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

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

"Watermelon may not be as organ specific as Viagra but it's a great way to relax blood vessels without any drug side-effects."

He added that eating watermelon could also improve heart health, the immune system and even help people who suffer from obesity and type 2 diabetes.

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

While there are many psychological and physiological problems that can cause impotence, extra nitric oxide could help those who need increased blood flow, researchers found.

Citrulline is found in higher concentrations in the rind of watermelons than the flesh.

Because the rind is not commonly eaten, Dr Patil's team are working to breed new varieties with higher concentrations in the flesh.

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