For Patients & Caregivers
Tell your healthcare providers about any dietary supplements you’re taking, such as herbs, vitamins, minerals, and natural or home remedies. This will help them manage your care and keep you safe.
How It Works
Lab studies suggest diindolylmethane (DIM) has anticancer effects, but clinical data are limited.
Diindolylmethane is a compound found in cruciferous vegetables including broccoli, cabbage, and cauliflower. Laboratory studies suggest anti-inflammatory and anticancer effects, but data in humans are quite limited. A few clinical studies suggest DIM may benefit patients with castration-resistant prostate cancer or help reverse abnormal cervical changes in cells. However, more studies are needed to determine safety and effectiveness, as DIM may affect the levels of certain hormones in the body.
Preliminary studies suggest that DIM may benefit patients with castration-resistant prostate cancer and help reverse cervical intraepithelial neoplasia, but additional studies are needed.
DIM supplementation resulted in changes in estrogen urinary metabolites in post menopausal women with a history of early stage breast cancer.
There is no scientific evidence to back this claim.
Do Not Take If
For Healthcare Professionals
Diindolylmethane (DIM) is a metabolite of Indole-3-carbinol (I3C), a compound found in cruciferous vegetables including broccoli, cabbage, and cauliflower. It is the most studied of all I3C metabolites and is thought to be superior to IC3 as a chemoprotective compound for breast cancer and prostate cancer (3).
However, studies in humans are quite limited. Data suggest daily supplementation with DIM may benefit patients with castration-resistant prostate cancer by inhibiting the androgen receptor (20), but studies are mixed on whether it exerts positive effects in women with cervical cell abnormalities (13) (21). One pilot study suggests DIM may lead to changes in estrogen metabolism in postmenopausal women with a history of early stage breast cancer (4). In an RCT of estrogen receptor-positive breast cancer patients taking tamoxifen, daily DIM promoted an increase in the metabolite ratio of 2-hydroxyestrone (2-OHE1, anti-tumorigenic) to 16α-hydroxyestrone (16α-OHE1, pro-tumorigenic) (25). However, this increase was coupled with a reduction in metabolites from tamoxifen. More research is needed to elucidate the pharmacokinetics and clinical efficacy of tamoxifen when taken with DIM.
Mechanism of Action
In preclinical models, DIM induced apoptosis in pancreatic cancer cells (6) and enhanced effects of erlotinib (7). In colon cancer and prostate cancer cells, DIM inhibits CDK activities (8) (9) and induces apoptosis by downregulating survivin (10) (11). DIM supplementation alters estrogen urinary metabolite profiles in women (4) and has androgen-antagonistic effects (14). It also inhibits prostate cancer cell proliferation and induces apoptosis through Akt activation, NF-KB DNA binding, and androgen receptor phosphorylation (15).
Visual impairment: Central serous chorioretinopathy, an idiopathic disease, occurred in a healthy female patient after excessive daily intake of DIM for 2 months. Symptoms resolved 8 weeks after discontinuing use of DIM (22).
Rash: With eosinophilia and systemic symptoms following use of DIM (23).
Tamoxifen: DIM modulates Phase I metabolism through several CYP isoenzymes, resulting in favorable estrogen metabolism and sex hormone-binding globulin (SHBG) levels. However, one clinical study showed a significant decrease in serum endoxifen, without adversely affecting breast density or SHBG (24). Endoxifen is an active metabolite of tamoxifen during Phase I metabolism, and exhibits higher affinity for ER.