(1) Leaf vegetables: Chinese cabbages (green and white), amaranths, spinach, shepherd's purse, leeks, celery and caraways are included in this group of vegetables. They are rich in carotin, vitamin C and vitamin B2. Green Chinese cabbage, amaranth, spinach and shepherd's purse are rich in carotin and vitamin

C. For example, spinach contains 3.87 mg % of carotin, and amaranth from Sichuan Province contains 8.98 mg % of carotin. Leaf vegetables also contain minerals such as iron, which is not only rich in content but also easily absorbable. Therefore, they are an important part of the diet of anemic patients, pregnant women and breast-feeding mothers. The contents of protein, carbohydrate and fat are low in leaf vegetables, less than 2 %, 5 % and 0.5 % on average, respectively.

Leaf vegetables also contain folic acid, choline, calcium and phosphorus, but the high content of calcium in amaranth, spinach and bamboo shoots is combined with oxalic acid, making it difficult for the body to absorb. The high content of oxalic acid in vegetables can not only interfere with the absorption of calcium but also disturb the calcification of bones after soluble oxalates in food are absorbed by the body. Therefore, infants, pregnant women and bone fracture patients should not take too many vegetables rich in oxalic acid.

(2) Root and rhizome vegetables: Radishes, Chinese yams, lotus roots, potatoes, taros, sweet potatoes, garlic, green onions, asparagus, lettuce and bamboo shoots belong to this group of vegetables containing different nutrients. The starch in potatoes, taros, lotus roots and sweet potatoes is as high as 15-30 %, and it is 29.5 % in sweet potatoes. The content of carotin in carrots is as high as 3.62 mg %. The contents of protein and fat in this group of vegetables are low, and the protein in potatoes and taros is slightly higher (2 %) than that of other root and rhizome vegetables.

Different from leaf vegetables, many root vegetables can be taken as staple foodstuffs, because they contain a great deal of sugar. Although the content of vitamin C in radishes and asparagus is not rich, the uncooked dishes of these vegetables can also supply lots of vitamin C because it is not destroyed in uncooked vegetables. According to pharmacological studies, the lignin in radishes can produce an anti-cancer effect. In addition, the potassium succinate in carrots can produce a hypotensive effect. The juice of fresh carrots is a health-giving drink.

In brief, vegetables contain small amounts of plant protein and fat, but the content of sugar varies greatly in different vegetables. Fresh vegetables contain various vitamins (vitamin C, vitamin B2 and carotin) and minerals (calcium, phosphorus, iron and potassium). They also contain pectine, organic acids and a large amount of cellulose to stimulate peristalsis of the intestines.

Some vegetables can produce a good therapeutic effect. For example, caraways can promote sweating and eruption of measles because they can promote peripheral blood circulation. The eruption of measles is induced by the promotion of peripheral blood circulation, invasion of viruses into the capillaries of the skin, proliferation of endothelial cells of capillaries and exudation of serum.