Anti-Cancer and Other Biological Effects of a Dietary Compound 3,3′-Diindolylmethane Supplementation: A Systematic Review of Human Clinical Trials

Objective: To systematically review the human clinical trial published studies regarding a dietary compound 3,3'-diindolylmethane (DIM) clinical efficacy towards the prevention and treatment of cancer and other diseases, its bioavailability, safety, and consistency of the results. Methods: An electronic literature search of PubMed database (14), Cochrane Clinical Trials library (3), and Google Scholar (5) from inception to Feb 2020 was conducted. All the in vitro, animal, epidemiological, and review studies of DIM were excluded. Twenty-two randomized or controlled human clinical trials with prospective/retrospective studies published in the English language and that involved DIM intervention on human participants were extracted. Results: DIM has increased estrogen metabolism, decreased androgen-specific antigen, upregulated BRCA1 expression, and increased androgen hormone-binding globulin. This suggests that DIM may have a promising beneficial role as a chemo-preventive supplement for breast and prostate cancers. DIM has shown some clinical efficacy to treat cervical/prostate dysplasia, human papilloma-virus, and warts. Conclusion: The absence of clinical evidence about DIM efficacy to treat prostate or breast cancer patients is the concern as this dietary compound is being advocated as a supplement in the market to treat these disease conditions. The maximum DIM intervention time for breast and prostate cancer patients was 28 days and 12 months, respectively, and most of the prospective trials were targeting DIM biological fate, than adequately addressing DIM efficacy in treating breast or prostate cancer.