Rocket
One of the leafy greens richest in nitrate, and nitrate is what opens your blood vessels.
How to use it
Raw, over the plate after cooking. Through a salad, over pasta, over a pizza as it leaves the oven.
The best version
Wild rocket with narrow, deeply cut leaves tastes of more than the broad cultivated kind. Dark green and dry, not wet in the bag.
How to prepare it
Do not heat it. Wash and spin it dry, because water on the leaf dilutes your dressing and makes the whole thing limp.
What it does
Nitrate from vegetables is converted by bacteria on your tongue and becomes nitric oxide in your body, which relaxes your blood vessels. That is the mechanism by which beetroot juice, across seven trials in 218 people with high blood pressure, brought systolic pressure down by 4.95 mmHg.
Watch out
Those trials used beetroot juice and not rocket. The mechanism has been measured, this leaf has not, and that is a difference worth knowing before you expect anything from it.