Independent and interactive associations of dietary nitrate and salt intake with blood pressure and cognitive function: a cross-sectional analysis in the InCHIANTI study

Abstract

Blood pressure (BP) control is a key target for interventions to reduce cognitive decline. This cross-sectional study explored associations between objective (24-hour urine excretion) and subjective (food frequency questionnaire [FFQ]) measures of dietary sodium and nitrate intakes with cognitive function and resting BP in the InCHIANTI cohort. Baseline data from 989 participants aged >50 years were included. In fully adjusted models, participants with concurrent high nitrate and low sodium (Odds Ratio (OR)=0.49, 95%CI 0.32–0.76, p = 0.001) and high nitrate and high sodium (OR = 0.49, 95%CI 0.32–0.77, p = 0.002) 24-hour urinary concentrations had lower odds of high BP than participants with low nitrate and high sodium concentrations. We found no significant associations between sodium and nitrate intakes (24-hour urinary concentrations and FFQ) and poor cognitive performance. Urinary nitrate excretion was associated with lower BP and results appeared to be independent of sodium intake. Further analyses in longitudinal studies are required to substantiate these findings.

Keywords:

• Dietary nitrate
• salt
• sodium
• cognition
• ageing
• blood pressure
• biomarkers

Ethical approval

The Italian National Institute of Research and Care on Ageing (INRCA) Ethical Committee granted approval for this study. Informed consent was obtained from all subjects involved in the study.

Author contributions

MS conceptualised the study. MS and AMG conducted the analysis and wrote the manuscript. MS and AMG are the guarantors of this work and, as such, had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. All authors contributed to the discussion and interpretation of data, and reviewed/critically edited the manuscript. All authors have read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article [and/or] its supplementary materials. The datasets used and/or analysed during the cur-rent study are available from the corresponding author on reasonable request.

Additional information

Funding

This research was funded by the National Institute for Health Research (NIHR) (16/137/62 – Dementia Prevention and Enhanced Care (DePEC), Newcastle University, United Kingdom), using UK aid from the UK Government to support global health research. The views expressed in this publication are those of the author(s) and not necessarily those of the NIHR or the UK Department of Health and Social Care. The salary of LCB is supported by an NHMRC of Australia Emerging Leadership Investigator Grant [ID: 1172987] and a National Heart Foundation of Australia Post-Doctoral Research Fellowship [ID: 102498].