Thursday, April 10, 2014

The Promise and Perils of Celiac-Safe Wheat

Last month I looked at whether today's gluten is more toxic to those with active celiac disease than the gluten of old. The general answer is "yes," though it comes with a healthy dose of caveats and nuance. In this post, on the other hand, I'm flipping the toxicity question on its head and examining what recent research has found regarding the prospect of celiac-safe wheat and gluten. You read that right: the prospect of celiac-safe wheat and gluten. It sounds like an oxymoron, and for all practical purposes it is, but the research is intriguing, even if celiac-safe wheat remains an idea much more than a near- or even mid-term possibility.

Mind you, I'm not talking about gluten-free foods for those with celiac disease made from wheat starch that's been isolated from the problematic gluten through processing. I'm talking about plain wheat—gluten and all—but without the toxicity that makes it off limits to those of us with celiac disease and other gluten issues.

Remember: As the thinking goes, for a person to develop active celiac disease (and thus for wheat to become a dietary and major health problem), you need three things: 1) a genetic predisposition, 2) a trigger that turns the disease on, and 3) dietary exposure to celiac-toxic gluten. That last part is crucial: celiac-toxic gluten.

Not all gluten is evil, and no, I'm not crazy for saying that. Saying "gluten" is like saying "human" or "insect." You've given some information, but you've also glossed over tremendous amounts of variation within the umbrella category. When we talk about gluten in relation to celiac disease, what we really care about is not gluten generally but rather the specific sequences of amino acids—especially common in, though not exclusive to, the alpha gliadin forms of gluten coded for by the 6D chromosome—that are toxic to those with celiac disease. That's really where the celiac rubber meets the road.

In theory, you could identify naturally occurring (or develop scientifically) varieties of wheat whose gluten retains its desirable baking characteristics while leaving behind its toxicity. Sounds like a pipe dream, doesn't it? Except it might not be.

Wheat Gluten Without the Toxicity

Numerous studies from within the past decade have identified naturally occurring varieties of wheat and its relatives that have low or even potentially no celiac toxicity. Consider this representative sampling:

  • A 2009 study found a wide variety of alpha gliadin gene expression in tetraploid and hexaploid wheat varieties, including great variation in celiac-specific epitopes that would cause a reaction. Researchers pointed to the possibility of screening to pre-select wheat varieties with very low celiac toxicity potential.
  • A 2010 study similarly examined 11 wheat cultivars, including 3,000 gene sequences that all coded for alpha gliadins. They found naturally occurring sequences that coded for gliadin peptide sequences that lacked celiac toxicity.
  • Another 2010 study examined more than 80 modern and ancestral wheat varieties. They found modern and ancestral varieties alike that contained relatively low levels of toxic gliadin, leading researchers to suggest that "low celiac toxicity" could be a new wheat breeding trait.
  • A 2011 study also concluded that naturally occurring variation could yield gliadins that lack toxicity.
  • An earlier 2005 study looked at diploid, tetraploid, and hexaploid wheats. Researchers found a variety of toxicity levels, promising enough "to endeavor the selection of wheat accessions that contain low amounts" of toxicity, and that this process could lead to the selection and breeding of wheat varieties "suitable for consumption by [celiac disease] patients."
  • Another 2005 study likewise found wheat varieties, especially in the diploid and tetraploid families, where toxicity was nearly absent, raising "the prospect of identifying or producing by breeding wheat species with low or absent levels of harmful gluten proteins."
  • A 2006 study also found essentially absent levels of toxicity among some ancestral varieties.

Meanwhile, in 2010 another set of researchers took another approach. Instead of identifying naturally occurring wheat varieties with low levels of celiac toxicity, they used a technique known as RNA interference to effectively "turn off" the genes that code for toxic gluten. They were largely successful. Researchers concluded that this method "can be used to obtain wheat lines with very low levels of toxicity for [celiac disease] patients."

Two Major Red Flags

This may sound exciting and promising to some folks who long to cook and bake with wheat again and taste its flavors, but there's a long and perilous road to first navigate between the labs of researchers and the agricultural wheat fields of our food supply. I can think of at least two major red flags that would require major address:

Guaranteeing lack of toxicity

It takes a pretty substantial dose of scientific rigor and confidence—even hubris, potentially—to proclaim a wheat variety completely free of celiac toxicity. While we know that the alpha gliadins of the D genome are the worst gluten offenders, we also know they are not the only ones. How are we to know that science has fully, completely, and comprehensively identified all amino acid sequences of gluten that are toxic to those with celiac disease?

The short answer is that we can't be so sure. In fact, researchers from a 2006 study raised just this very concern. They wrote, "There may be more, still unknown ... epitopes of gluten." They later continued, "It may be premature to start breeding of non-toxic wheat varieties."

Furthermore, even if we did somehow identify and breed a wheat variety that truly lacked all celiac toxicity, how could we guarantee that a spontaneous gene mutation or other evolution of the cultivar from one generation to the next (such as hybridization with a toxic variety grown in an adjacent field) didn't reintroduce a known or new toxic form of gluten?

Guaranteeing integrity of celiac-safe wheat

Last year more than 541 million acres of the Earth's surface were planted in wheat. I don't think I'm at all going out on a limb when I say that we'd never see the entirety of world wheat production replaced with celiac-safe wheat. That means that celiac-safe wheat would need to coexist in a world of toxic wheat. This introduces an overwhelming number of concerns.

You'd need agricultural fields dedicated to growing celiac-safe wheat, plus measures put in place to ensure that rogue toxic wheat doesn't infiltrate the crop. And you'd have to implement an impressively robust chain of custody to maintain the integrity of a celiac-safe crop of wheat from field through processing and into flour, products, and/or the dinner table. Remember: celiac-safe wheat will look, bake, and taste like its toxic sisters.

Imagine tracking the life of a celiac-safe crop of wheat through a dedicated flour mill that won't cross-contaminate the batch with conventional wheat, then getting that flour to food product companies and onto supermarket shelves, and then clearly identifying and differentiating those celiac-safe wheat products for consumers (not to mention the regulatory hurdles!).

This is a rabbit hole that goes deeper and deeper the more you think about it. The daunting prospect is enough to make your head spin.

Wait for Celiac-Safe Wheat? Thanks, But No Thanks.

Gluten-based foods processed to remove the gluten are one thing (and a subject best left for another post), but as you can see, inherently celiac-safe wheat that still has gluten in it is an ongoing area of research, if still a distant possibility for consumers at the very best. It's an admirable line of scientific inquiry, but I for one won't be holding my breath. For certain I'll watch ongoing developments with keen interest—for the love of the science, if nothing else—but when it comes to my health and our kitchen at home, wheat has no place, and that isn't likely to change anytime soon, if ever in my lifetime.

What about you? Would you eat celiac-safe wheat and bake with its flour? Do you long for its taste? For the doughy elasticity of true gluten in your baking? I'd love to hear your opinions...

–Pete

1 comment:

didier Fesquet said...

Excellent overview of the problem. I think that if one day non toxic gluten free wheat is developed ..it might remains a lab curiosity .
Sadly the tools are here now to inactivate the gliadin toxic epitope (once a full inventory as been made), it works in wheat , the so called crisp/cas9 allows to surgically edit the wheat genome . ..
Didier