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Abstract: TH-PO809

Association Between Dietary Protein Sources and Gut-Derived Uremic Toxins in Patients on Long-Term Hemodialysis

Session Information

Category: Health Maintenance‚ Nutrition‚ and Metabolism

  • 1400 Health Maintenance‚ Nutrition‚ and Metabolism

Authors

  • Narasaki, Yoko, University of California Irvine, Irvine, California, United States
  • Rhee, Connie, University of California Irvine, Irvine, California, United States
  • Zhao, Yitong, University of California Irvine, Irvine, California, United States
  • Kalantar-Zadeh, Kamyar, University of California Irvine, Irvine, California, United States
  • Lau, Wei Ling, University of California Irvine, Irvine, California, United States
Background

Gut-derived uremic toxins derived from bacterial catabolism of amino acids include indoxyl sulfate (IS), p-cresyl sulfate (PCS) and trimethylamine N-oxide (TMAO). These vascular toxins have been associated with increased risk of cardiovascular events and mortality in chronic kidney disease (CKD). In this study, we examined the association between dietary protein sources and gut-derived uremic toxins in chronic hemodialysis patients using an existing biorepository from the “Malnutrition, Diet and Racial Disparities in CKD” (MADRAD) study.

Methods

Dietary intake was assessed using the Block Food Frequency Questionnaire (FFQ). Serum samples collected within 1 year of FFQ survey date were analyzed for uremic toxins using mass spectrometry. Cross-sectional associations were examined using linear regression models.

Results

Participant age was 54±15 years (mean±SD) and 54% were male, n=154. Dialysis vintage was 4.1±3.3 years, and serum was analyzed 2.7±5.8 months from time of FFQ survey. Caloric intake averaged 985 kcal/day [interquartile range (IQR) 569, 1400] and total protein intake was 42 g/day [IQR 24, 64] with 70% from animal sources [IQR 60, 76]. Average serum toxin levels for IS, PCS and TMAO were 10.6±7.1, 79.5±74.9 and 6.6±4.3 ug/mL respectively, as compared to 0, 1.4 and 1 ug/mL in healthy controls. On unadjusted linear regression analysis, there was a positive association between %plant-based protein intake and higher IS levels (beta coefficient, B = 0.074 with 95% confidence interval [CI] 0.005, 0.143; P=0.03) as well as dietary fiber intake from vegetables/fruits and IS levels (B = 0.677 with 95% CI: 0.215, 1.138; P<0.01). There was a negative association between dairy intake and TMAO (B = -1.473 with 95% CI: -2.620, 0.326; P=0.01) and between total animal protein intake and TMAO (B = -0.022 with 95% CI: -0.043, -0.002; P=0.04). Percent plant vs animal protein intake was not associated with PCS levels.

Conclusion

This hemodialysis cohort study revealed unexpected associations between higher plant-based protein intake and higher levels of circulating uremic toxins. More work is needed to elucidate the dietary sources of gut-derived toxins in the dialysis population.