For Patients & Caregivers
How It Works
Diindolylmethane (DIM) has anticancer effects but clinical data are limited.
Diindolylmethane is a compound found in cruciferous vegetables including broccoli, cabbage, and cauliflower. It showed anti-inflammatory and anticancer effects in laboratory and animal studies. It was also shown to increase bone mass, which may have implications for patients with osteoporosis. Clinical studies show that DIM may benefit patients with castration-resistant prostate cancer and help reverse cervical intraepithelial neoplasia (abnormal changes in cells on the surface of the cervix). More studies are needed.
Studies suggest that DIM may benefit patients with castration-resistant prostate cancer and help reverse cervical intraepithelial neoplasia.
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
- Central serous chorioretinopathy (CSCR), an idiopathic disease resulting in visual impairment, was reported in a healthy female patient after excessive daily intake of DIM for 2-months. Her symptoms resolved 8 weeks after discontinuing use of DIM.
- Rash with eosinophilia (an increase in the number of eosinophils in the blood, occurring in response to some allergens or drugs) have been reported following use of DIM.
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).
DIM demonstrated anti-inflammatory (16) (17), antiproliferative (16) and chemopreventive (18) effects in vitro and in animal models. It was also shown to increase bone mass (19), which may have implications for patients with osteoporosis.
Limited clinical data indicate that daily supplementation with DIM may benefit patients with castration-resistant prostate cancer by inhibiting androgen receptor (20). But DIM supplementation did not exert any positive effects in women with cervical cell abnormalities (13) although conflicting evidence indicates that it may help reverse cervical intraepithelial neoplasia (21). Additional studies are needed.
A pilot study showed that daily DIM leads to changes in estrogen metabolism in postmenopausal women with a history of early stage breast cancer (4). In a 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
Diindolylmethane (DIM), a metabolite of I3C, can induce apoptosis by modulating the expression of the Bax/Bcl-2. It demonstrated antiproliferative effects in animal and cancer cell models (1). It was also shown to inhibit invasion of normal tissue by cancer cells, and to inhibit angiogenesis in cell culture models (5). DIM induces apoptosis in pancreatic cancer cells (6) and enhances the effect of erlotinib (7). In colon cancer and prostate cancer cells, DIM inhibits CDK activities (8) (9) and induces apoptosis by down regulating 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).
- Central serous chorioretinopathy (CSCR), an idiopathic disease resulting in visual impairment, was reported in a healthy female patient after excessive daily intake of DIM for 2-months. Her symptoms resolved 8 weeks after discontinuing use of DIM (22).
- Rash with eosinophilia and systemic symptoms have been reported 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)