Recently this I09 article about wheat made the rounds and there was a part in it that stood out to me:
According to Alessio Fasano, the Medical Director for The University of Maryland's Center for Celiac Research, no one can properly digest gluten.
"We do not have the enzymes to break it down," he said in a recent interview with TenderFoodie. "It all depends upon how well our intestinal walls close after we ingest it and how our immune system reacts to it." His concern is that the gluten protein, which is abundant in the endosperm of barley, rye, and wheat kernels, is setting off an aberrant immune response.
I am not an expert in the matter, but my understanding is that the very etiology of celiac involves the breakdown of gluten (specifically the gliadin) by tissue transglutaminase, which is definitely an enzyme*.
However, in some instances, TG2 can react with water in preference over an amine, leading to the deamidation of glutamine residues. 118,119 Gluten proteins, the immunological trigger of gluten sensitivity, are glutamine-rich donor substrates amenable to deamidation. TG2 contributes to disease development in at least two ways: ﬁ rst, by deamidating gluten peptides and thereby increasing their aﬃ nity for HLA-DQ2/DQ8, which potentiates the T-cell response, 120,121 and, second, by haptenisation of self-antigens through crosslinking with gliadins. 122 This latter activity has been implicated in autoantibody development (ﬁ gure 4). Activation of TG2 and deamidation of gluten peptides seems to be central to disease development and is now well understood at a molecular level.
In fact, it's my understanding that testing for celiac often involves looking for those Anti-transglutaminase antibodies. So it's an enzyme that normally breaks down gluten and the process has gone haywire. If we have an enzyme able to do this, wouldn't that allow normal people to break down gluten? Am I misunderstanding things?
I do find info that gluten tends to be hard for the human digestive system to break down**
Because human gastric and pancreatic enzymes lack postproline cleaving activity, the abundance of proline residues in gluten renders it highly resistant to complete proteolytic degradation in the human gastrointestinal tract, a feature that is most likely linked to the disease-inducing properties of gluten.
But no evidence that this has negative effects on healthy people since most plant foods contain things we can't break down
*Gluten sensitivity: from gut to brain. Marios Hadjivassiliou, David S. Sanders, Richard A. Grünewald, Nicola Woodroofe, Sabrina Boscolo, Daniel Aeschlimann Lancet Neurol. 2010 March; 9(3): 318–330. doi: 10.1016/S1474-4422(09)70290-X
** Combination Enzyme Therapy for Gastric Digestion of Dietary Gluten in Patients With Celiac Sprue Jonathan Gass, Michael T. Bethune, Matthew Siegel, Andrew Spencer, Chaitan Khosla Gastroenterology 1 August 2007 (volume 133 issue 2 Pages 472-480 DOI: 10.1053/j.gastro.2007.05.028)