Lettuce is an annual plant of the aster or sunflower family Asteraceae. It is most often grown as a leaf vegetable, but sometimes for its stem and seeds. Lettuce was first cultivated by the ancient Egyptians who turned it from a weed, whose seeds were used to produce oil, into a plant grown for its leaves. Lettuce spread to the Greeks and Romans, the latter of whom gave it the name "lactuca", from which the English "lettuce" is ultimately derived. By 50 AD, multiple types were described, and lettuce appeared often in medieval writings, including several herbals. The 16th through 18th centuries saw the development of many varieties in Europe, and by the mid-18th century cultivars were described that can still be found in gardens. Europe and North America originally dominated the market for lettuce, but by the late 1900s the consumption of lettuce had spread throughout the world.
Generally grown as a hardy annual, lettuce is easily cultivated, although it requires relatively low temperatures to prevent it from flowering quickly.
Lettuce is a good source of vitamin A and potassium, as well as a minor source for several other vitamins and nutrients. Despite its beneficial properties, lettuce when contaminated is often a source of bacterial, viral and parasitic outbreaks in humans, including E. coli and Salmonella. In addition to its main use as a leafy green, it has also gathered religious and medicinal significance over centuries of human consumption.
Lettuce is a good source of chlorophyll and vitamin K. Rich in mineral salts with alkali elements that very dominating. This is what helps keep blood clean, and your body in good health.
Lettuce is rich in lutein and beta-carotene. Also supplies vitamin C and K, calcium, fiber, folate, and iron. Vitamin K helps the blood clot. Other nutrients are vitamin A and B6, folic acid lycopene, potassium, and zeaxanthin. Lettuce contains alkaloids that are responsible for the therapeutic effect.
Although all varieties of lettuce have low calories, but has a different nutritional content. Lettuce as a good source of choline. Romain Lettuce, most nutrient-dense of all varieties and is a good source of vitamins A, B1, B2 and C, folic acid, manganese and chromium. Red lettuce gets red color from a pigment called anthocyanin. These pigments functions as an antioxidant, eliminating free radicals that damage cells. Some researchers found a variety of red lettuce contains flavonoids, which is the powerful antioxidants.
Weight loss. Lettuce is very good for dieters because it is very low in calories, on average only 1-50 per serving. Lettuce is also rich in water, allowing the body to hydrated. The lettuce also contain fiber, which helps digestion and gives a sense of fullness for longer.
Lettuce contains beta-carotene which is the crusader against the disease. Certain diseases such as cataracts, stroke, heart disease, and cancer can be combated by eating lettuce.
According to the American Cancer Institute and the American Cancer Society, foods rich in vitamin A and C may help prevent certain cancers. Lettuce contains both vitamin.
Lettuce contains dietary fiber which can help the intestines move more easily so that helps with digestion. Lettuce is also proven to treat gastric acid disorders, arthritis, cataracts, circulatory problems, and colitis.
Lettuce high in magnesium. This element has an important role in the recovery of tissue, nerves, brain, and muscles. Also contributing to shorten the recovery time. Eating lettuce can accelerate recovery of tired muscles, tissues, and nerves.
Lettuce juice when mixed with oil of roses, and then attached to the forehead, can help relieve headaches so as to ensure restful sleep.
Lettuce is rich in folic acid, which is known to help prevent birth defects in the early stages of pregnancy. Also prevent anemia.
Eating lettuce helps fight insomnia because it contains sleep-inducing substance called lactucarium. It is a mild opiate substances that exist in virtually all types of lettuce.
Lettuce is also believed to contribute to heart health.
Mixed lettuce juice and spinach juice is said for those who bothered by hair loss problems.
Researchers at the University of California shows a series of experiments whose results lettuce has a calming effect on sexual desire, a strong influence on increasing the level of fertility. Although these findings seem controversial, lettuce is often recommended to help men suffering from premature ejaculation.
Folic acid in lettuce helps prevent megaloblastic anemia during pregnancy. This was demonstrated in a series of experiments on lettuce mothers who eat free from nutritional anemia. Eating lettuce also have a major effect on the secretion of the hormone progesterone. Eating lettuce with spinach, asparagus, peas, and cauliflower increasing folic acid or vitamin B from the diet. Approximately 300-500 mcg vitamin is required during the last trimester of pregnancy. Deficiency of this vitamin causes megaloblastic anemia.
Lettuce is one of the vegetables that are most vulnerable to pesticide exposure. Therefore, make sure you wash the lettuce thoroughly under running water before cooking or consumption.
Read More at Wikipedia