For years spinach, for its weight, was believed to be the most nutritious green vegetable. Popeye grew muscles eating cans of the stuff. But our knowledge has increased over time and we now know that although spinach contains numerous vital nutrients, and is particularly helpful with problems involving damaged eyesight, within those wonderful glossy leaves lies a chemical called oxalic acid which blocks iron's natural absorption.
If you are looking for the best nutrition per gram then fresh peppery watercress is the perfect ingredient. By weight watercress has more vitamin C than an orange, more calcium than milk and a mere 4oz will provide the full adult daily requirement of potassium. Meanwhile, its massive content of folic acid makes it ideal for pregnant women.
Yet even more exciting are its phytochemicals such as beta-carotene and flavenoids, which combat cancer problems. In fact new studies from the University of Southampton will be published in September this year, on using watercress in the fight against breast cancer. Its high iodine content helps the thyroid function normally. It is known to have a diuretic action helping to draw excess fluid out of the body and its cleansing action helps to improve the complexion. While in India it is chewed to prevent bleeding gums.
Watercress or nasturtium officinale - nasturtium is Latin for nose-twister, referring to the plant's heady scent - is one of our most ancient plants. Its history reaches back to Hippocrates who founded the first European hospital next to natural springs in order to grow the perfect watercress, after attending a "medical school" in Egypt where ancient Pharaohs had served freshly squeezed watercress juice to their slaves to increase productivity.
And in 11th century Persia, Avicenna, a philosopher and scientist, recommended a breakfast of watercress, rocket, lettuce and chicory. Watercress was revered by the Greeks and Romans who thought it cured a deranged mind. The Irish wrote poetry about this wonderful plant, while in the 1800s there was a fashion of drinking the leaves as tea with lemon and sugar. In both world wars, watercress sandwiches at high tea became almost a staple dish.
If you are religious, watercress presents a problem as each leaf will need to be checked for insects and, if picked wild, for water-snails. For this reason it is advisable to buy your bunches from a reputable grower and wash them well.
Once your watercress is clean you can enjoy the peppery flavour. Serve chopped and add to soups and stews just before serving as you would coriander or parsley.
Use watercress as a "bruschetta" topping on slices of rye pumpernickel or real granary bread and layer with smoked mackerel or salmon fillets, orange or grapefruit segments and finely sliced onion with maybe a drizzle of olive oil.
In this way you will obtain Omega 6 and Omega 3, and the orange will improve the absorption of iron from the watercress.
For a light, nutritious lunch make fluffy watercress jackets. For four people, bake a jacket potato per person, preferably in the oven so that the outsides are crispy. Cut in half and scoop out the fluffy middles - careful as they will be very hot. Beat in one 250g container of low-fat cottage or cream cheese. Add the potato middles plus the beaten yolks of 2-4 eggs. Whisk the whites and fold into the mixture plus a bunch of washed, well-chopped watercress. Place under the grill until fluffy middles are golden brown.
Season if required with a little salt and serve.