Effects of sulforaphane glucosinolates from broccoli seed extract on the immune system of healthy Japanese adults

Background: The Purpose of this study was to investigate the effects of sulforaphane glucosinolate (SGS) from broccoli seed extracts on immune function and common cold symptoms in healthy Japanese adults.Methods: This randomized, placebo-controlled, double-blind, parallel-group comparison study was conducted on Japanese adults who had worse health-related quality of life on the SF-8 and were more likely to catch colds from October 22, 2020 to April 2, 2021.Individuals who agreed to participate in the study were randomly assigned to either the SGS 100 mg/day group or the placebo group (n = 33 each). The intervention lasted 8 weeks. The outcomes of this study were the cumulative and the maximum number of days for which common cold symptoms persisted during the intervention period per subject (primary), and the frequency with which subjects experienced these symptoms per group (secondary). Additionally, the incidence rate of subjects infected with the influenza virus, immune indices, and SF-8 were assessed.Results: Based on a per protocol set, 64 subjects (33 in the SGS group and 31 in the placebo group) were analyzed. After the 8-week interventional period, the cumulative number of days for which common cold symptoms per subject was significantly lower for the SGS group than the placebo group (12.1 ± 13.5 for the SGS group and 20.2 ± 18.2 for the placebo group). The cumulative number of days of common cold symptoms per group was also significantly lower in the SGS group than in the placebo group (400 days in the SGS group and 626 days in the placebo group). No changes attributable to the SGS intervention were observed in the other outcomes. There were no adverse events due to food ingestion.Conclusion: A period of 8 weeks of SGS intake was shown to alleviate the onset of common cold symptoms in healthy Japanese adults who were prone to catching colds and had a low subjective sense of wellness.Keywords: Broccoli, sulforaphane, glucoraphanin, cold symptoms, immunityTrial registration: UMIN-CTR: UMIN000042195.Foundation: Murakami Farm Co., Ltd.