Dietary acid load and risk of kidney cancer: an epidemiologic case-control study

Objective: Recent research studies linked the intake of processed meat and fatty foods to an increased risk of renal cell carcinoma. Fruits and vegetables, on the other hand, may convey protective effects. Dietary acid load (DAL) has been proposed as a potential risk factor for various cancer types within the last years. The present study sought to explore potential associations between this novel risk factor and renal cancer. Patients and methods: A case-control study was performed in 114 cases and 864 age-frequency matched controls (978 patients) through a multi-topic inquiry, including a food frequency questionnaire. DAL was calculated based on two commonly used formulas: Potential Renal Acid Load (PRAL) score and Net Endogenous Acid Production (NEAP) score. Odds ratios (OR) and their 95% confidence intervals were estimated by logistic regression, adjusted for potential confounders. Results: We found no significant statistical associations between DAL and kidney cancer risk. The OR for the highest tertiles of scores were: PRAL (=0.91), NEAP (=1.59), and NEAPr (=0.87). All observed trends were non-significant. Conclusions: Although previous studies showed direct, significant associations between a high DAL and risk of certain cancers, we were unable to observe such an association in the present study. Our results indicate that other dietary components that are not related to alkalizing/acidifying properties might explain the interactions between nutrition and kidney cancer. Since to our knowledge, our study is the first epidemiologic report on DAL and renal cancer risk, and further research is warranted to confirm the present findings.