On the one hand, intervention with the combination of 10 probiotic strains together with vitamin B7 in subjects with MDD [47,48] and in people with moderate to severe levels of depressive disorders [40], as well as the L. reuteri NK33 and B. adolescentis NK98 in subjects with subclinical symptoms of depression, anxiety and insomnia [45], improved the plasma levels of proinflammatory cytokines such as IL-6. This evidence concerns the gene IL6 and major depressive disorder.