Did you know that the unassuming broccoli or those mounds of Brussels sprouts may hold the answer to preventing breast cancer?
These types of foods fall into category know as Brassica vegetables, all of which contain a plant compound that has been known to detoxify excess estrogen and work to prevent hormone-related cancers. When you eat these veggies, the chewing process releases plant enzymes, which in turn create a phytochemical known as indole-3-carbinol (I3C).
While I3C has its own merits, we are more interested in its by-product—diindolylmethane (DIM)
Cruciferous vegetables such as broccoli, bok choy, kale, cauliflower, cabbage and Brussels sprouts contain high amounts of glucosinolates (SGS), a class of sulphur-containing compounds that break down into isothiocyanates.
Cancer-fighting isothiocyanates work by eliminating potential carcinogens from the body and by enhancing the way tumor-suppressor proteins are copied.
One particular compound derived from glucosinolate—indole-3-carbinol (I3C)—is especially important. I3C molecules combine with each other in the stomach to form several different end products, one of which is 3,3-diindolylmethane, or DIM.
DIM is best known for preventing and treating breast cancer. However, it also inhibits inflammation, blocks tumors’ ability to establish their own blood supply, arrests the growth of cancer cells in the lab and redirects estrogen metabolism toward anti-cancer metabolites and away from metabolites that actually promote breast cancer.
Getting your DIM from fresh, organic cruciferous vegetables is ideal, but for reliable protection, you may need to take DIM in supplemental form.
During estrogen metabolism, the most potent form of estrogen (estradiol) is converted into estrone. Estrone then can convert into a 'good' estrone metabolite—or a 'bad' estrogen metabolite. The good metabolite is then converted into two other 'good' metabolites which have been shown to inhibit the growth of malignant tumors.
The 'bad' metabolite however (16-alpha-hydroxyestrone) has been strongly associated with cancer growth.
This is where DIM comes in. Research has shown that when DIM is ingested, it not only encourages its own metabolism, but that of estrogen. While it is not an estrogen or even an estrogen-mimic, its metabolic pathway exactly coincides with the metabolic pathway of estrogen. When these pathways intersect, DIM favorably adjusts the estrogen metabolic pathways by simultaneously increasing the good estrogen metabolites and decreasing the bad estrogen metabolite.
Research confirms this action. In a study, researchers took urine samples from 34 healthy postmenopausal women. They then added broccoli to the women’s diets. After taking another urine sample, researchers found that this dietary change significantly increased the good : bad metabolite ratio.
Increased intake of cruciferous vegetables has been shown to decrease overall cancer risk. A constituent of these vegetables, indole-3-carbinol (I3C), exhibits estrogen-modifying and chemo-preventative activity. Research suggests that DIM is the predominant active agent in I3C and cruciferous vegetables.
I3C has been shown to enhance DNA repair, as well as suppress the proliferation of various cancer cell lines, including breast, colon, prostate and endometrium by targeting various signaling pathways modulating hormonal homeostasis, cell cycle progression and cell proliferation and survival.
When it comes to breast cancer specifically, research shows that DIM has strong anti-proliferative activity in breast cancer cells, meaning it inhibits the growth of cancerous cells. In fact, DIM inhibits the growth of breast cancer cell lines by 60 percent.
DIM induces apoptosis (death) of breast cancer cells via several intricate pathways. Some research even reveals that DIM can enhance the effectiveness of the breast cancer therapy Herceptin by reducing cell viability and eventually causing cancer cells to die.
I3C in particular has been shown to increase the expression of the breast cancer suppression gene and inhibit the activation of estrogen receptors by estradiol, which plays a role in the development of estrogen-enhanced cancers including breast, endometrial and cervical cancers.
This had to do with DIM’s (and I3C) role in the estrogen pathway. In a study, done in the late 90s, researchers looked at how the ratio of good: bad estrogen metabolites affected breast cancer risk. They did this by storing urine samples from women for up to 19 years and compare to the actual outcome over these years. Women with the highest good:bad estrogen metabolite ratio had a 30 percent decreased risk for breast cancer. Time and again, the same results were shown in similar studies.
In another study, Swedish women who ate 1 to 2 servings of Brassica foods a day had a 20 to 40 percent lower risk of breast cancer than those women who ate virtually none.
And it’s not just the breasts that benefit. DIM has also been shown to support ovarian and prostate health. In many animal studies, researchers have shown that DIM inhibits the growth of ovarian cancer cells. DIM also has enhanced the effectiveness of the chemotherapy drug cisplatin.
I3C works in a similar way to inhibit ovarian cancer cells. One cell culture study showed that it’s particularly effective when combined with resveratrol.
When it comes to prostate health, DIM inhibits the binding of dihydyrotestosterone (DHT)—the most potent form of testosterone—to androgen receptors in androgen-dependent human prostate cancer cells. Research also demonstrates that DIM induces cell-cycle arrest and apoptosis in prostate cancer cells as well as decreases levels of prostate specific antigen (PSA).
Finally, clinical studies show that cruciferous veggies also fight lung cancer and colorectal cancer.
DIM seems to be particularly supportive of cervical health. In fact, I3C and DIM not only stop cervical cancer in its tracks, they also can inhibit the HPV (Human papilloma) virus, which is fueled by the “bad” pathway as I3C and the bad metabolite compete for the same estrogen receptor. in human papilloma virus (HPV)-infected cervical cells, resulting in inhibition of estrogen-increased expression of HPV oncogenes.
I3C has cancelled out estrogen’s ability to fuel the spread of cells from papilloma-virus-infected cysts. In mice with impaired immunity, papilloma cysts that formed in HPV-infected tissue developed in 100 percent of control mice, but only in 25 percent of mice fed I3C. In cell culture studies, both I3C and DIM were able to cause cervical cancer cells to die.
Preliminary trials in humans also suggest that I3C supplementation may improve conditions related to human papilloma virus infection, such as cervical intraepithelial neoplasia and recurrent respiratory papillomatosis.
Finally, DIM stimulates the safe metabolic excretion of toxins and reduces the toxicity of certain prescription drugs and environmental chemicals.
Based on the research, the recommended dosage for DIM is 100-200 mg daily. You can also take 500 mg daily of I3C, the precursor to DIM.
Adding plenty of cruciferous veggies to your diet is another great way to get your DIM. Just be sure to eat them raw, as cooking or steaming cruciferous veggies can alter their beneficial properties, however don't overdo it, especially not when you have a thyroid condition.