Anemia is defined as a lower hemoglobin concentration (Hb), red blood cell count (RBC) and/or hematocrit (HCT) per unit volume of peripheral blood than the normal standards for the same age, sex and region. It is generally accepted that in plains areas, adult males with Hb <120g/L, RBC <4.5×1012/L and/or HCT <0.42 and adult females with Hb <110g/L, RBC <4.0×1012/L and/or HCT <0.37 are generally considered anemic. Anemia is one of the most common clinical manifestations. It is not an independent disease, but may be an important clinical manifestation of an underlying or sometimes more complex disease, and once anemia is detected, it is important to identify the cause of its occurrence. The symptoms of anemia depend on the degree of anemia, the speed of its onset, the presence or absence of changes in circulating blood volume, the patient's age, and the compensatory capacity of the cardiovascular system. The general symptoms and signs of anemia are as follows: fatigue, drowsiness, and weakness are the most common and earliest symptoms of anemia. Pale skin and mucous membranes, palpitations after activity, shortness of breath, headache, dizziness, tinnitus, dizziness, lack of concentration, drowsiness, dry skin, dry hair, slow healing of wounds, pale fundus and retinal hemorrhage are also common. Severe patients can develop symptoms such as hypothermia, angina pectoris, heart failure and syncope. Anemia is mainly divided into: iron deficiency anemia, megaloblastic anemia, aplastic anemia and hemolytic anemia. The first two are mainly introduced here. Iron deficiency anemia occurs when the body's iron stores (including in the bone marrow, liver, spleen and other tissues) are depleted and cannot meet the needs of normal red blood cell production. It is a small cell hypochromic anemia. Iron deficiency anemia is a common nutritional deficiency disease with a high incidence in women of childbearing age and infants, and the highest incidence is in children aged 6 months to 3 years, with WHO reporting a 52% incidence in children, 40% in pregnant women, followed by 20% in adult women and 10% in men. Among them, iron deficiency anemia in infants and pregnant women requires prompt attention and treatment. Megaloblastic anemia, also known as nutritional macrocytic anemia, is anemia caused by vitamin B12 and folic acid deficiency or other causes of impaired nuclear DNA synthesis. It is characterized by a typical "megaloblastic transformation" of the bone marrow. It is common in infancy and early childhood, as well as in pregnant women and lactating mothers, but is uncommon in other ages. With the improvement of the standard of living, it is no longer common to see patients with this disease in large and medium-sized cities, but it still occurs in remote rural areas. Nutritional principles: The nutritional principles of iron deficiency anemia: according to the patient's pathological and physiological condition, supplement the relevant nutrients that cause anemia in an appropriate way to correct the anemia. Give a high iron and high protein diet for etiological treatment; giving a high protein diet can promote iron absorption and also provide the raw materials necessary for hemoglobin synthesis in the body; correct poor dietary habits, such as long-term vegetarianism and picky eating. Choose iron-rich foods, such as kelp, nori, fungus, mushrooms, soybean products, meat, poultry, animal liver, etc. Promote the use of iron cookware. Vitamin C supplementation can also promote the absorption of iron. Nutritional principles for megaloblastic anemia: ensure nutritional supply, correct anemia symptoms, and use a diet rich in protein, vitamin B12, folic acid and iron that is easy to digest. Suitable foods: Suitable foods for iron deficiency anemia: 1. Choice of staple foods and legumes Indica rice, japonica rice, millet, sorghum, wheat, barley, gluten, etc. 2, the choice of meat, eggs and milk: animal offal, chicken, rabbit, pork, beef, mutton, carp, crucian carp, shrimp, flatfish, yellow croaker, scallop, snapper, etc., milk and eggs, etc. 3, the choice of vegetables alfalfa, celery, rape, radish, capers, hairy vegetables, kelp, mushrooms, purple cabbage, tomatoes, cabbage, asparagus, bamboo shoots, turnip tassels, amaranth, collapsed vegetables, spinach, etc. 4, the choice of fruit peaches, cherries, kiwi, strawberries, apples, grapes, pineapples, longan, oranges, grapefruit, figs, fresh mulberries, dates, oranges, lemons, prunes, olives, watermelon, plums, lychees, cinnamon meat, persimmons, etc. Suitable food for megaloblastic anemia: 1. Choice of staple foods and legumes The vitamin B12 and folic acid content in wheat and cereals are very little, but wheat flour and japonica rice are rich in protein, and corn and barley are rich in vitamin B. They can be eaten as staple foods often. Soybeans and black beans contain a certain amount of folic acid and can be ground and eaten together with cornmeal, which are the preferred staple foods for patients with megaloblastic anemia due to folic acid deficiency. 2.The choice of meat, eggs and milk Pork liver, lamb liver, chicken liver, pork, beef, lamb, chicken and fish, etc. 3.Choice of vegetables Carrot, asparagus, spinach, rape, cabbage, green pepper, leek, green radish, cucumber, etc. 4, the choice of fruit lychee, bananas, pineapple, olives, apples, peaches, cherries, kiwi, strawberries, tomatoes, etc. Dietary contraindications for patients with iron deficiency anemia: 1, the appropriate level of dietary lipids is beneficial to iron absorption, too high (> 25%) or too low (< 5%) reduces the absorption of iron. 2, avoid drinking tea after meals: tea and persimmons contain tannic acid, encounter iron-containing food can make iron precipitation, affecting the absorption of iron. 3, avoid over-eating cold and rough food affects the function of the spleen and stomach, thus affecting the absorption of iron. Avoid strong wine, strong tea, fatty meat, etc.