Fig. 3. The postulated synergistic effects of riboflavin-producing microbiota members such as probiotic lactobacilli and riboflavin.

The beneficial properties consist of riboflavin-mediated effects (as previously described in Fig. 2), probiotic and microbiome-promoting effects such as modulation of immune responses, microbe-microbe interactions and enhancement of the epithelial barrier function¹⁷⁸ and effects mediated by unstable riboflavin intermediates/derivatives leading to MR1-dependent activation of Mucosal Associated Invariant T cells (MR1 = Major Histocompatibility complex class 1 related protein)¹⁸⁷. This figure was created with Biorender.com.