Validity of a selective recall method for assessing water intake and its relationship with hydration status

OBJECTIVE: We previously established a descriptive dietary record method that accurately quantifies habitual water intake from food and beverages, to ascertain the relationship between water intake and health. Here, we verified the validity of a selective recall method, which is easy for users to answer and analyze. PATIENTS AND METHODS: Japanese men and women aged 20-44 years (n = 16) and 45-64 years (n = 16) participated over three working days and one non-working day. The day following each of the surveyed days, participants collected their first morning urine for urinalysis and completed a selective recall and descriptive dietary record questionnaire. RESULTS: The two methods of determining water intake were positively correlated (r = 0.94, p < 0.0001). Water intake volumes from non-alcoholic beverages (r = 0.94, p < 0.0001), alcoholic beverages (r = 1.00, p < 0.0001), and food (r = 0.72, p < 0.0001), calculated using the two methods, exhibited strong correlation. No correlation was observed between urinalysis parameters and total water intake. A significant, negative correlation was observed between urine osmolarity and total water intake in men (r = -0.55, p = 0.0011) and women (r = -0.51, p = 0.0032) aged 20-44 years. CONCLUSIONS: Selective recall is a valid method for assessing water intake from food and beverages.