Among the most important permissive factors [in gut permeability] are vitamin D and omega-3 fatty acid deficiencies.

AutoImmune Diseases - https://t.co/QPTNKdeNJx

— Wejolyn 🇺🇸 (@Wejolyn) December 10, 2021

Known to initiate and increase intestinal permeability.  They actually separate the intestinal cells.  He explains that 

The most important and common initiating causes are the gliadin protein of wheat and related proteins of other grains, including the zein protein of corn, and the casein beta A1 protein of dairy. Among the most important permissive factors are vitamin D and omega-3 fatty acid deficiencies. 

That last point about vitamin D and omega-3 fatty acid deficiencies was valuable.