The connection between human health and environment Human health has a close connection with disease and environment, and food is an important link between human body and environment. The human body obtains nutrients through food intake, and at the same time, it also brings in factors unfavorable to health from food intake, and diet is a necessity for human body every day, and it has a long-term and long-lasting influence on human body. Therefore, it is of great significance to reduce the risk factors of cancer and increase the protective factors against cancer from the aspect of diet in order to prevent cancer. The relationship between diet and cancer Research shows that environmental factors account for about 80% of all cancer-inducing factors, and about 35% of them are related to diet. The relationship between diet and cancer occurs mainly in two aspects: 1, diet or its additives in carcinogenic substances in the pollution, such as certain and food-related molds produced by toxins, preservation of food with nitrite and nitrate is a strong carcinogen nitrosamines precursors, cooking and processing of food formed when some mutagen, such as charcoal smoked meats when the formation of benzo(a)pyrene, a large number of sweeteners and some food coloring agents, Flavoring agents and preservatives have carcinogenic effects. Certain chemicals and hormone derivatives used to promote the growth of livestock and poultry may also have potential cancer-promoting effects, and agricultural pesticides and industrial pollutants are increasingly entering the food chain through soil and water supply. 2. The lack, excess or imbalance of certain nutrients in the diet. How to eat a healthy diet 1, advocate eating a variety of foods, to include the following five categories: the first category for the cereals and potatoes; the second category for animal food; the third category for beans and soy products; the fourth category for vegetables, fruits; the fifth category for the pure calorie food, including animal and vegetable oils, sugar and so on. Pay attention to the coarse and fine mix, eat more natural food, eat less industrial food. 2, to eat more vegetables, fruits and potatoes. 3, to insist on daily intake of milk, beans and their products. 4, often eat fish, poultry, eggs, etc., eat less fat meat and animal oil, at least 1 time a week to eat sea fish, and often eat some kelp. 5, the amount of food should be balanced with the caloric consumption, to maintain a suitable body weight. 6, daily meals should be light, daily salt should not exceed 6 grams. 7, less white wine. You can drink red wine in moderation every day to prevent blood clotting. 8, shopping for food should be selected without pollution, discoloration, change of flavor, in line with health standards. The American Institute for Cancer Research and the World Cancer Research Fund jointly put forward 14 dietary guidelines for cancer prevention: (1) Food supply and eating: consume plant-based food. Nutrient-rich and varied diets, with a focus on foods of plant origin, such as vegetables, fruits, legumes, and less processed cereals. (2) Maintaining body weight: The body mass index of the adult population ranges from 21 to 23, therefore, the individual’s body mass index (body weight kg/height2, kg/m2) should be maintained at 18.5-25 to avoid underweight or overweight, and the increase in body weight in adulthood should be limited to less than 5 kg. (3) Adherence to physical activity: Lifelong adherence to physical activity, if physical activity is low at work, one hour of exercise per day should be performed, or a similar amount of activity should be performed. One hour of more strenuous activity should also be appropriately scheduled each week. (4) Vegetables and fruits: Eat a variety of different vegetables and fruits throughout the year, and the amount should be 400~800g per day. (5) Other plant foods: Eat a variety of starch-rich or protein-rich less processed cereals, legumes, roots and tubers 600~800g per day, which should account for 45%~60% of the total energy, and eat less refined sugar. (6) Alcoholic beverages: Encourage not to drink alcohol or not to drink too much, if you drink alcohol, men are limited to two servings per day, and women are limited to one serving (each serving means 200ml of beer, 100m1 of fruit wine, or 25m1 of strong white wine). (7) Meat: If you eat meat, your daily intake of red meat (e.g. pork, beef and mutton, etc.) should be less than 80g, and it is best to choose fish, poultry or non-poultry animals instead of meat. (8) Total fat and oils: Limit the intake of animal foods containing more fat, consume an appropriate amount of vegetable oils, and the energy of fats and oils should account for less than 15% to 30% of the total energy. (9) Salt and preserved food: Reduce the total intake of salt, limiting it to less than 6g per day for adults, and reduce the use of cooking salt and the preparation of prepared food. (10) l112 Storage: Foods that are susceptible to spoilage should be stored properly to reduce mold. Avoid foods with long storage period and contaminated by molds. (11) Preservation: Perishable foods should be frozen or refrigerated if they cannot be eaten in time. (12) Additives and Pesticide Residues: Establish and monitor limits for food additives, pesticides and residues, and other chemical contaminants in food to ensure that food additives and pesticide residues within specified limits do not have harmful effects. This monitoring should be given particular attention in developing countries. (13) Cooking: Do not eat burnt food. Avoid charring meat and fish, minimize the consumption of food smoked directly over a flame, and encourage the cooking of food at relatively low temperatures. (14) Dietary supplements: Adopt a dietary pattern conducive to reducing cancer risk without the use of dietary supplements. In general, a reasonable diet every day can be summarized as one, two, three, four, five, six, seven, i.e., 1 bag of milk, 2 taels of food per meal (360~500g per day), 3 portions of high protein (such as eggs, beans, fish, etc.), 4 principles of diet (coarse and fine, not sweet, not salty, three, four, five, seven or eight portions of fullness), 500g of fruits and vegetables, 6g of salt (about 2 small flat spoons), and 7 cups of water (including soup). Long-term adherence will be conducive to good health. In addition, cooking methods should pay attention to vegetables should not be boiled for too long, stir-fry taboo oil temperature is too high, to use both animal and vegetable oils, cooking porridge, light vegetables, avoid putting alkali. D. Dietary recommendations for cancer prevention put forward by nutritionists in China 1. Diet meets the requirements of nutritional balance, increases the amount of protein, including a certain amount of animal protein and more adequate legumes. 2. Ensure a certain amount of fresh vegetables, especially dark yellow and green vegetables rich in carotene and vitamin C. 3.Improve dietary habits and cooking methods, advocate fast frying or raw food fresh vegetables to reduce the loss of vitamin C. 4, do not eat mold contamination or burnt food, eat less masked or smoked fried food. 5.Promote the intake of whole grains, to maintain a sufficient amount of micronutrients, dietary fiber and so on. 6, to avoid high salt diet, the daily recommended salt intake of 6g. V. The traditional dietary principles of the Chinese people Although the types and quantities of fruits and vegetables are increasing, the fruits and vegetables eaten by our residents are decreasing. Recently released for the first time, “China’s residents nutritional diet and nutritional status changes” series of reports show that we now eat 10 times more meat than 40 years ago. In fact, the traditional diet of the Chinese people is a light meal, about the traditional dietary principles of the Chinese people have a lot of pithy exposition, such as “diet light, vegetarianism is the main”, “can be a day without meat, not a day without beans”, “Radish, cabbage soup, eat to protect health”, etc. Compared with the high protein, high fat, high calorie diet of Westerners, Chinese people’s intestines and stomachs are more adaptable to vegetarianism. According to the dietary nutrition pyramid recommended by the Chinese Nutrition Society suggests that each person should eat 100 to 200g of fruit and 400 to 500g of vegetables per day, while we now eat 276g of vegetables and 45g of fruit per person per day, far below the recommended standard. China’s famous nutritionist Prof. Li Ruifen said, the Chinese dietary structure is based on plant foods, animal foods as a supplement, the diet is concerned about the acid-base balance, meat and vegetables, if three meals a day, staple foods, side dishes (meat, poultry, fish, eggs, milk), vegetables, fruits, and oil and salt with the proportion of unscientific, excessive proportion of animal food intake, dietary structure is not balanced, and physical activity is reduced, it will make diabetes, high blood pressure, high blood pressure, fat and fat. Will make diabetes, hypertension, fatty liver and other “metabolic syndrome” more and more people.