A 14-Day Double-Blind, Randomized, Controlled Crossover Intervention Study with Anti-Bacterial Benzyl Isothiocyanate from Nasturtium (<i>Tropaeolum majus</i>) on Human Gut Microbiome and Host Defense.

"Conflicts of Interest The study was partly supported by a grant from Repha GmbH, Langenhagen, Germany. Repha GmbH was not involved in the design, conduction, interpretation, or publishing of the results."

"The study was partly supported by a grant from Repha GmbH, Langenhagen, Germany. The article processing charge was funded by the Baden-Württemberg Ministry of Science, Research and Art and the University of Freiburg in the funding program Open Access Publishing. S.P.P. received funding by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—278002225/GRK2202."

"This study is a follow-up to a previously conducted trial registered on the German Clinical Trials Register (DRKS) with the ID DRKS00016548. Details of the design and results of the primary study, which assessed the impact of BITC-containing nasturtium on the lipid regulator prostaglandin E2 in human blood samples, have been already reported in []. In the present study, we focus on the analysis of secondary parameters. Briefly, the study was conducted as a double-blind, monocentric, controlled, randomized crossover intervention. Subjects were all female, between 20 and 45 years of age, healthy, and non-smokers. Exclusion criteria were acute and chronic diseases, acute gastric/intestinal ulcers, acute kidney inflammation, pregnancy, lactation, intake of antibiotics (acute, during the last three months), known allergy to cruciferous vegetables, or a BMI > 25 and <18.5. Following the protocol, 1.5 g nasturtium plant powder (standardized dried powder of T. majus flowers and leaves, provided by Repha GmbH, Langenhagen, Germany) was freshly mixed with 20 mL of water and consumed by subjects two times per day, which over the 14-day intervention period corresponded to a total intake of 42 g. Verum contained nasturtium with preformed BITC in the amount of 18.87 ± 4.5 µmol, while the amount of BITC in nasturtium used as control was almost negligible (0.07 ± 0.06 µmol). BITC content was analyzed using GC-MS and is described in detail elsewhere []. The subjects were asked to follow their usual dietary habits but excluding foods rich in GLS. In addition to other tests, stool samples were collected from N = 34 subjects at the beginning and end of each intervention phase. No DNA could be isolated from stool samples of 4 subjects due to the low amount. High-throughput 16S ribosomal RNA (rRNA) gene sequencing was performed on N = 30. In the first intervention phase, subjects were randomly assigned to either verum or control, each of which was administered for two weeks. Following a crossover procedure, in the second intervention phase the subjects who had started with the verum sample received the control and vice versa. In between, a wash-out phase of at least two weeks was used to exclude possible carry-over effects. The treatment order was randomized by dividing participants using a random-number generator. Participants documented their diet, medications, unusual exercise, and general well-being on a daily basis."