Indole-3-carbinol (I3C), a chemical found in vegetables of the broccoli family, is thought to possess cancer preventive properties.

Indole-3-carbinol appears to work in several ways:

  • Facilitating the conversion of estrogen to a less cancer-promoting form 1-3,6
  • Partially blocking the effects of estrogen on cells 4,6,30
  • Directly killing or inhibiting cancer cells 6
  • Reducing levels of free radicals, which can promote cancer by damaging DNA 5

I3C is found in cruciferous vegetables ( Brassicaplants), such as cabbage, broccoli, brussels sprouts, cauliflower, kale, kohlrabi, and turnips. A typical Japanese diet provides the equivalent of about 112 mg of I3C daily; intake in Western diets is lower.7,8