Urinary 3,30-diindolylmethane: A biomarker of glucobrassicin exposure and indole-3-carbinol uptake in humans

Naomi Fujioka, Cheryl E. Ainslie-Waldman, Pramod Upadhyaya, Steven G Carmella, Vincent A Fritz, Charlie Rohwer, Yunhua Fan, Diane Rauch, Chap T Le, Dorothy K Hatsukami, Stephen S Hecht

Research output: Contribution to journalArticlepeer-review

34 Scopus citations


Background: Brassica vegetable consumption may confer a protective effect against cancer, possibly attributable to their glucosinolates. Glucobrassicin is a predominant glucosinolate and is the precursor of indole-3-carbinol (I3C), a compound with anticancer effects. However, objective assessments of I3C uptake from Brassica vegetables have not been successful. Methods: We conducted a randomized, crossover trial to test whether 3,30-diindolylmethane (DIM, a metabolite of I3C) excreted in the urine after consumption of raw Brassica vegetables with divergent glucobrassicin concentrations is a marker of I3C uptake from such foods. Twenty-five subjects were fed 50 g of either raw "Jade Cross" Brussels sprouts (high glucobrassicin concentration) or "Blue Dynasty" cabbage (low glucobrassicin concentration) once daily for 3 days. All urine was collected for 24 hours after vegetable consumption each day. After a washout period, subjects crossed over to the alternate vegetable. Urinary DIM was measured using a novel liquid chromatography- electrospray ionization-tandem mass spectrometry- selected reaction monitoring (LC-ESI-MS/MS-SRM) method with [2H2]DIM as internal standard. Results: Urinary DIM was consistently and significantly higher after Brussels sprouts feeding than after cabbage feeding, as evidenced by an average difference of 8.73 pmol/mg creatinine (95% confidence interval, 5.36-12.10; P 1/4 0.00002). Conclusion: We have successfully quantified urinary DIM after uptake of I3C from food, and demonstrated that differences in glucobrassicin exposure are reflected in urinary DIM levels. Impact: Our LC-ESI-MS/MS-SRM method and the results of our study indicate urinary DIM is a measure of I3C uptake from Brassica vegetables, a finding that can be utilized in prospective epidemiologic and chemoprevention studies.

Original languageEnglish (US)
Pages (from-to)282-287
Number of pages6
JournalCancer Epidemiology Biomarkers and Prevention
Issue number2
StatePublished - Feb 2014


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