A simplified inventory method for quantitating dietary sodium, potassium, and energy

During an 8-day observation of the effect of K+ supplementation (80 mEq) on Na+ and K+ balance in a biracial sample of young adults (n = 14), a Food Inventory was developed to monitor dietary Na+, K+, and energy intakes. Urine and stool samples provided electrolyte output measures. The Food Inventory reduced heterogeneity of foods consumed and simplified quantitation. It was self-administered and consisted of 10 preselected foods categories, each containing 24 to 40 food items. Energy was higher for whites and for males (p less than 0.10). Both total Na+ intake and Na+ per 1000 kcal were higher for males. A 1.4 Na+/K+ dietary ratio was observed. After K+ supplementation, Na+ balance was negative; a marked natriuresis occurred, being more consistent for Blacks. With K+ supplementation a positive K+ balance occurred and was more evident in Blacks. Significant positive correlations of daily Na+ and K+ intakes with output were observed with higher correlation for K+ than Na+. This dietary assessment method can be useful in metabolic or behavioral studies requiring quantitation of electrolytes and energy.