In other words, wheat actually lets the wolf into the chicken coop and then cries wolf.
Mechanism 2: Homebrew LPS
Wheat contains its own LPS-like molecule, sometimes called LPSw, that has similar effects but admittedly isn’t as potent as the real thing.16, 17 In one study on mice, LPSw was able to promote a bacterial immune response.17
Mechanism 3: ATI's
(No It’s Not a Computer Company)
At the barrier of our gut are a special type of immune cell called dendritic cells. Constantly sampling the contents of our digestive tract, they are the on/off switch of the immune system.18 Think of them as Paul Revere riding back to the immune system yelling “the bacteria are coming!”
Wheat contains molecules that very potently activates dendritic cells called α-Amylase/Trypsin Inhibitors (ATIs).19 They act through TLR-4 on the dendrites. And sorry to those of you who love to say you’re “gluten-free” – ATIs, which exist in many grains, are found in a different part than gluten.
ATI’s are responsible for a long known condition called Baker’s Asthma named so because it was common among people who worked with flour.20
Mechanism 4: Skip the alarm but get the response
TLR-4 and CD14 are not strongly expressed in the gut immune system making it hard to sound the bacterial alarm in the gut.21-23 In an area of the body that’s exposed to bacteria thousands of times each day, an inflammatory response isn’t something we want.21, 22
So it should be concerning to hear that wheat has developed ways of causing the inflammatory response without bothering with TLR-4 or CD14.
The ways wheat does it gets complex. We’ll just touch on them.
First, in several studies, small amounts of gluten were able to flip the dendritic cell’s “on switch” in mice and start an inflammatory response without touching TLR-4.24, 25
Another molecule in wheat (there’s a lot) called wheat germ agglutinin (WGA) can bind and pass right through the gut barrier to interact with immune cells on the other side. WGA then promotes a highly inflammatory response26, 27 including turning dendritic cells on.
Finally, remember all those antigen presenting cells in the gut that avoid sounding the bacterial alarm bells by simply not expressing CD14? Gliadin promotes something called IL-15 which is highly effective at activating APCs that don’t express CD14.28-33
And of a variety of foods tested, gliadin was the only one able to so effectively activate these cells.33
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