How much broccoli is required to get 200 mg of Indole-3-carbinol?
There are numerous estimates of the amounts of I3C and DIM contained in cruciferous vegetables. Most of the amounts are overestimated. This is because in most cases, calculations of available I3C and DIM are based on the measured levels of glucobrassicin in vegetables. This method relies on the erroneous assumption that most if not all of the Indole-3-glucobrassicin is converted to I3C upon chopping, chewing, or juicing. Since most glucobrassicin is actually converted to ascorbigen, the calculated amount of I3C based on this method should be reduced to at least 1/5 of what is suggested.
If ascorbigen is at least five times more prevalent than I3C as literature states and the measured amounts of ascorbigen in vegetable extracts are 2.4-5.5 mg per 100 g fresh weight, the levels of I3C and DIM are low indeed.
By this estimate, 18 kg of broccoli would provide roughly 200 mg of I3C and 20 mg of DIM. Let us know if you require any supporting documentation..