Urinary potassium is a clinically useful test to detect a poor quality diet

Area of Science:

• Nutritional Science
• Clinical Biochemistry
• Public Health

Background:

• Poor eating habits significantly impact health outcomes but lack objective assessment in clinical practice.
• Diet quality is a crucial determinant of overall health and disease prevention.
• Identifying reliable biomarkers for diet quality is essential for effective health interventions.

Purpose of the Study:

• To evaluate urinary potassium (K(+)) as an objective biomarker for assessing diet quality.
• To determine the correlation between urinary K(+) excretion and a validated index of diet quality (Recommended Foods Score).
• To investigate the relationship between urinary K(+) levels and key health indicators like BMI, blood pressure, and heart rate.

Main Methods:

• A cohort of 220 kidney stone patients (aged 18-50) provided a 24-hour urine sample for K(+) analysis.
• Participants completed a Food Frequency Questionnaire (FFQ) to calculate the Recommended Foods Score (RFS).
• Urinary K(+) levels were correlated with RFS, BMI, blood pressure, and heart rate, with ROC curve analysis to determine optimal cutoffs.

Main Results:

• Urinary K(+) positively correlated with intake of recommended foods (fruits, vegetables, whole grains) and negatively with non-recommended foods (red meat, fast food).
• A significant positive correlation was found between urinary K(+) and RFS (r = 0.226; P < 0.001).
• Lower urinary K(+) levels (below gender-specific medians) identified individuals with poor diet quality, and were inversely related to BMI, diastolic blood pressure, and heart rate.

Conclusions:

• Urinary potassium (K(+)) serves as a valuable, objective measure of overall diet quality.
• Lower urinary K(+) levels are associated with poorer dietary habits and adverse health metrics.
• Urinary K(+) can be a clinically useful tool for detecting poor dietary patterns and monitoring intervention effectiveness.