Validation Testing Demonstrates Efficacy of a 7 Day Fluid Record to Estimate Daily Water Intake in Adult Men and Women When Compared with Total Body Water Turnover Measurement.
Background: Mean daily water intake from fluids (WATER FL) has proven to be difficult to measure because of a range of nonvalidated data collection techniques. Few questionnaires have been validated to estimate WATER FL against self reported diaries or urinary hydration markers, which may limit their objectivity.Objectives: The goals of this investigation were 1) to assess the validity of a 7 d fluid record (7dFLR) to measure WATER FL (WATER FL 7dFLR) through comparison with WATER FL as calculated by measuring deuterium oxide (D2O) disappearance (WATER FL D2O) and 2) to evaluate the reliability of the 7dFLR in measuring WATER FL.Methods: Participants [n 96; 51% female; mean SD age: 41 14 y; mean SD body mass index (in kg/m2) 26.2 5.1] completed body water turnover analysis over 3 consecutive weeks. They completed the 7dFLR and food diaries during weeks 2 and 4 of the observation. The records were entered into nutritional software to determine the water content of all foods and fluids consumed. WATER FL D2O was calculated from water turnover (via the D2O dilution method) minus water from food and metabolic water. The agreement between the 2 methods of determining WATER FL were compared according to a Bland Altman plot at week 2. The test retest reliability of 7dFLR between weeks 2 and 4 was assessed via intraclass correlation (ICC).Results: The mean SD difference between WATER FL 7dFLR and WATER FL D2O was 131 845 mL/d. In addition, no bias was observed (F[1,94] 0.484; R2 0.006; P 0.488) When comparing WATER FL 7dFLR from weeks 2 and 4, no significant difference (mean SD difference: 71 75 mL/d; t[79] 0.954; P 0.343) and an ICC of 0.85 (95% CI: 0.77, 0.90) was observed.Conclusions: The main findings of this study were that the use of the 7dFLR is an effective and reliable method to estimate WATER FL in adults. This style of questionnaire may be extremely helpful for collecting water intake data for large scale epidemiologic studies.
The Journal of nutrition