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This potent anti-cancer anti-oxidant also stimulates the body's natural detoxifying enzyme.

This potent anti-cancer anti-oxidant also stimulates the body's natural detoxifying enzymes.

Health Claims

Indole-3-carbinol is a substance/supplement with antioxidant and cancer-protective effects that also has positive implications for other autoimmune diseases.

What Is It?

Indole-3-carbinol (I3C) is the major anti-cancer substance found in cruciferous (cabbage family) vegetables such as cabbage, broccoli, cauliflower and kale. It is formed and liberated when these vegetables are crushed or cooked and is also available as a dietary supplement found in health food stores.

How Does it Work?

The body breaks down estrogen in several ways. Some estrogen is converted into a substance called 16-alpha-hydroxyestrone, a compound that promotes breast tumours. Another method of breakdown produces 2-hydroxyestrone, which does not stimulate breast cancer cells. Taking I3C supplements shifts the ratio so your body produces more of the "good" estrogen breakdown product and less of the "bad." It does this by increasing the activity of a detoxifying enzyme in the liver called cytochrome P450 1A1.

There are other important anti-cancer mechanisms for I3C. For example, dioxin is a potent cancer-causing pesticide that binds to receptor sites on breast and prostate cells known as the "AH" receptor (aryl hydrocarbon) and stimulates these cells to grow. I3C has been shown to fit into the AH receptor, but instead of sending signals that help cancer grow, it sends powerful signals that stop it. By binding to the AH receptor, I3C also keeps dioxin out of cells.

What Evidence Supports its Use?

Studies have shown that taking I3C as a dietary supplement significantly increases the conversion of estrogen from cancer-producing forms to non-toxic breakdown products. Not surprisingly, I3C is especially protective against breast and cervical cancer. But it also shows promise in the treatment of autoimmune diseases such as lupus, rheumatoid arthritis and multiple sclerosis.

A study on people who worked in a dioxin plant showed that women exposed to dioxin have more than twice the risk of breast cancer. When researchers at Texas A & M University treated breast cancer cells with I3C and dioxin at the same time, dioxin's adverse effects were reduced 90 per cent by using I3C.

In addition to studies showing a protective effect, I3C has shown therapeutic benefit in people with existing cancer. In a double-blind study in women with cervical cancer, 200 or 400 milligrams of I3C daily literally cured half of them within 12 weeks. Was this a placebo effect? Absolutely not, as no subject in the placebo group had complete cancer regression.

In test tube studies conducted at the University of California, I3C inhibited the growth of estrogen receptor-positive breast cancer cells by 90 percent. In comparison, the drug tamoxifen, a popular anti-estrogen, was only 60 percent effective. In estrogen receptor-negative cancer cells, I3C stopped cell growth by about 50 percent, whereas tamoxifen had no significant effect. In studies conducted at the National Cancer Institute, I3C was the best out of 80 anti-cancer candidates, including tamoxifen.

I3C may also have benefit in non-hormone related cancers, including lung cancer. In a study of patients prone to recurrent respiratory papillomas, which are precancerous lesions of the lungs and airways, 33 percent had a complete halt of their papilloma growth and another third showed a reduced papilloma growth rate.

How Should I Take It?

The recommended daily dosage is 200 to 400 mg.


There are no known contraindications.

The Bottom Line

These preliminary results are incredible. Here is a natural compound found in common foods that is not only capable of reversing or halting cancer growth without side-effects, but may also be beneficial in treating autoimmune disease.



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