The Effect of Low Water Intake on Blood Glucose Measured with a Continuous Glucose Monitor

The number of people with Type II diabetes is rapidly increasing worldwide. Previous studies have shown several factors contribute to the development of Type II diabetes, such as genetics, diet, and physical activity. Previous laboratory studies have demonstrated adequate water intake may slightly reduce post-prandial blood glucose. However, none have focused on the relationship between water intake and blood glucose excursions in a free-living situation. PURPOSE: This study aimed to examine the effect of low water intake on glucose regulation in a free-living situation using continuous glucose monitoring. METHODS: In a counterbalanced cross-over fashion, three participants were randomly assigned to a high-water intake (HWI; 3.7L for men, 2.7L for women) or low-water intake (LWI; (1L for men, 0.7L for women) condition for six days followed by a two-day washout period of ad libitum water intake. The participants then transitioned to the other condition for the following six days. Caloric intake and macronutrient intake were identical between both six-day periods. During the study, participants wore a Freestyle Libre 3 continuous glucose monitoring system and a GeneActiv sensor to monitor real-time blood glucose and physical activity. Urine samples were collected upon waking and between 3:00 and 5:00 p.m. and analyzed for urine-specific gravity (USG). RESULTS: USG during HWI and LWI was 1.014 ± 0.001 and 1.024 ± 0.004, respectively. The mean blood glucose for HWI and LWI was 97.0 ± 3.1 mg/dL and 98.4 ± 3.1 mg/dL, respectively. CONCLUSION: Thus far, participants have exhibited lower blood glucose during HWI. However, only 3 participants have been completed; therefore, it is inappropriate to draw statistical conclusions. Data collection will continue until 20 participants are completed. The efficacy and feasibility of the water intake protocol have been confirmed.