Lentil proteins are digested into peptides that may modulate gut microbiota composition, but current evidence is limited and less established than for polyphenols or resistant starch, with no direct demonstration of barrier-related effects.

When lentils are eaten, some proteins break into small pieces called peptides, and some starch resists digestion and reaches the gut. In the colon, bacteria prefer to eat the starch first, using it to make short-chain fatty acids. The peptides provide nitrogen that bacteria use to grow instead of making harmful waste products. This shifts the bacterial community toward species that make beneficial fatty acids and away from species that make toxins. The result is a gut environment with more good bacteria and less inflammation.