Accumulation of Dietary S‐Methyl Cysteine Sulfoxide in Human Prostate Tissue

Scope Observational studies have associated consumption of cruciferous vegetables with reduced risk of prostate cancer. This effect has been associated with the degradation products of glucosinolates—thioglycosides that accumulate within crucifers. The possible role of S‐methyl cysteine sulfoxide, a metabolite that also accumulates in cruciferous vegetables, and its derivatives, in cancer prevention is relatively unexplored compared to glucosinolate derivatives. The hypothesis that consuming a broccoli soup results in the accumulation of sulfate (a SMCSO derivative) and other broccoli‐derived metabolites in prostate tissue is tested. Methods and results Eighteen men scheduled for transperineal prostate biopsy were recruited into a 4‐week parallel single blinded diet supplementation study (NCT02821728). Nine men supplemented their diet with three 300 mL portions of a broccoli soup each week for four weeks prior to surgery. Analyses of prostate biopsy tissues reveal no detectable levels of glucosinolates and derivatives. In contrast, SMCSO is detected in prostate tissues of the participants, with significantly higher levels in tissue of men in the supplementation arm. SMCSO was also found in blood and urine samples from a previous intervention study with the identical broccoli soup. Conclusion The consequences of SMCSO accumulation in prostate tissues and its potential role in prevention of prostate cancer remains to be investigated. S‐Methyl Cysteine Sulfoxide (SMCSO) is metabolized by gut bacteria to bioactive products but is also found intact in human plasma urine, and prostate tissue following consumption of a broccoli soup.