DIM (diindolylmethane) is a plant compound called an indole, and has been shown to help regulate and promote a more efficient metabolism of estrogen, and an optimal ratio of estrogen metabolites. DIM balances estrogen levels, promoting health and well-being. This powerful phytonutrient is found in broccoli, cauliflower, cabbage and brussels sprouts, unlike other phytonutrients like soy isoflavones, has no hormonal properties in itself.
Studies show it works indirectly by increasing the activity of enzymes that control estrogen production. DIM boosts levels of “good” estrogens called 2-hydroxy estrogens and reduces levels of “bad” estrogens which are 16-hydroxy and 4-hydroxy estrones. Both forms of “bad” estrogen are carcinogens, and studies show that women with elevated levels of 16-hydroxy estrone have a high rate of breast cancer. Men can also benefit from DIM supplementation. There’s evidence that benign prostate enlargement and some types of prostate cancer may be related to a buildup of estrogen in that gland, not testosterone. In overweight men because fat cells convert DHEA and testosterone to estrogen, DIM supplementation can be especially helpful.
Michael A. Zeligs, MD, California physician and researcher, makes the argument that DIM supplementation might improve how the body uses DHEA supplements simply through healthier estrogen metabolism. Pure Diindolylmethane is insoluble and poorly absorbed by the human body. Dr. Zeligs was awarded a U.S. Patent for “absorption-enhanced” Diindolylmethane, making it the only formulation shown in humans to improve estrogen metabolism.
Much of the research summarized here used Dr. Zeligs’ absorption- enhanced formulation, often referred to as bio-available (or “absorbable”) Diindolylmethane. There are over 40 studies in the National Library of Medicine Database which involve DIM. In 2001 alone, seven studies were published. In addition, well-controlled, independently-performed human studies have been completed and are awaiting publication. These include use of DIM showing statistically significant benefits for recurrent breast pain and improvement of cervical dysplasia.
Second, ICZ (indolocarbazole) is not a safe derivative of I3C. ICZ activates the dioxin receptor just like dioxin. ICZ does not block it. It is DIM that blocks this receptor (6). This is one of the key benefits of using a stable DIM supplement.
Third, more is not necessarily better. Having a family of reactive products being generated does not provide broader cancer protection if many of these products also have unwanted side effects. Side effects are tolerable in certain cancer treatment drugs for established cancer but not in nutritional substances meant to prevent cancer in healthy individuals.
Fourth, DIM is not estrogenic or a growth promoter of cancer cells when studied in intact humans or animals. When tested in analogous experiments, I3C failed to prevent the progression of cancer (80,81).
In absorbable DIM, pure (but poorly soluble) DIM is complexed with Vitamin-E TPGS to provide for and enhance DIM’s absorption. Vitamin-E TPGS (Tocophersolan) is a well-known ingredient in foods and pharmaceuticals. It is so safe as to appear on the Generally Regarded As Safe (GRAS) list maintained for ingredients by the FDA. Rarely are dietary supplement ingredients safe enough to appear on this list. Proof of its safety has been established in extensive testing, including testing by the NIH (82). Vitamin-E TPGS is also used to improve the absorption of Vitamin-D (83) and Vitamin-E (84) in infants.
In conclusion, dietary supplementation with diindolylmethane (DIM) from cruciferous vegetables has established an important and effective nutritional approach to increasing the safety of estrogen. The availability of dietary supplements containing DIM provide an important new alternative in preventive nutrition and offer a source of support for the hormonal systems of men and women.
To be effective, phytochemical supplements containing highly insoluble substances like DIM require absorption enhancing formulations. DIM supplementation can be combined with reduced alcohol intake to provide a dietary means of reducing the risk of breast and uterine cancer associated with HRT.(85) The supplemental use of DIM allows women to promote and maintain a safer metabolism of estrogen. This expands the opportunities for women to derive the full preventive health benefits from long term hormonal replacement. DIM also increases the safety of exposure to estrogen derived from DHEA. This supports the rationale for long term supplementation with DHEA by both men and women. Documented, aging-related changes in men support their need for an improved metabolism of estrogen. (86). DIM use by men provides a promising dietary means to minimize the impact of increased estrogen on atherosclerosis and prostate disorders characteristic of andropause.(87). These important benefits for successful aging in men and women all relate to an optimal and safer “estrogen balance”.