Poster Topical Area: Dietary Bioactive Components
Location: Hall D
Poster Board Number: 274
Objective: Hypertension is a modifiable risk factor for cardiovascular morbidity and mortality. Previous investigations with watermelon extracts have shown promise for improving blood pressure following six weeks of supplementation. These beneficial effects were attributed to arginine and citrulline, yet circulating levels of these amino acids or other bioactive compounds in watermelon were not quantified. Furthermore, acute effects of watermelon ingestion on blood pressure have not been evaluated. The objective of this pilot study was to assess the bioavailability of lycopene, citrulline, and arginine following a one-time dose of 100% watermelon juice and their subsequent effects on blood pressure in older adult women.
Methods: Women (n=8) ages 60-70 years were asked to consume a 12-ounce serving of 100% watermelon juice after an 8-hour overnight fast. At baseline and two hours after juice consumption, blood was collected and blood pressure measurements were performed according to published guidelines. Pulse pressure, a surrogate estimate of arterial stiffness, was calculated as the numeric difference between mean systolic and mean diastolic blood pressure. Serum levels of lycopene, citrulline, and arginine were assessed using a mass spectrometer interfaced with an ultra-high performance liquid chromatography system.
Results: Ingestion of one 12-ounce dose of 100% watermelon juice resulted in a three-fold increase in circulating lycopene levels (p<0.001); however, no significant differences in amino acids were observed pre- and post-ingestion. Average systolic blood pressure and pulse pressure decreased although decreases did not achieve statistical significance.
Conclusions: Given the decreases in measures of blood pressure albeit non-significant, data from this pilot study suggests the need for further investigation of the absorption kinetics of watermelon bioactives in order to establish a dose-duration effect for improvements in blood pressure.
The University of Alabama