Lettuce is one of the oldest vegetables and probably originated in India or Central Asia. According to the writings or Herodotus, lettuce was served to the Persian kings as far back as the sixth century BC. It was a popular Roman food at about the beginning of the Christian era, and in the first century AD a dozen distinctively different varieties were described by Roman writers of the era. There is also evidence that lettuce was grown in China in the fifth century AD.
Columbus may have carried lettuce seeds to the New World, for it was being cultivated in the Bahamas in 1494. It was a common vegetable in Haiti as early as 1565, and Brazil was reported to have cultivated before 1650. The early colonists evidently introduced lettuce into the US, and in 1806 16 varieties were reported growing in American gardens.
Both the English and Latin words for lettuce are based on the heavy, milky juice of the vegetable, which is characteristic of the lettuce family. The primitive forms of lettuce has long stems and large leafs grew at the end of these stems. These closed –packed lettuce heads were well developed in Europe by the 16th century, while the loose common head type of developed later.
Lettuce has become the most valuable truck crop, and 85% of the commercial crop is produced in the west-California, Arizona, Colorado, Washington, Oregon, and Idaho. The northeast and south Atlantic states are also important lettuce growing regions.
Lettuce is available all year, and the peak months are May, June, and July. Although the crisp head and butter head types are the most important from a commercial standpoint, the Cos or Romaine type are bets from a health standpoint, as the sun is allowed to penetrate each leaf. The leaves generally have less of the bitterness that is characteristic of some types of head lettuce. The “leaf” or the “bunching” type of lettuce is distinguished by loose leaves that do not form a head. This type is best for home gardening, as it can be grown in areas where the temperature is too high for successful growing of the other types of lettuce. The stem type lettuce has an enlarged stem and no head. The leaves are not as palpable as the other types of lettuce leaves except when young and tender. The stems are pulled and eaten raw or cooked.
Lettuce of good quality should be fresh, crisp, and tender, and if in head lettuce form, the head should be fairly firm to hard. Lettuce with a well developed seed stem has a bitter flavor.
Leaf lettuce is much richer in iron than head lettuce. We do not advocate using head lettuce in the diet, for it contains little nourishment. It contains significantly lower amounts of vitamins A and C than green Romaine lettuce. The darker green outside leaves contain a much higher proportion of the valuable food elements than the light colored inner leaves. Head lettuce is very gas forming , and really only offers bulk to the intestinal tract. It has an alkaline ash, however, and is not stimulating. Also, it is excellent for those who would like to lose weight. It also has many sleep promoting elements and makes good lettuce juice, which help promote sleep. It tends to slow down the digestive effect of the intestinal tract.
NUTRIENTS IN ONE POUND (head lettuce)
Protein: 3.8 g
Fat: 0.6 g
Carbohydrates: 0.1 g
Calcium: 86 mg
Phosphorus: 78 mg
Iron: 1.6 mg
Vitamin A: 1,710 I.U.
Thiamine: 0.20 mg
Riboflavin: 0.21 mg
Niacin: 0.5 mg
Ascorbic acid: 24 mg