Reducing dietary acid load helps prevent further kidney injury in patients with early-stage chronic kidney disease (CKD) due to hypertension, according to data from the Dietary Acid Reduction and Progression of Chronic Kidney Disease trial (Clinicaltrials.gov, NCT06046924).
Nimrit Goraya, MD, of Baylor College of Medicine in Temple, Texas, and colleagues randomly assigned 153 patients with stage 1 hypertensive CKD to consume fruits and vegetables to reduce dietary acid intake by 50%, oral sodium bicarbonate (0.4 mEq/kg), or usual care. At baseline, patients had macroalbuminuria (200 mg/g or more) and a mean eGFR of 101 mL/min/1.73 m2. Patients with diabetes were excluded from the trial.
Over 5 years, mean acid accumulation was significantly lower in the groups consuming produce or oral bicarbonate compared with the usual care group: -1.2 vs -1.7 vs 5.2 mmoL, respectively, Dr Goraya’s team reported in Kidney International Reports. At 5 years, urinary excretion of albumin, N-acetyl-β-D-glucosamine, and angiotensinogen also were lower in the produce and bicarbonate groups, indicating less kidney injury. Kidney function at 5 years was higher in the 2 intervention groups compared with the usual care group: mean 96.5 and 95.9 vs 92.1 mL/min/1.73 m2.
Most modern diets produce net acid because they contain more animal-based than plant-sourced foods – including in patients with CKD and normal eGFR, the investigators explained. “This trial supports that normal eGFR in patients with CKD does not guarantee against sustained acid accumulation when eating modern acid-producing diets.”
Reducing dietary acid levels with base-producing fruit and vegetable consumption, however, can improve metabolic acidosis as well as preclinical acidosis in patients with CKD, according to the investigators. In the trial, the produce group typically consumed 2 to 4 cups daily of farmers’ market apples, apricots, oranges, peaches, pears, raisins, strawberries, carrots, cauliflower, eggplant, lettuce, potatoes, spinach, tomatoes, and/or zucchini.