Comparison of estimated water requirements of adults across age groups

Physiological changes associated with age may alter the water requirement of older adults compared to younger adults, e.g., reduced ability to concentrate urine, lower proportion of lean body mass, less physical activity, etc. Water balance studies are based on the principle that healthy individuals will drink the water they need to meet their water requirements. On this basis, the Institute of Medicine has stated that given adequate time for physiological compensation, measurement of ad libitum water intake from all sources can be used as an estimate of an individual's water requirement. The Dietary Reference Intake (DRI) for older adults is based on median total water intake (TWI) for younger adult participants in NHANES III. Also, formulas used to estimate water requirements of individual adults do not take age into account. The purpose of this study is to compare the estimated water requirements of older adults and younger adults by examining TWI of participants ≥19 years of age from the continuous NHANES 2003-2004. The TWI g/kg body weight will be determined from the 24 hour recall by totaling water consumed from dietary sources (food and beverages). ANOVA will be performed to test for differences in TWI g/kg body weight between the age groups of 19-30, 31-50, 51-70, and ≥71. It is expected that the estimated water requirements of older adults will be significantly less than that of younger adults. Such findings would likely justify the development of age-specific DRIs for water and age-adjusted formulas for estimating the water requirements of individuals.