Association between food group intakes and metabolic acidosis in patients with non-dialysis-dependent chronic kidney disease

BACKGROUND: Evidence is limited regarding the associations between intakes of specific food groups and metabolic acidosis in patients with chronic kidney disease (CKD). We investigated the association between food group-based intakes and metabolic acidosis in patients with non-dialysis-dependent CKD. METHODS: We used baseline data from a prospective cohort study that recruited adult patients with CKD at three hospitals in Tokyo, Japan. Dietary intake was estimated using a validated diet history questionnaire. We examined the association between intakes of individual food groups and serum bicarbonate levels using multiple linear regression, adjusted for demographic and clinical parameters. We also evaluated the association between food group intakes and metabolic acidosis, defined as a serum bicarbonate level < 22 mmol/L, by multiple logistic regression. RESULTS: Among the 225 eligible patients (median age 72 years, 33.8% women), 43 patients (19.1%) had metabolic acidosis. Intakes of pulses, green/yellow vegetables (including carrots, tomatoes, and green leafy vegetables), other vegetables (including cabbage, radishes, and onions), and dairy products were positively associated with serum bicarbonate levels. Greater intake of other vegetables was associated with lower odds of metabolic acidosis (highest vs. lowest intake: adjusted odds ratio = 0.28, 95% confidence interval: 0.10, 0.79, P = 0.016); however, such associations were not observed for other food groups, including potatoes, green/yellow vegetables, and pulses. CONCLUSIONS: Patients with higher intakes of certain vegetables had lower odds of metabolic acidosis. Further longitudinal studies are warranted to confirm these associations and develop effective dietary measures that optimize the acid-base balance of patients with CKD.