Indole-3-Carbinol (I3C)
I3C is a naturally occurring compound derived from cruciferous vegetables such as broccoli, Brussels sprouts, and cabbage that actively promotes the breakdown of estrogen to the beneficial metabolite, 2-OH. However, modern diets are often deficient in these vegetables. Fortunately, research shows that supplementation with isolated, concentrated I3C promotes 2-hydroxlation of estrogen.64 Therefore, I3C is protective to
estrogen-sensitive tissues and may be beneficial to those with health issues related to estrogen dominance.
The mechanism by which I3C promotes 2-OH formation involves the selective induction of Phase 1 metabolizing cytochrome P450 enzymes (P450-1A1 and P450-1A2), which facilitate the 2-hydroxylation of estrogen.64,65 Through this metabolic role, I3C promotes an increased ratio of 2-OH to 16α-OH and may improve estrogen metabolism in women with poor diets or impaired detoxification.3,64,66 I3C may also reduce the activity of the enzyme required for the 4-hydroxylation of estrogen, thereby decreasing carcinogenic 4-OH formation.