vegetablesA study appearing in the Journal of Nutrition (2005; 135(10): 2468-2472) compared 362 patients with colorectal adenoma to 427 healthy controls. Researchers looked at the diets of the two groups and found an inverse relationship between the amount of folic acid, vitamin B6 and vitamin C in the diet and the risk for colorectal adenoma. Vitamin D and beta carotene levels had an inverse association with adenoma risk. The benefit from beta carotene was enjoyed by non-smokers, but not smokers.