No wonder the locals eat so much of it

We always knew that the sandia was good for you. It contains no saturated fat, is low in sodium and is cholesterol free. Because of its high water content, watermelon is also low in calories.

It is an excellent source of vitamins A, B6 and C as well as potassium and it contains lycopene, a potential antioxidant which may have disease-fighting benefits. Researchers believe lycopene might have a role in the prevention of some diseases, such as forms of cancer and heart disease.

The fruit also contains an amino acid arginine which is good for the heart, the circulatory system and helps maintain the immune system in the body. This substance also helps eliminate ammoniac and other toxic compounds from the body.

Now to add to that, scientists at the University A&M in Texas have discovered that the humble watermelon contains a substance called citulline which relaxes the blood capillaries and therefore has a similar effect to viagra.

Before you rush out to buy a sandia, here is the catch; the cirulline is concentrated in the white part of the watermelon (the part we generally don't eat). So the next stage for the scientists is to work with new varieties of sandia where the cirulline is concentrated in the red flesh rather than the rind.

So, when you next see someone struggling home from the market with a huge green melon, you'll know the reason why!