it's the cause of your troubles. That's a simplified part truth. Reality is a bit more complicated.
All grains pretty much contain four types of protein, in varying ratios and to greater or lesser degrees: glutelin, prolamin, albumin, and globulin. "Gluten," in the biggest picture sense, refers to the seed storage proteins...glutelin and prolamin. There's take home lesson #1: gluten = glutelin + prolamin. What this means, of course, is that since both gluten-ous and gluten-free grains contain glutelin and prolamin, in some sense, you do eat gluten even when you're gluten-free. (Unless you're completely grain-free, which absolves you of these nuances altogether...)
What has happened, though, is that the medical community, the media, the blogosphere, and the general public have unintentionally co-opted the term "gluten" to refer to the family of seed storage proteins (plural) in wheat, barley and rye that make people with Celiac Disease and gluten intolerance sick. Some who insist on an even stricter use of the term "gluten" suggest that it only refers to the proteins in wheat. Meanwhile, the gluten proteins of other grains such as corn and rice, since they don't make the Celiac and gluten intolerant population sick, are not considered gluten. The result is a situation where "gluten" refers to some gluten, but not all gluten. Just the "bad" gluten. Got that?
So we have gluten-ous gluten-containing grains, and we have gluten-free gluten-containing grains. Sheesh.
The difference comes down to who's in what family. It's a grain version of the Jets and the Sharks, or the Hatfields and the McCoys. On one side, you've got Triticae (wheat, barley, rye, spelt, etc.). On the other side, you have everyone else. And Triticae's gluten (bad) is different than everyone else's gluten (not bad).
As researchers have increasingly been finding out, it's the prolamin part of gluten that causes most of the problems for those of us that are Celiac or gluten intolerant. In wheat, the prolamin is gliadin; in barley, hordein; and in rye, secalin. (For those who are interested, the prolamins in other grains are: oats have avenin, corn has zein, rice has oryzin, and sorghum has kafirin, for a few examples.)
All of this may seem like silly semantic differences, and more info that you need to navigate daily life. To a degree, that's true. But on the other hand, when you come face to face with a reference to "corn gluten," you're hip to the game. You know that gluten is at once a broad umbrella term (referring to all cereal storage proteins) and also one that's been borrowed for a very specific use (to identify those foods, made from the specific cereals of wheat, barley and rye, that aren't safe for people with Celiac Disease and gluten intolerance to eat).
You now know that "bad gluten" is actually glutelin (glutenin in wheat, glutelin in barley and rye) plus prolamin (gliadin, hordein or secalin). And you know that "neutral gluten" is found in the gluten-free grains, yielding a quirky sort of grain quantum dynamics or theory of relativity; a gluten form of the wave-particle duality, or the Schrodinger's Cat thought experiment, in which two divergent possibilities simultaneously and paradoxically coexist - a gluten-free grain which contains gluten (but not bad gluten).
Remember: in the course of everyday living, if you're gluten-free, then gluten is bad and off-limits. All the usual rules apply. Wheat, barley and rye are bad. Other grains are okay. And yes, corn IS considered gluten-free.
But I hope that this more detailed, behind the scenes look at gluten (both big picture gluten and bad-for-you gluten) empowers you to be a more knowledgeable consumer and foodie who can be a better advocate for your diet and health.
P.S. Not to confuse the above post, but to also clarify... when you read about "glutinous rice," it - like corn - is gluten-free. There's a distinction between glutenous and glutinous. The difference between an "e" and an "i" is everything. In the context of rice, we're referring to a particular variety of sticky rice that gets sticky and gluey - hence glutinous - when cooked. But it sure isn't glutenous. That's another thing altogether.