Dietary factors associated with bladder cancer.

It is biologically plausible for dietary factors to influence bladder cancer risk considering that beneficial as well as harmful components of a diet are excreted through the urinary tract and in direct contact with the epithelium of the bladder. However, studies that investigated the association between dietary factors and bladder cancer (BC) risk have largely reported inconsistent results. The macronutrient intake and risk of BC could have yield inconsistent results across studies because of lack of details on the type, source and the quantities of different dietary fatty acids consumed. There is evidence to suggest that consumption of processed meat may increase BC risk. Dietary carbohydrate intake does not appear to be directly associated with BC risk. Even though a large number of studies have investigated the association between fruit/vegetable consumption/micronutrients in those and BC risk, they have yielded inconsistent results. Gender-specific subgroup analysis, details of how fruits and vegetables are consumed (raw vs. cooked), adequate control for smoking status/aggressiveness of the cancer and consideration of genetic make-up may clarify these inconsistent results. There is no strong evidence to suggest that supplementation with any common micronutrient is effective in reducing BC risk. These limitations in published research however do not totally eclipse the observation that a diet rich in fruits and vegetables and low in processed meat along with especially smoking cessation may convey some protective effects against BC risk.