288: Dose-Response Effect of Watermelon Consumption on Ambulatory Blood Pressure In Adults With Pre-Hypertension: A Randomized Controlled Pilot Trial

Introduction

Watermelon (Citrullus lanatus) contains two amino acids, L-citrulline and L-arginine, that boost nitric oxide (NO), a vasodilator involved in regulating blood pressure (BP). Pre-clinical and clinical studies with these amino acids and watermelon extracts support a potential for BP lowering effects. However, there is limited research on the impact of watermelon fruit on BP in humans. Therefore, the primary objective of this study was to assess intake of watermelon fruit flesh (WM) on BP in individuals with pre-hypertension. Secondary outcomes included changes in metabolic markers, lipid profiles, NO levels, L-citrulline and L-arginine concentrations and the L-arginine/ADMA (asymmetric dimethylarginine) ratio.

Methods

Thirty-nine individuals (41±14 years, 31±5 kg/m², mean ±SD) with pre-hypertension participated in this randomized, three-arm parallel (n=12/arm), single-blinded, placebo-controlled, 4-week study. Participants randomly received either a low-dose WM beverage (1 cup, 152 g), a high-dose WM beverage (2 cups, 304 g), or a calorie-matched control beverage daily for 4 weeks. BP was measured using Ambulatory blood pressure monitor on the first and last day of the interventions, and fasting blood samples were analyzed for L-citrulline, L-arginine and ADMA using UHPLC-QQQ-MS. Statistical analyses were conducted using SPSS software.

Results

The mean ambulatory blood pressure on day 28 was 130 ± 3.2 mm Hg for the low-dose WM beverage and 124.9 ± 3.9 mm Hg for the high-dose WM beverage with no significant differences observed compared to control beverage (130.2±3.9 mm Hg, p > 0.05). Additionally, no significant changes were observed in metabolic or vascular biomarkers, such as plasma glucose, insulin, and lipid profiles, or in NO, L-citrulline, L-arginine, and ADMA concentrations (p > 005).

Significance

In contrast to previous studies utilizing concentrated watermelon powders or supplements, our findings did not reveal significant changes in BP following the consumption of fresh watermelon beverages. This discrepancy suggests that the form/concentration of the watermelon components may play a key role in its physiological effects.

Authors: Kanishka Singh, Indika Edirisinghe, Britt Burton-Freeman and Amandeep K. Sandhu