There’s a new supplement on the market called, Indole-3-Carbinol. It is great for fighting cancer as well as being an anti viral compound. It consists of the substance found in such vegetables as Cauliflower, Broccoli and Brussel sprouts. You can get it at any health food store.
As always check with your doctor, dietician or nutritionist before taking any supplements as they are not regulated by the FDA.
If you cannot find it locally, Amazon has very reasonable prices.