Sodium and potassium intake measurements: dietary methodology problems

Area of Science:

• Nutritional Science
• Biochemistry
• Public Health

Background:

• Accurate assessment of dietary sodium and potassium intake is essential for public health and managing conditions like hypertension.
• Existing methods for measuring mineral intake, including chemical analysis, calculation from food composition tables, and urinary excretion, have varying degrees of accuracy.

Purpose of the Study:

• To compare the accuracy of different methods for measuring dietary sodium and potassium intake in adolescent females.
• To determine the most reliable method for assessing total mineral intake, considering both analyzed and discretionary sources.

Main Methods:

• Dietary intake was measured using chemical analysis (atomic absorption spectrophotometry) of food samples collected by duplicate analysis.
• Intake was also calculated using a food composition table.
• 24-hour urinary excretion of sodium and potassium was measured using atomic absorption spectrophotometry.

Main Results:

• Average daily total sodium intake was 2.890 g, with analyzed sodium at 2.518 g and calculated sodium at 1.852 g.
• Average daily analyzed and calculated potassium intake were 1.447 g and 1.667 g, respectively.
• Urinary sodium and potassium averaged 2.389 g and 1.118 g per day, respectively, indicating significant individual variation in sodium ingestion.

Conclusions:

• Chemical analysis of total sodium and analyzed potassium in diets and urine are the most accurate methods for determining intake.
• Dietary intake assessment should account for discretionary sodium, which significantly contributes to total intake.
• Regression equations can be utilized to estimate element intakes based on measured values.