Abstract
Objectives
Many studies have examined the beneficial effects of watermelon flesh on metabolic diseases, yet fewer studies have investigated the effects of watermelon rind. While normally discarded, rind consumption not only reduces food waste but contains fiber (pectin) and healthful bioactive compounds such as citrulline. This study examined the effects of watermelon rind consumption on postprandial glucose, satiety and bowel movements. It was hypothesized that consumption of blenderized watermelon juice with rind would lower postprandial glucose, increase satiety and improve bowel movement habits.
Methods
In a double-blind randomized crossover study, 21 participants (age 26.3 ± 5.7 y, BMI 22.6 ± 2.8 kg/m2) consumed one cup (8 fl. oz) of blenderized watermelon juice with or without rind. A visual analogue scale was used to measure satiety at baseline, immediately after, 20, 40, 60 and 90 minutes post juice consumption. Blood glucose was measured at baseline, 20, 40, 60 and 90 minutes post juice consumption. Bowel movement questionnaires were administered two days before and after each trial.
Results
Both blenderized watermelon juices (with and without rind) increased satiety with more fullness in watermelon juice with rind (P < 0.05). Watermelon juice with rind also stabilized blood glucose levels in comparison to watermelon juice (P < 0.001). No significant differences between the two trials for bowel movements were found, but no evidence of constipation or discomfort was presented among the participants.
Conclusions
These results suggest that watermelon juice with rind has favorable effects on postprandial glucose and satiety levels but no effect on bowel movements. Therefore, further research into the benefits of watermelon rind is important and could offer potential clinical applications and disease prevention.
Funding Sources
NUTR 302L Advanced Nutrition Laboratory San Diego State University and National Watermelon Promotion Board (NWPB 19–20).