Association of dietary water intake with body composition and the potential mechanism based on urinary metabolic signatures in Chinese elderly individuals aged 75 years and above

Abstract

With the rising global aging rate, elderly nutrition and health issues are major concerns. Current research focuses on nutrients such as protein and vitamins, while there are limited studies on water intake in the elderly. The aim of this study was to assess whether Chinese people aged over 75 years are meeting the recommended adequate intake (AI) for total water intake and its relationship with body composition. This was done by exploring potential mechanisms through the analysis of urinary metabolites. Water intake and dietary status were collected from 456 community seniors aged over 75 years using a 24-hour water intake and dietary record form. Body composition was determined by bioelectrical impedance analysis (BIA). We found that 16.01% of community seniors reached the AI. The protein, fat-free mass (FFM) and skeletal muscle mass (SMM) levels were all increased in the AI group compared to the <AI group. The increase in TWI was associated with increases in body weight and mineral and decreases in the percentage of body fat (β = 0.170, P = 0.032; β = 1.945, P = 0.023; β = −0.125, P = 0.036). TWI was positively correlated with urine volume (UV) (r = 0.560, P = 0.001) and negatively correlated with 24-hour urine osmolality (Uos) (r = −0.378, P < 0.05). Inadequate water intake led to reduced levels of 22 metabolites (e.g., aspartic acid, L-glutamine, and L-tryptophan). TWI was insufficient among older individuals aged over 75 years in China, impacting their body composition, hydration status, and body metabolism. Therefore, it is suggested to monitor the water intake of elderly individuals and guide them to eat sensibly and drink in moderation to promote their health.