Crunching into a lusciously sweet slice of watermelon is a marvellous way to while away a spring or summer afternoon. The amazing news is that sumptuous fruit is also good for you and in fact may help to keep your blood pressure down.
The ingredient that has this power to relieve the pressure is called citrulline. Watermelon is the richest dietary source of citrulline an amino acid that in the body is converted to l-arginine. In turn this l-arginine is converted to nitric oxide which is involved in opening the blood vessels and keeping blood pressure down.
For this study people with early stage high blood pressure were given six grams daily of citrulline extracted from watermelon for a period of six weeks. After that time there was improved blood vessel function and reduced blood pressure in all of the subjects.
The question is how much watermelon would you have to consume to get that much citrulline? According to the US Department of Agriculture the watermelon with the highest citrulline content is the yellow-fleshed variety. You would need around 210g of this to get approximately six grams of citrulline. The more common red-fleshed watermelon unfortunately contains significantly less and you would need to eat around 800g of the red flesh to get your six gram citrulline dose.
The good, or bad, news depending on how you look at it, is that the watermelon rind is very high in cutrulline. So if you feel like sitting down to a plate of watermelon rind who knows how much citrulline you might be getting!
Of course, when you eat watermelon you are also getting other nutrients like vitamin A, vitamin B6, vitamin C, and the antioxidant lycopene. All of which makes watermelon one of those unique beasts; a delicious snack that is good for you.