The goal of this randomized, double-blind, placebo-controlled multicenter study is to investigate whether the combination of food supplementation with Tonalin® and specific probiotics is a safe and effective add-on to first-line disease modifying treatment (DMT, interferon-beta derivatives as well as glatirameracetate and other glatirameroids) in relapsing remitting MS (RRMS). 100 patients will be randomly assigned in a 1:1 ratio to receive either both food supplements for 48 weeks or to receive placebo in addition to their established first-line disease modifying treatment (DMT). The two randomized groups will be compared concerning the change in volume of T2-weighted hyperintense lesions from baseline to 48 weeks.