Gluten can increase inflammation in the gut for several reasons:

Gluten: Many grains, especially wheat, rye, and barley, contain gluten. Gluten is a protein that can be difficult for some individuals to digest. In people with celiac disease or gluten sensitivity, gluten triggers an immune response in the small intestine, leading to inflammation and damage to the gut lining. Even in individuals without diagnosed gluten disorders, gluten can contribute to inflammation and digestive discomfort in some cases.

Lectins: Grains contain lectins, which are carbohydrate-binding proteins. Some lectins are believed to be “anti-nutrients” that can irritate the gut lining, interfere with nutrient absorption, and potentially increase intestinal permeability (leaky gut).

Phytic Acid: Grains contain phytic acid, which can bind to minerals like iron, zinc, and calcium in the gut, potentially reducing their absorption. While soaking, sprouting, and fermenting grains can reduce phytic acid content, the GAPS diet eliminates grains entirely.
Impact on Gut Microbiota: Grains can affect the balance of bacteria in the gut (gut microbiota).11 The GAPS diet aims to promote a healthy and diverse gut microbiome by eliminating foods that may feed harmful bacteria and including foods that support beneficial bacteria.

The GAPS diet is based on the theory that a compromised gut lining allows undigested food particles, toxins, and bacteria to enter the bloodstream, contributing to systemic inflammation and various health issues, including neurological and psychological problems. By eliminating grains and other potentially inflammatory and difficult-to-digest foods, the diet aims to heal the gut lining, reduce inflammation, and restore a healthy gut microbiome.