Description

DIM + Indole 3-Carbinol (I3C)

While cruciferous vegetables supply numerous beneficial compounds, I3C is the real reason that, “eat your broccoli” has always been good nutritional advice. According to a recent article in The Journal of Nutritional Biochemistry, “Mounting preclinical and clinical evidence indicate[s] that indole-3-carbinol (I3C), a key bio-active food component in cruciferous vegetables, has multiple anti-carcinogenic and anti-tumorigenic properties.” Although it may seem obvious that a substance consumed by millions worldwide over thousands of years is inherently safe, scientists have now taken a closer look at this important phytonutrient. Numerous cell culture, animal, and human studies have demonstrated I3C’s safety and tolerability, along with its targeted ability to suppress cancer growth and induce programmed cell death in a variety of tumors, including those associated with breast, prostate, endometrial, leukemia, and colon cancers.

Many scientists consider I3C to be especially valuable in protecting against hormone-dependent cancers—such as certain breast, cervical, and prostate cancers—due to its ability to favorably influence the human body’s balance of estrogens. For example, I3C halts cancer cell growth by interfering with the production of proteins involved in abnormal cellular reproduction, and by promoting the production of tumor-suppressor proteins.

I3C has also been shown to induce apoptosis (programmed cell death) in cancer cells by interfering with the production of cellular products that cancer ordinarily marshals to resist apoptosis.

In the liver and intestinal lining, I3C is believed to enhance the functioning of critical enzyme systems that are responsible for detoxifying the body of harmful, potentially cancer-causing chemicals. Such toxic substances may be ingested in food or drink, or be absorbed through environmental contact.

Newly published research suggests that I3C may also work to prevent cancer by interfering with angiogenesis, a process critical to the body’s defense against cancer. Angiogenesis—the formation of new blood vessels that tumors rely on for nutrients and oxygen—has long been regarded as a major potential target in the battle against cancer. In addition, research shows that I3C also induces breast cancer cells to become more responsive to interferon gamma, an important immune system chemical associated with protecting the body from disease.

How DIM Complements I3C

Many scientists believe that I3C’s beneficial effects are partly driven by one of its principal byproducts, diindolylmethane, or DIM. For instance, DIM has recently been shown to promote production of beneficial interferon gamma by breast cancer cells. According to scientists at the University of California, Berkeley, “This novel effect may provide important clues to explain the anti-cancer effects of DIM because it is well known that [interferon gamma] plays an important role in preventing the development of primary and transplanted tumors.” Recently, scientists working with cell cultures also showed that DIM activates cellular stress response pathways in breast, prostate, and cervical cancer cells. This response mimics the reaction of cells deprived of adequate nutrition, further enhancing the cells’ susceptibility to destruction. In other studies, researchers have shown that both DIM and I3C induce cell death in prostate cancer cells.

Scientists at Wayne State University School of Medicine recently noted: “I3C and DIM affected the expression of a large number of genes that are related to the control of carcinogenesis, cell survival, and physiologic behaviors.”

Like I3C, DIM also stops the growth of new blood vessels that tumors require for their survival and metastasis. This newly discovered anti-cancer activity (anti-angiogenesis) is significant. In research at the University of California, Berkeley, in both cell culture assays and live animal models of cancer, small amounts of DIM dramatically reduced biochemical markers of angiogenesis and significantly impeded the rate of new vessel growth. “This is the first study,” the scientists noted, “to show that DIM can strongly inhibit the development of human breast tumor in [an animal] model and to provide evidence for the antiangiogenic properties of this dietary indole.

Taming the Estrogen Connection

Perhaps the single most important mechanism of action of I3C and DIM is modulating estrogen metabolism. This is because estrogen receptors are present on the surface of virtually every type of tissue in the bodies of both men and women, and are associated with several hormone-dependent cancers. One of the most important applications of I3C and DIM may be in protecting against hormone-induced breast cancer. Epidemiological, laboratory, and animal studies indicate that dietary intake of I3C prevents the development of estrogen-enhanced cancers, including breast, endometrial, and cervical cancers. While estrogen increases the growth and survival of tumors, I3C has been found to cause growth arrest and increased apoptosis (programmed cell death).

Both I3C and DIM help promote healthy metabolism of estrogen by influencing the ratio of beneficial 2-hydroxyestrone to unfavorable 16-alpha-hydroxyestrone. An increased ratio of these estrogen metabolites is associated with a decreased risk of breast and other cancers.