Watermelon Extract Supplementation Reduces Ankle Blood Pressure and Carotid Augmentation Index in Obese Adults With Prehypertension or Hypertension.
Am J Hypertens. 2012 Mar 8. Epub 2012 Mar 8. PMID: 22402472
Department of Nutrition, Food and Exercise Sciences, College of Human Sciences, Florida State University, Tallahassee, Florida, USA.
BackgroundAnkle-brachial index (ABI) and ankle blood pressure (BP) are associated with increased carotid wave reflection (augmentation index, AIx). Oral L-citrulline and L-arginine from synthetic or watermelon sources have reduced brachial BP, aortic BP, and aortic AIx. A directly measured carotid AIx (cAIx) rather than aortic AIx has been proposed as a better measurement of central AIx. We evaluated the effects of watermelon extract on ankle BP and cAIx in individuals with normal ABI and prehypertension or stage 1 hypertension.MethodsAnkle and brachial systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), cAIx, ABI, and heart rate (HR) were evaluated in the supine position in 14 adults (11 women/3 men, age 58± 1 years) with prehypertension or stage 1 hypertension (153 ± 4 mm Hg). Subjects were randomly assigned to 6 weeks of watermelon extract supplementation (L-citrulline/L-arginine, 6 g daily) or placebo followed by a 2-week washout period and then crossover.ResultsAnkle and brachial SBP (-11.5 ± 3.8 and -15.1 ± 2.8 mm Hg), DBP (-7.8 ± 2.3 and -7.6 ± 1.8 mm Hg), and MAP (-9.8 ± 2.6 and -7.3 ± 1.8 mm Hg), and cAIx (-8.8 ± 2.6 %) decreased significantly (P<0.05) after watermelon supplementation compared to placebo. Watermelon supplementation had no significant effect (P>0.05) on ABI and HR.ConclusionsThis study shows that watermelon extract supplementation reduces ankle BP, brachial BP, and carotid wave reflection in obese middle-aged adults with prehypertension or stage 1 hypertension and normal ABI, which may reflect improved arterial function.American Journal of Hypertension (2012); doi:10.1038/ajh.2012.20.