Consumption of nitrate containing vegetables and the risk of chronic kidney disease: Tehran Lipid and Glucose Study

Abstract

Background: There is growing evidence regarding the potential properties of nitrate-rich foods in development of chronic diseases. In this study, we investigated the association of nitrate-containing vegetables (NCVs) and the risk of chronic kidney disease (CKD). Methods: We evaluated 1546 eligible adult participants of the Tehran Lipid and Glucose Study (TLGS), at baseline (2006–2008) and again after 3 years (2009–2011). Dietary intake was collected using the validated semi-quantitative food frequency questionnaire. Nitrate-containing vegetables and its categories including high-, medium-, and low-nitrate vegetables were defined. Estimated glomerular filtration rate (eGFR) and CKD were defined. Association between NCVs and CKD in the cross-sectional phase and the predictability of NCVs consumption in CKD occurrence were assessed using multivariable logistic regression models with adjustment for potential confounders. Results: Mean dietary intake of energy-adjusted NCVs was 298.0 ± 177.3 g/day. Highest compared to the lowest tertile of NCVs was accompanied with a significantly lower mean eGFR (76.6 vs. 83.3, mL/min/1.73 m², p < 0.001) and a higher prevalence of CKD (21.7 vs. 9.9%, p < 0.001). At baseline, higher intake of high-NCVs was associated with a 48% higher chance of having CKD (OR = 1.48, 95% CI = 1.05–2.13). After 3 years of follow-up, there was no significant association between consumption of total NCVs and its categories with the occurrence of CKD. Conclusion: Considering the lack of association between high-NCVs intakes and the risk of CKD in prospective analysis, additional research is recommended to clarify possible effect of nitrate intakes from vegetables on kidney function.

Keywords:

• Chronic kidney diseases
• fruits and vegetables
• nitrate

Acknowledgements

We thank the Tehran Lipid and Glucose Study participants and the field investigators of the Tehran Lipid and Glucose Study for their cooperation and assistance in physical examinations, biochemical evaluation and database management. We thank Ms N Shiva for critical editing of the English grammar and syntax of the manuscript.

Disclosure statement

The authors declare no conflict of interest.

Funding information

This study was supported by grant no. 121 from the National Research Council of the Islamic Republic of Iran and the Research Institute for Endocrine Sciences of Shahid Beheshti University of Medical Sciences.