title: Dietary acid load and metabolic acidosis in renal transplant recipients.
abstract: OBJECTIVE
  Acidosis is prevalent among renal transplant recipients (RTRs) and adversely affects cardiometabolic processes. Factors contributing to acidosis are graft dysfunction and immunosuppressive drugs. Little is known about the potential influence of diet on acidosis in RTRs. This study examined the association of metabolic acid load with acidosis and with cardiovascular risk factors in RTRs and aimed to identify dietary factors associated with acidosis. DESIGN, PARTICIPANTS, SETTING, & MEASUREMENTS: 707 RTRs were included. Metabolic acid load was assessed by measuring 24-hour urinary net acid excretion (NAE; i.e., titratable acid + ammonium - bicarbonate). Acidosis was defined as serum [HCO(3)(-)] < 24 mmol/L. BP and insulin resistance, reflected by hemoglobin A1c, were among cardiovascular risk factors. Diet was assessed with food-frequency questionnaires. Linear regression analysis was applied to investigate association between NAE and acidosis and between dietary factors and acidosis.
  
  
  RESULTS
  Mean age ± SD was 53 ± 13 years; 57% of patients were male. Acidosis was present in 31% of RTRs. NAE was associated with acidosis (serum HCO(3)(-): β=-0.61; serum pH: β=-0.010; both P<0.001). Patients with high intake of animal protein (i.e., from meat, cheese, and fish) and low intake of fruits and vegetables had significantly lower serum HCO(3)(-) and serum pH. No associations were observed between NAE and cardiovascular risk factors, such as hypertension and insulin resistance.
  
  
  CONCLUSIONS
  In addition to conventional factors contributing to acidosis, diet might influence acid-base homeostasis in RTRs. Higher intake of fruits and vegetables and lower animal protein intake is associated with less acidosis in RTRs.
authors.affiliation: Top Institute Food and Nutrition, Wageningen, the Netherlands. e.van.den.berg@umcg.nl
authors.forename: Else
authors.initials: E
authors.lastname: van den Berg
authors.forename: Mariëlle F
authors.initials: MF
authors.lastname: Engberink
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Brink
authors.forename: Marleen A
authors.initials: MA
authors.lastname: van Baak
authors.forename: Michel M
authors.initials: MM
authors.lastname: Joosten
authors.forename: Reinold O B
authors.initials: RO
authors.lastname: Gans
authors.forename: Gerjan
authors.initials: G
authors.lastname: Navis
authors.forename: Stephan J L
authors.initials: SJ
authors.lastname: Bakker
mesh_terms: D000138:Acidosis / Q000209:etiology*; D000328:Adult; D000368:Aged; D001639:Bicarbonates / Q000097:blood; D002318:Cardiovascular Diseases / Q000209:etiology; D003430:Cross-Sectional Studies; D004032:Diet; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016030:Kidney Transplantation; D016014:Linear Models; D008297:Male; D008875:Middle Aged
chemical_list: D001639:Bicarbonates