A. The role of dietary factors in the occurrence of tumors The etiology of cancer is extremely complex, and a lot of research data show that: about 35% of cancers are mainly related to frequent smoking and excessive consumption of strong alcohol, including some lung cancers, oral cancers, esophageal cancers, laryngeal cancers and some bladder cancers; about 45% of cancers are related to nutritional factors, which refers to the excessive dietary intake of calories, fats (saturated and unsaturated cholesterol and About 45% of cancers are related to nutritional factors, which are caused by excessive dietary calories and fats (saturated and unsaturated cholesterol and fats) and insufficient nutrients in food (such as vitamin A and dietary fiber, etc.). It is predicted that by rationalizing diet, cancer can be reduced by 1/3, and by reducing smoking and alcohol consumption, cancer can be reduced by another 1/3. The causes of tumors are not yet fully understood, but the popular view is that tumors occur due to both genetic and environmental reasons. Genetic factors mainly affect the sensitivity of the organism to environmental factors. According to the research of American scientists, the main environmental factors and their weights in tumor occurrence are as follows: ① smoking accounts for 30%; ② dietary factors account for 35% on average and their variations range from 10% to 70%; ③ fertility and sexual behavior account for 7%; ④ occupational factors account for 4%; ⑤ alcohol abuse accounts for 3%; ⑥ geographical factors account for 3%; ⑦ environmental and water pollution accounts for 2%; ⑧ drugs and medical factors account for 1%. Many epidemiological findings also suggest that the occurrence of tumors is related to dietary habits. Thus, it can be seen that dietary factors play a very important role in the occurrence of human tumors. The occurrence and development of cancer are mainly in three periods, the initiation period, the pro-cancer period and the malignant progression period. The first two periods are benign stages of tumor growth, and the lesions in this period can be reversed, while improper dietary nutrition can affect tumors mainly in these two periods. Good dietary nutrition not only has potential tumor prevention effects, but also certain nutrients have functions such as antioxidant, inhibiting tumor cell proliferation and stimulating human body to produce interferon, so to a certain extent, it also plays a positive therapeutic role. Nutrition therapy and anti-tumor therapy have the same important status. Currently, the main treatments for tumors are surgery, chemotherapy and radiation therapy. It is found that increasing nutrition of cancer patients will encourage the growth and spread of cancer cells and increase the chance of metastasis, which makes the nutritional treatment of tumor in a dilemma, but after repeated weighing, it is considered that nutritional treatment is still an important aspect of tumor treatment and the basis of other treatments. In the current reality that China generally attaches importance to other treatment methods and ignores nutritional therapy, nutritional therapy for tumor patients should be put in the same important position as anti-tumor therapy. Tumor cells are rapidly expanding and growing cells, which need a lot of nutrients. Tumor cells are bound to compete with normal tissues for nutrition, and in this battle, normal cells are always the losers. Cancer patients, like normal people, will suffer from malnutrition if they do not increase nutrition, which will lower the immunity of the body and seriously affect the recovery of patients. Therefore, it is beneficial for cancer patients to cooperate with high nutrition during treatment. Nutritional therapy benefits the organism more than the tumor. Foreign countries have made nutrition therapy an important part of the whole anti-cancer program. Proper nutritional therapy can not only improve the nutritional status of patients, enhance their immune ability and anti-cancer ability and improve their quality of life, but also improve the tolerance of tumor patients to surgical treatment, reduce or avoid post-surgical infections, enable post-surgical wounds to heal as expected, improve the tolerance of tumor patients to radiotherapy or chemotherapy and reduce their toxic side effects. Our people attach more importance to the role of traditional Chinese medicine and nutritional supplements. In fact, there is no definite evidence to prove that nutrients have direct killing effect on tumor cells, and their main role is to have the effect of enhancing physical and immune functions, and to achieve the effect of inhibiting tumor growth with the immune system in the body. When choosing supplements, the following points should be grasped: (1) Diet should be put in the first place and supplements are secondary. (2) It is not advisable to take “big tonic”. Several kinds of supplements used together or in large doses daily will not only fail to have a good effect, but also lead to the opposite effect. (3) Do not believe that any kind of tonic has the effect of treating tumor. They are always adjuvant therapeutic means. (3) Changes of nutritional status of tumor patients Various tumors and their treatments will affect the nutritional status of patients. Malnutrition is common among tumor patients. The main nutritional problems appearing in tumor patients are: 1. Anorexia and weight loss: they are seen in patients with various tumors or surgery, radiotherapy and other drug treatments. Anorexia is most common in gastrointestinal tumors, especially in esophageal cancer, gastric cancer and colorectal cancer. 2.Metabolic abnormalities in tumor patients: increased energy metabolism, which is generally believed to be 10% higher than normal in tumor patients, weight loss is a common phenomenon in tumor patients, which may be caused by reduced intake due to decreased appetite on one hand, or increased consumption on the other; abnormal carbohydrate metabolism is mainly due to glucose intolerance in many tumor patients; abnormal protein metabolism is manifested in protein The abnormalities of protein metabolism include increased protein conversion rate, increased protein synthesis in liver, decreased protein synthesis in muscle and decreased plasma branched chain amino acids; fat metabolism includes increased lipolysis, decreased serum lipoprotein lipase activity and hyperlipidemia; vitamin metabolism mainly includes decreased vitamin C, vitamin E and other antioxidant vitamins; trace element metabolism includes decreased blood selenium and zinc in tumor patients. Malnutrition in tumor patients is a vicious circle, due to loss of appetite and reduced food intake, resulting in reduced physical activity, general debilitation and reduced digestive and absorption functions, further causing anorexia, which eventually leads to weight loss and general failure and affects prognosis. Malnutrition can be divided into three categories: ① wasting malnutrition: mainly caused by insufficient caloric intake of muscle tissue and subcutaneous fat depletion, characterized by a decrease in body weight and other anthropometric values, while maintaining normal serum protein. ②Protein malnutrition: mainly caused by insufficient or excessive protein intake and normal or high food intake, characterized by visceral protein storage depletion. The main manifestation is the decrease of serum albumin, transferrin, prealbumin and other concentrations, and impaired immune function, while the anthropometric indicators are still normal or even higher than normal. (3) Mixed malnutrition: It is caused by insufficient protein and calorie intake, and is characterized by hypoproteinemia, and all anthropometric indicators are lower than normal. This type is the most serious type of malnutrition, in which both skeletal muscle and visceral protein are decreased, endogenous fat and protein reserves are empty, multiple organ functions are impaired, the incidence of infection and other complications are high, and the prognosis is poor. (2) The purpose of nutritional therapy for tumor is to correct or improve the nutritional status of patients, improve the immune function and anti-disease and anti-cancer ability of the body, and achieve the purpose of “supporting the righteousness and fighting against evil”. 2.To improve the quality of life and avoid anxiety by adjusting the nutritional status of patients, so that patients can be spiritually and psychologically enriched and happy. 3. Nutritional therapy is an indispensable part of the total treatment plan of cancer patients. Nutritional therapy can improve patients’ tolerance to surgical treatment, reduce postoperative infection and accelerate wound healing, as well as improve patients’ ability to tolerate chemotherapy and radiotherapy and reduce the toxic side effects of treatment. (3) Daily nutritional support for tumor patients 1. The nutritional needs of tumor patients include two parts, namely, daily basic nutritional needs and increased nutritional needs due to tumor growth, infection, anemia and treatment, so the supply of various nutrients should be higher than the recommended amount, especially the amount of animal protein. 2. Dairy products: including various forms of dairy products. This type of food is the main source of vitamins A, B and D and calcium, and can also provide a certain amount of protein. 3.Vegetables and fruits: mainly provide vitamins and minerals, especially citrus glutinous is the main source of vitamin C, and dark yellow green vegetables can provide carotene. (4) Nutritional support for surgical patients Surgery is a common method to treat tumors, but at the same time, it must be recognized that surgery brings trauma to the body while treating diseases. If the nutritional status of the body is improved before surgery, it can increase the body’s resistance and tolerance to surgery, reduce postoperative complications and infections, and promote wound healing. Effective postoperative nutritional supply has a positive effect on the early recovery of the organism. Nutritional supplementation before surgery can improve immunity and also promote tumor growth. Research in Shanghai Ruijin Hospital showed that: preoperative nutritional support for gastric cancer patients with energy and amino acid supplementation for 1 week. increased NK cell activity, increased CD4 and CD8, increased tumor cell heteroploidy, increased DNA content, increased S-phase percentage, and increased proliferating cell percentage. For non-gastrointestinal surgery pre-surgical patients diet is low in fat, high in protein, vitamins and minerals. Choose fish, chicken, eggs, milk, soy products rich in high quality protein and fresh fruits and vegetables rich in vitamins and minerals. Patients undergoing gastrointestinal surgery are given a semi-liquid diet with less residue from 2 to 3 days before surgery. A liquid diet is given the day before surgery or an elemental meal is given starting 5 days before surgery. After the patient’s surgery, when the patient can eat, the amount of diet can be gradually increased according to the body condition, and gradually transition from fluid to semi-liquid, soft food and universal food. (V) Nutritional support for chemotherapy tumor patients Chemotherapy is an effective means of tumor treatment, but almost all chemotherapy drugs will cause patients’ loss of appetite, nausea and vomiting to varying degrees, thus affecting patients’ nutritional status. A proper diet can prevent and reduce weight loss and malnutrition brought about by treatment. Studies have found that certain antioxidant nutrients can reduce the adverse effects caused by chemotherapy, so more antioxidant nutrients should be supplemented, such as vitamin A, vitamin C, vitamin E, carotene, and foods rich in trace elements zinc and selenium. The dietary nutrition of chemotherapy patients should be carried out in response to the adverse effects of chemotherapy. The side effects of chemotherapy are mainly manifested in systemic reactions, gastrointestinal reactions, bone marrow suppression and other aspects. The diet of chemotherapy patients should be light, nutritious and easy to digest, with semi-liquid or soft food with less residue, and avoid greasy and indigestible food. In order to prevent or reduce the decline of white blood cells and platelets caused by bone marrow suppression, it is advisable to eat more blood and meat, etc. In terms of cooking, boiling, stewing, steaming and other methods are preferred. Mushrooms such as shiitake, mushroom, monkey head mushroom and fungus have been found to be rich in polysaccharides, which are very effective in improving the cellular immune function of human body. (6) Dietary nutrition for radiotherapy patients Patients often have dry mouth, sore throat, nausea and anorexia during treatment. Especially for malignant tumors of maxillofacial or pharyngeal region, radiotherapy reaction is heavy and can also cause radioactive inflammation in mouth, pharynx and esophagus. Therefore, it is necessary to deal with the problems related to diet according to the different clinical symptoms. For those who have severe reaction to radiotherapy, poor appetite, painful swallowing and ulcers in the mouth, semi-fluid diet or tube feeding nutrition support is recommended. To stimulate appetite, a little more salt can be added to ease the feeling of tastelessness in the mouth, meat can be finely chopped or stewed, and vegetables or fruits can be juiced if they cannot be swallowed. Avoid hot foods such as dog meat, mutton, onion, ginger and spicy stimulating foods. For patients with head and neck radiotherapy, food with more soup, fine and soft, list is the main food. If swallowing is difficult, you can eat some cold food to relieve. Drink more water. Patients with abdominal radiotherapy should have a fine and soft diet and choose more easily digestible foods. Drink plenty of water and have small and frequent meals. Eat less milk, sweets and honey to prevent intestinal discomfort. After radiotherapy, it is advisable to choose a high-protein, high-calorie diet to replenish the energy lost due to the treatment. Choose more lean meat, chicken, fish, eggs, tofu and other foods rich in high quality protein. V. Commonly used nutritional support therapy If the natural diet cannot solve the patient’s problem after surgery or when the disease is serious, the commonly used nutritional support therapy in surgery must be used. The purpose of nutritional support therapy is to prevent and correct malnutrition that may occur or has occurred during the patient’s disease and treatment. Nutritional support therapy includes both enteral and parenteral methods. Enteral nutrition (enteralnutrition) involves the delivery of nutrients required for the body’s metabolism via the mouth and feeding tube. Parenteral nutrition (PN) refers to the provision of complete and sufficient nutrients through the intravenous route for the purpose of maintaining the body’s metabolic requirements. When the patient is fasted and all nutrients are provided through the intravenous route, it is called totalparenteralnutrition (TPN). (i) Tube feeding therapy is characterized by its compliance with human physiology, ease of operation and low cost; maintaining the integrity of intestinal mucosal structure and barrier function; and being the first choice for nutritional support. The preparations used for tube feeding nutrition include two types, namely homogenized meals and elemental meals. The homogenized meal is a variety of natural foods that are often consumed and mixed into a fluid nutritional solution after crushing and processing. The indications of homogenized diet are: patients whose gastrointestinal tract has the function of digestion and absorption but cannot eat by mouth; contraindications of homogenized diet mainly include gastric retention or intestinal obstruction digestive tract activity bleeding intestinal infection, severe diarrhea and shock. Physicochemical characteristics of homogenized diet: the composition is close to the normal human dietary structure, with natural flavor; it can be prepared by oneself, and the nutrient content is difficult to calculate precisely; it is limited by the type of food, and the nutrient content is not comprehensive. It is a kind of dregs-free meal with comprehensive nutrients and clear chemical composition, which can be directly absorbed and used by the intestine without digestion. The composition of the elemental diet is based on the daily dietary nutrient requirement and recommended amount of human body, prepared with hydrolyzed protein, carbohydrate, fat and micronutrients; the characteristics of the elemental diet are clear chemical composition, precise content; no need to digest; easy to dissolve; calorie 1kcal/ml; high osmotic pressure, weak acidity; no lactose; poor palatability, not suitable for oral intake. (ii) Parenteral nutrition provides complete and sufficient nutrients through intravenous route to maintain the metabolic requirements of the body. When the patient is fasted and all nutrients are provided through intravenous route, it is total parenteral nutrition (TPN). The indications for parenteral nutrition are protein-thermal malnutrition, gastrointestinal dysfunction, acute pancreatitis, intestinal obstruction, intestinal fistula, short bowel syndrome, inflammatory bowel disease, high catabolic state, perioperative period, during anti-tumor treatment, low birth weight infants, and those who cannot eat for more than 7 days. Contraindications of parenteral nutrition include: severe water-electrolyte, acid-base imbalance, and shock. The preparation of parenteral nutrition is usually manufactured by professional manufacturers and cannot be prepared by yourself, which can provide the daily nutrient requirement of human body. VI. Common symptoms affecting nutrition therapy and their treatment measures 1. Anorexia: It is one of the most common symptoms in tumor and tumor treatment. In order to reduce anorexia, improvement should be made in psychological and food processing methods. 2.Sluggish taste: small amount and multiple meals, more fresh fruits and vegetables, increasing the color and fragrance of food, and avoiding certain protein foods that may cause off-flavors may partially overcome the adverse effects brought by sluggish taste. 3, dry mouth: appear in the head and neck after radiation therapy, due to the reduction of salivary gland secretion. Juicy diet and fruits can be increased, chewing sugar-free chewing gum, and spicy and sour food should be used with caution. 4.Swallowing difficulty: It is often a complication of head and neck radiotherapy or oral surgery. If the symptoms are not serious, soft food can be used, but fluid is not recommended to avoid aspiration of food into the respiratory tract. If the symptoms are severe, tube feeding or intravenous nutrition is required. 5, abdominal distension: is due to the gastrointestinal tract digestive capacity decreased and food through the prolonged time, but also with the nature of the food intake. Small amount of more meals. Sit up or walk appropriately before and after meals, avoid eating fatty, fried, gas-producing food as well as milk and carbonated beverages. 6, constipation: can be due to lack of dietary fiber, reduced activity and the use of narcotic drugs. Fresh vegetables, fruits, whole grain bread and cereals should be added to the diet, and the amount of fluid intake should be increased, and light laxatives or enemas should be used if necessary. 7. Diarrhea: It can be caused by chemotherapy, abdominal radiotherapy or intestinal surgery. At the beginning, take only liquid to make the intestine rest, gradually increase the dregs-free or less dregs food, and then transition to low-dregs soft food and then to normal diet. Avoid bursts of greasy, spicy, stimulating, too cold and fibrous food. If necessary, drugs are available. 8, esophagitis: caused by chemotherapy or radiation therapy to the head and neck area. It often causes pain and difficulty in swallowing. Gargling or swallowing pain relieving liquid such as lidocaine can relieve pain and irritation, and help to ease the irritation of esophageal mucosa, and if necessary, oral antipyretic and analgesic drugs can be taken to relieve pain. VII. Dietary prevention of tumor Prevention The main aspects of tumor prevention are as follows: reduce the intake of carcinogens and carcinogenic precursors in food, such as aflatoxin, fried and deep-fried food, etc.; pay attention to the balance of dietary structure of intake, balanced diet refers to the diet with complete variety and sufficient quantity of various nutrients and reasonable ratio of various nutrients in the diet consumed by human body; increase the intake of protective substances nutrients, such as Antioxidant nutrients, dietary fiber, protein and calcium, as well as anti-pathogenic foods such as garlic and leeks, and immune-enhancing foods such as fungal foods. The National Cancer Institute of Japan has formulated 12 pieces of advice, which are presented here for your reference in daily life: (1) Pay attention to both taste and nutrition in your diet. (2) Overcome picky eating and partial eating, and do not take the same medicine for a long time. (3) Do not overdo the delicious food, so that the diet is moderate. (4) Do not drink strong alcohol, but also to avoid drinking too much alcohol. (5) Do not smoke, smokers should quit smoking. (6) moderate intake of vitamins A, C, E and dietary fiber. (7) Pay attention to eat less salty or overly hot food. (8) Do not eat burnt food, especially burnt fish and meat. (9) Do not eat moldy food. (10) Avoid excessive exposure to sunlight. (11) Abstain from sex, avoid overworking. (12) Maintain air circulation in the living room and pay attention to body cleanliness.