Effects of 12-Week Low or Moderate Dietary Acid Intake on Acid-Base Status and Kidney Function at Rest and during Submaximal Cycling.

Prolonged effects of dietary acid intake on acid-base status and kidney function have not yet been studied in an intervention study in healthy subjects. Dietary acid load can be estimated by calculating the potential renal acid load (PRAL) of foods. Effects of low-PRAL and moderate-PRAL diets on acid-base status and kidney function were investigated during a 12-week exercise training period. Healthy, 20-50-year-old men ( n = 21) and women ( n = 25) participated in the study and were randomly divided into low-PRAL and moderate-PRAL groups. Before (PRE), mid-phase (MID) and after the intervention (POST), the subjects participated in measurement sessions, where a 12-h urine sample and fasting blood samples were collected, and a submaximal cycle ergometer test was performed. Net acid excretion was significantly lower after 12 weeks of the low-PRAL diet as compared to the moderate-PRAL diet, both in men and women. In low-PRAL females, capillary pH and bicarbonate were significantly higher at 75% of VO _2max at POST as compared to PRE. Glomerular filtration rate decreased over the study period in moderate-PRAL men and women. The results of the present study suggest that an acidogenic diet and regularly training together may increase the acidic load of the body and start to impair the kidney function in recreationally active subjects.
Competing Interests: Hannu Pitkänen has a commercial association with Honkatarhat Ltd., Kyröntarhat Ltd. and Mykora Ltd. He accepts full responsibility for the implementation of this study. Other authors declare that they have no conflict of interest.