Cruciferous vegetables, such as broccoli and kale, help protect against some cancers and environmental toxins. Among their beneficial nutrients, indole-3-carbinol (I-3-C) is one of the most important. It helps rid our bodies of toxins, may reduce risk for several cancers, and may even protect against the harmful effects of radiation.
In supplements, I-3-C is also available as DIM (3,3′- diindolylmethane). DIM is a metabolite of I-3-C, meaning that our bodies convert I-3-C into DIM. Both forms have been tested in studies.
Toxins such as bisphenol-A (BPA), found in many plastics, contain chemicals that mimic estrogen. They raise estrogen levels, creating an imbalance and potentially increasing risk for hormone-related cancers, such as breast cancer in women and prostate cancer in men.
In women, toxin-triggered hormonal imbalance can accentuate PMS and contribute to thyroid disorders. The same mechanism can also trigger or increase uncomfortable symptoms of menopause.
In men, some conversion of testosterone to estrogen is normal, but toxins inflate the process, resulting in excess estrogen. This may contribute to an enlarged prostate and increase risk for prostate cancer.
How the Supplements Work
Animal and lab studies show that both I-3-C and DIM stimulate detoxifying enzymes, helping to eliminate toxins and harmful forms of estrogen that can lead to cancer. These nutrients can also stop or slow development of cancer cells. So far, animal and lab studies have shown effects on breast, prostate, cervical, ovarian, pancreatic, colon, and lung cancer cells.
In one animal study, I-3-C prevented or reversed BPA-related prostate damage. In another, I-3-C reduced tobacco-induced lung cancer tumors. And another animal study found that DIM reduces damage from radiation by stimulating DNA repair.
Reversing Cervical Lesions
Human studies have focused mainly on reducing cancer risk. Researchers at Louisiana State University Medical Center-Shreveport tested I-3-C on 30 women diagnosed with abnormal growths on the cervix. Such growths are known as cervical intraepithelial neoplasia (CIN), a condition that can lead to cervical cancer. In the study, published in Gynecologic Oncology, each woman took either a placebo, 200 mg of I-3-C, or 400 mg of I-3-C daily for 12 weeks. Biopsies revealed complete regression among four of eight women who took 200 mg of I-3-C and among four of nine women who took 400 mg. Other women who took the I-3-C supplements saw their risk of developing cancer reduced, but those in the placebo group saw no change.
Reducing Breast Cancer Risk
In a study published in Breast Cancer: Basic and Clinical Research, Canadian researchers tested an I-3-C supplement against a placebo on 96 women. Each capsule contained lignans (beneficial fibers found in plant foods), herbs, and 200 mg of I-3-C. For 28 days, the women took one capsule of either a placebo or the supplement, twice daily. Blood and urine tests, which measured biomarkers of cancer risk, showed that those taking the I-3-C supplements significantly reduced their risk for breast and other estrogen-related cancers.
Improving Genital Health
British researchers tested I-3-C supplements as a treatment for vulvar intraepithelial neoplasia (VIN), a condition marked by lesions on the vulva that is sometimes precancerous. In their study, published in the International Journal of Gynecological Cancer, 12 women with advanced VIN took either 200 or 400 mg of I-3-C daily for six months. Both dosages worked equally well. Benefits included significantly less itching and pain, and smaller lesions.
Supplements designed to assist with hormone balance may contain indole-3-carbinol (I-3-C), DIM, or a combination of the two. One or both may also be combined with broccoli or other cruciferous vegetable extracts, lignans, herbs, or other nutrients known to support hormonal health and detoxification. As a general guide, look for approximately 200 mg per daily serving of I-3-C, DIM, or a combination of the two.
Life ExtensionTriple Action Cruciferous Vegetable Extract has I-3-C and DIM-plus broccoli and cabbage extracts.
Women-Sense EstroSense Hormone Balance, with DIM, can help ease PMS symptoms and painful periods.
Nature’s WayDIM-plus features a patented form of DIM called BioResponse-DIM, which is easier for the body to absorb.