A lot of useful things from a piece of watermelon - sweet, low calorie, high fiber, nutrient rich - and now, there's more usefulness. Evidence from the pilot study led by food scientists at Florida State University suggests that watermelon can be an effective natural weapon against prehypertension, for signs of cardiovascular or heart disease.
This is the first study of its kind on humans. FSU Assistant Professor, Arturo Figueroa and Professor Bahram H. Arjmandi, found that when the amino acid L-citrulline/L-arginine six grams of watermelon extract given daily for six weeks, an increase in arterial function, and consequently lower aortic blood pressure in all nine subjects who have prehypertension (four men and five menopausal women, ages 51-57).
"We were the first to document an increase in aortic hemodynamics in prehypertension but the opposite result if men and middle-aged healthy women receiving therapeutic doses of watermelon," said Figueroa. "These findings suggest that the 'functional foods' has a vasodilatory effect, and is one that can prevent prehypertension evolving toward full hypertension, a major risk factor for heart attack and stroke.
"Given the evidence produced by the driving force of this preliminary study, we hope to continue their research and involves a group of participants is much larger in the next round," he said.
Why should watermelon?
"Watermelon is a natural source of L-citrulline richest, which is closely related to L-arginine, an amino acid required in the formation of nitric oxide, important in the regulation of vascular tone and healthy blood pressure," said Figueroa.
Once inside the body, L-citrulline is converted into L-arginine. Consuming L-arginine as a dietary supplement is not an option for many adults with hypertension, Figueroa said, because it can cause nausea, gastrointestinal discomfort, and diarrhea.
In contrast, watermelon is very well tolerated. Participants in the Florida State pilot study reported no side effects. And, in adding to the vascular benefits of citrulline, watermelon provides abundant vitamin A, B6, C, fiber, potassium and lycopene, a powerful antioxidant. Watermelon may even help reduce serum glucose levels, according to Arjmandi.
"Cardiovascular disease (CVD) continues to be the leading cause of death in the United States," said Arjmandi. "Generally, Americans have been more concerned about blood cholesterol levels and dietary intake of cholesterol, more than the risk factors of their overall cardiovascular health that lead to CVD, such as obesity and vascular dysfunction characterized by rigidity and thickening of the arteries - the issues where functional foods such as watermelon can help reduce them.
"With functional foods," said Arjmandi, "we mean the food is as scientifically proven to have healthful properties that can prevent disease or, above and beyond the other intrinsically healthy nutrients is also available in it."
Figueroa said the L-citrulline supplementation allows reduction of the dose of oral antihypertensive medications needed to control blood pressure.
"Even better, this can hinder progression from prehypertension to hypertension early," he said.
While watermelon or watermelon extract is the best natural source for L-citrulline, also available in synthetic form in pills, which are used by Figueroa in a previous study on the subject of a younger man. That investigation showed that during the four-week administration of L-citrulline can slow or weaken the increase in aortic blood pressure in response to cold exposure. It is an important finding, said Figueroa, given the incidence of myocardial infarction greater dealing with hypertension during the winter months.
"Individuals with increased blood pressure and arterial stiffness - especially those who are older and those with chronic diseases such as type 2 diabetes - would benefit from L-citrulline, either in the form of synthetic or natural (watermelon)," Figueroa said. "Optimal dose appears to be 4-6 grams per day."
About 60 percent of adults in the United States have prehypertension or hypertension. Prehypertension is characterized by systolic blood pressure between 120-139 millimeters of mercury (mm Hg) over diastolic pressure of about 80-89 mm Hg. "Systolic" refers to blood pressure when the heart contracted, while the "diastolic" blood pressure when the heart reflected is in a period of relaxation and expansion.
The findings of the recent pilot study at Florida State Figueroa described in the American Journal of Hypertension. A copy of the paper ("Effects of Watermelon supplementation on Aortic Blood Pressure and Wave Reflection in Individuals With Prehypertension: A Pilot Study") can be accessed online.
The paper's first author, Figueroa, holds a medical degree, a doctorate in physiological sciences, and a master's degree in sports medicine. He has been a faculty member in the Department of Nutritional Sciences, Food and Training Florida State University since 2004. Co-author and colleague Figueroa, Arjmandi, served as chairman of the department, which is part of the interdisciplinary College of Human Sciences Florida State. Arjmandi also is the author or co-author for an extensive body of research published about the health benefits of prunes and other functional foods.
The authors of the paper Figueroa-Arjmandi in the American Journal of Hypertension, consisting of Marcos A. Sanchez-Gonzalez, Florida State doctoral student in physiology training, and Penelope Perkins-Veazie, a professor of horticulture at the University of North Carolina State.
Source: eurekalert.org
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