Quantifying dietary acid load in U.S. cancer survivors: an exploratory study using NHANES data

BACKGROUND: Diet is an important determinant of systemic pH and acid–base regulation. A frequent consumption of acid-inducing foods (including processed meats and cheese) combined with a low intake of base-inducing foods (such as fruits, legumes and vegetables) increases Dietary Acid Load (DAL), which has been associated with an increased risk for certain cancers. DAL also appears to be of paramount importance in cancer survivors, in whom it was associated with increased mortality and poor overall physical health. Literature on DAL in cancer survivors, however, is scarce and limited to a few studies. METHODS: Using cross-sectional data from the National Health and Nutrition Examination Surveys (NHANES), we sought to quantify DAL in U.S. cancer survivors and contrasted the results to the general population. DAL was estimated using established formulas (Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP)). RESULTS: Our study comprised 19,413 participants, of which 1444 were self-reported cancer survivors. Almost 63% of cancer survivors were female (weighted proportion) with a mean age of 61.75 (0.51) years. DAL scores were consistently higher in cancer survivors (as compared to the general population) after adjustment for confounders in multivariate regression models. These differences, however, were not statistically significant (p = 0.506 for NEAP(F), 0.768 for PRAL(R) and 0.468 for NEAP(R), respectively). Notably, DAL scores were positive throughout (> 0 mEq/d) in cancer survivors, suggesting an acidifying diet. Specific examples include mean PRAL(R) scores > 11 mEq/d in cancer survivors aged 55 years and mean NEAP(F) scores > 50 mEq/d in cancer survivors aged 40–60 years). CONCLUSIONS: The acidifying diet in this sample of cancer survivors warrants caution and requires further investigation. Comparably high DAL scores have been associated with adverse health outcomes and an increased mortality in previous studies in breast cancer survivors. Thus, increased awareness as well as additional clinical trials in this field are urgently warranted.