Want the viagra effect? Eat watermelons!

According to an Indian American scientist in Texas, watermelon has an ingredient that delivers Viagra-like effects to the body's blood vessels and may even increase libido.

The citrulline, found in the flesh and rind of the fruit, triggers off a compound that helps blood vessels in human body relax -- an effect similar to that of Viagra, Dr Bhimu Patil, director of Texas A&M's Fruit and Vegetable Improvement Centre has found.

When watermelons are consumed in large quantities, the citrulline in it reacts with enzymes in the body. It changes into an amino acid called Arginine, known to benefit the heart, circulatory system as well as the immune system.

"The more we study watermelons, the more we realize just how amazing a fruit it is in providing natural enhancers to the human body," said Patil.

"We've always known that watermelon is good, but the list of its very important healthful benefits grows longer with each study."

Beneficial ingredients in fruits and vegetables are known as phyto-nutrients, naturally occurring compounds that react with the human body to trigger healthy reactions, Patil said.

In watermelons, these include lycopene, beta carotene and citrulline, whose beneficial functions are now being unraveled. Among them is the ability to relax blood vessels, much like Viagra does.

"The citrulline-arginine relationship helps the immune system, heart health and may prove to be helpful for those who suffer from obesity and type 2 diabetes," Patil said.

"Arginine boosts nitric oxide, which relaxes blood vessels, the same basic effect that Viagra has, to treat erectile dysfunction and maybe even prevent it."

While there are many psychological and physiological problems that can cause impotence, extra nitric oxide could help those who need increased blood flow, which would also help treat angina, high blood pressure and other cardiovascular problems.

"Watermelon may not be as organ specific as Viagra," Patil said, "But it's a great way to relax blood vessels without any drug side-effects," the researcher said. The benefits of watermelon don't end there, he said.

Arginine also helps the urea cycle by removing ammonia and other toxic compounds from our bodies.

Citrulline, the precursor to arginine, is found in higher concentrations in the rind of watermelons than in the flesh.

As the rind is not commonly eaten, two of Patil's fellow scientists, are working to breed new varieties with higher concentrations in the flesh.

In addition to the research by Texas A&M, watermelon's phyto-nutrients are being studied by the US Department of Agriculture's Agricultural Research Service in Lane, Oklahoma.

As an added bonus, these studies have also shown that deep red varieties of watermelon have displaced the tomato as the lycopene king, Patil said.

Almost 92 per cent of watermelon is water, but the remaining 8 per cent is loaded with lycopene, an anti-oxidant that protects the human heart, prostate and skin health.