Semester of Graduation

Spring 2020


Master of Science (MS)



Document Type



Impaired endothelial function and microvascular dysfunction are frequently observed in individuals with cardiovascular risk factors such as obesity, insulin resistance, and type 2 diabetes. Reduced nitric oxide (NO) bioavailability is considered to be central to the development of these risk factors. NO can be generated via enzymatic reaction via NO synthase which requires the amino acid arginine. Evidence suggests that the amino acid citrulline is more effective at increasing circulating arginine levels than arginine supplementation alone. The purpose of this pilot study is to determine the potential for citrulline-rich watermelon juice (WMJ) to attenuate the reduction in postprandial endothelial function associated with reduced skeletal muscle microvascular blood flow (MVBF) during hyperglycemia. Seventeen (12 female) non-obese (%Fat Mass= 27.72±7.89%) young adults (Age= 23±3y), with normal or overweight BMI (BMI= 23.48±3.22kg/m2) were enrolled in this study. In a randomized, crossover, double-blinded design, participants supplemented with WMJ or placebo (PLA) (average 12.8, 10-16 days) then underwent an oral glucose tolerance test (OGTT) after an overnight fast. Flow-mediated dilation (FMD) was greater after WMJ compared to PLA following the oral glucose challenge (treatment p=0.038). Baseline oxygen saturation (StO2) was significantly higher in WMJ vs PLA (p=0.031) and the baseline StO2 area under the curve (AUC) was significantly greater in WMJ vs PLA (p=0.03). Our findings suggest that WMJ supplementation is a potentially effective method for improving vascular responsiveness during hyperglycemia via improved skeletal muscle tissue oxygen saturation and improved resting endothelial function.

Committee Chair

Johannsen, Neil