Children with chronic kidney disease (CKD) are generally encouraged to limit their fruit and vegetable intake to avoid hyperkalemia. However, according to Amina El Amouri and colleagues, there is little data with direct evidence to support this widespread practice; furthermore, the resulting restriction of fiber exposure is associated with deprivation of potential health benefits associated with fiber exposure.
The researchers conducted an analysis to examine the associations between dietary potassium intake, fiber intake and serum potassium in pediatric CKD. The results were reported online in Pediatric Nephrology [doi:10.1007/s00467-021-05365-5].
Longitudinal analysis examined data from a 2-year prospective multi-institutional study that followed children with CKD at 3-month intervals. At each visit, 24-hour recalls and 3-day food records were used to assess dietary potassium and fiber intake. At the same visit, serum potassium concentrations were determined. Linear mixed models were used to examine the associations between dietary potassium intake, dietary fiber intake, and serum potassium concentrations.
The analysis included data on 52 patients (7 transplant patients; none on dialysis), with a median age of nine years (range: 4-14 years) with an estimated glomerular filtration rate (eGFR) of 49 mL/min/ 1.7m2 (range, 25-68ml/min/1.73m2). For each gram per day of decreased dietary potassium intake, the estimated average daily fiber intake was 5.1 grams lower (95% confidence interval, 4.3-5.9 g/day; P<.001>
In a model adjusted for time point, eGFR, treatment with a renin-angiotensin-aldosterone system inhibitor, serum bicarbonate concentration, and body surface area, there was no association between dietary potassium (P=.40) or dietary fiber (P=.43) with circulating potassium.
In conclusion, the researchers stated that “dietary potassium and fiber intake are closely related, but not associated with circulating potassium levels in pediatric CKD”.