The lettuce is composed of large overlapped leaves, forming in some cases a sprouting. There are lettuces of different shape, size and colour, either green or red. They may have more or less sawed leaves.
There are many doubts on their origin, although it is known that they were already well-known by the old civilisations. The Romans spread their culture all over the rest of Europe.
There exist multiple varieties of lettuce and every year some new ones are obtained, offering significant improvements as far as production, shape of the heart or resistance to diseases. Some of the most known types are the Roman lettuces, Iceberg, trocadero, etc. New groups like the baby lettuces or the red lettuces have also appeared in the market.
The lettuce is eaten raw, in salads together with tomato and onion, among some other ingredients. It can also be eaten cooked or roasted, although less frequently. It is also consumed in vegetable stews.
It has a low content of nutrients and fat, making it recommendable in slimming diets. It gives some vitamins, like vitamin C and folic acid, and small quantities of phosphorus, potassium, iron and calcium. It is considered to have tranquillizer and sedative properties.
The lettuce has been given tranquillizer and sedative properties for many centuries. Moreover, it is used to treat constipation and exhaustion, and it is a diuretic vegetable.