We used a case-control study design (234 carcinomas, 229 high-risk adenomas, 762 low-risk adenomas and 400 controls) to test the association between dietary factors (meat versus fruit, berries and vegetables) genetic polymorphisms in biotransformation genes (GSTM1, GSTT1, GSTP1 Ile105Val, EPHX1 Tyr113His and EPHX1 His139Arg), and risk of colorectal carcinomas and adenomas. The gene discussed is GSTP1; the disease is colorectal carcinoma.