Plant indoles, also called glucosinolates, found in cruciferous vegetables provide health benefits to humans. Cruciferous vegetables are known for their ability to help reduce the risk of cancer and many chronic diseases. Two such indoles provided by cruciferous vegetables are I3C (Indole-3-Carbinol) and DIM (Diindolylmethane). DIM is not naturally present in these plants. It gets released with the help of enzymes upon crushing of the broccoli, cauliflower, cabbage or Brussels sprouts or during human digestion.1,3 Stomach acid, or HCl, can also aid the joining of two indole 3 carbinols to make diindolylmethane. Lack of HCl will hinder one’s ability to make DIM from I3C.2
Basically, DIM is two molecules of I3C combined together. I3C in a capsule is not shelf stable because it is sensitive to light, heat and moisture. I3C is irritating to the stomach and research tells us that it can have very negative side effects in doses over 300 mg daily such as dizziness and unsteady gait which may be due to nervous system toxicity. One study shows evidence that 90% of orally consumed I3C converts to other compounds. Perhaps it is these other compounds that cause these side effects. One compound I3C converts to is ICZ, or indolocarbazole. This compound causes DNA damage.4 DIM studies show no toxicity when given triple the dose in humans.