Lettuce contains a lot of beta carotene, antioxidants, vitamins B 1, B6, vitamin E and vitamin C, as well as a lot of dietary fiber and trace elements such as magnesium, phosphorus, calcium and a small amount of iron, copper and zinc. Lettuce can strengthen the digestion and absorption of protein and fat, and improve the blood circulation of the stomach.

Lettuce contains interferon inducer, which can stimulate normal cells to produce interferon, resist virus and improve human immunity. Lettuce contains a substance called protocatechuic acid, which has obvious inhibitory effect on cancer cells, especially in resisting digestive system cancers such as gastric cancer, liver cancer and colorectal cancer.

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Classification of lettuce

1, lettuce

The main feature of lettuce is that its terminal leaves form leaf bulbs. The leaves are entire, serrated or deeply parted, smooth or shriveled, and the terminal leaves form small beads, which are round or eccentric. The main varieties are Hu Da 659, Qianwei 75, Sa Lin Nasi, Beishan No.3, Mamik and Green.

2, wrinkled lettuce

The main feature of wrinkled lettuce is that it does not ball. Basal leaves, oval leaves, long petioles, wavy or deeply divided leaf margins, shriveled leaves, and clustered leaves like big flowers. The main varieties are "Hongfan" purple leaf lettuce, safflower leaf lettuce, green wave lettuce and Dongshan lettuce.

3. Lettuce erecta

The main characteristics of erect lettuce are long and narrow leaves, upright growth, full or serrated leaves, thick leaves, coarse meat and poor flavor. This variety is rare, not widely distributed and rarely cultivated in China. ?

Baidu encyclopedia-lettuce