Wang Mingyong (dietotherapy health expert) is suitable for different cooking methods, such as water-soluble vitamins and minerals, chlorophyll, vitamin C and potassium, but not for high-temperature heating and boiling environment. The longer the cooking time, the more nutrients will be lost. Therefore, the boiling time should be shortened as much as possible to keep the nutrients from losing and maintain the taste of food. At present, the scientific community has found that the three nutrients in food will produce carcinogens as long as they are overheated. Protein will produce heterocyclic amines or heterocyclic amines, oils and fats will produce polycyclic aromatic hydrocarbons, and starch will produce acrylamide and other carcinogens. ◎ Cold raw food: The biggest advantage of raw food is that it can retain more nutrients and eat less calories, which can achieve the effect of losing weight. In addition, fresh fruits and vegetables are rich in water and fiber, which can promote smooth defecation, reduce blood lipid, delay the increase of blood sugar and prevent colorectal cancer. A study by the United States Department of Agriculture found that most fresh fruits and vegetables lose vitamin B and C after being heated and cooked, except carrots, tomatoes and spinach. When carrots are cooked, the antioxidant content increases by about 31%, while when tomatoes are cooked, the vitamin A and C content increase by about 21%, while the vitamin C content decreases by 65%. Uncooked raw food may taste bad, and raw food is mostly cold and may not be suitable for everyone. In addition to organic and pollution-free ingredients, raw food may have problems such as eggs and microorganisms, and it is easy to eat microorganisms and parasites. Therefore, patients with chronic diseases, such as cancer and kidney disease, are not suitable for completely raw food, and can be eaten after scalding. Wang Mingyong (dietotherapy health expert) Different nutrients are suitable for different cooking methods, such as water-soluble vitamins and minerals, chlorophyll, vitamin C and potassium, but not suitable for high-temperature heating and boiling environment. The longer the cooking time, the more nutrients will be lost. Therefore, the boiling time should be shortened as much as possible so as not to lose nutrients and maintain the taste of food. At present, the scientific community has found that the three nutrients in food will produce carcinogens as long as they are overheated. Protein will produce heterocyclic amines or heterocyclic amines, oils and fats will produce polycyclic aromatic hydrocarbons, and starch will produce acrylamide and other carcinogens. ◎ Cold raw food: The biggest advantage of raw food is that it can retain more nutrients and eat less calories, which can achieve the effect of losing weight. In addition, fresh fruits and vegetables are rich in water and fiber, which can promote smooth defecation, reduce blood lipid, delay the increase of blood sugar and prevent colorectal cancer. A study by the United States Department of Agriculture found that most fresh fruits and vegetables lose vitamin B and C after being heated and cooked, except carrots, tomatoes and spinach. When carrots are cooked, the antioxidant content increases by about 31%, while when tomatoes are cooked, the vitamin A and C content increase by about 21%, while the vitamin C content decreases by 65%. Uncooked raw food may taste bad, and raw food is mostly cold and may not be suitable for everyone. In addition to organic and pollution-free ingredients, raw food may have problems such as eggs and microorganisms, and it is easy to eat microorganisms and parasites. Therefore, patients with chronic diseases, such as cancer and kidney disease, are not suitable for completely raw food, and can be eaten after scalding. What foods can't be eaten raw? 1. Soybeans, black beans, red mung beans and other leguminous foods: Raw food can cause nausea, gastrointestinal inflammation, diarrhea and other symptoms because it contains leguminous saponin. 2. Pod food: Kidney beans, kidney beans and pea pods contain trypsin inhibitor, hemagglutinin, etc., which will prevent trypsin from decomposing protein into amino acids, resulting in indigestion, which is not suitable for raw food. 3. Spinach and perilla: It contains a high amount of oxalic acid, and it is easy to hinder the absorption of calcium when eaten in large quantities for a long time; Poor liver and kidney function is more likely to affect liver function and even cause acute renal failure. 4. Grains: contains raw starch and minerals such as calcium phytate and magnesium, which cannot be absorbed by the human digestive system unless cooked. 5. White radish, cruciferous vegetables (such as cabbage, cauliflower, white cauliflower, cabbage, etc.): These nutritious vegetables all contain goiter-causing substances, which are easy to hinder the role of thyroid gland in iodine. If eaten raw for a long time, it may cause goiter, which can be greatly reduced by heating. 6. Drupe: raw walnuts, almonds and peanuts are prone to allergies, so those with allergies are less suitable for raw food. ◎ Cooking method: 1. Steaming: The original molecular structure of the food steamed by steam is less damaged, and the original flavor and nutrients of the food are retained to the greatest extent. However, it should be noted that the time should not be too long, so as not to cause nutrient loss. Many steamed vegetables can be steamed in 3 to 5 minutes, but root vegetables, fish and eggs take longer. If you are in a hurry, you can also cut vegetables into smaller chunks or slices and steam them for 11 to 21 minutes. 2. Boiling: This method can preserve the state of food without increasing too many free radicals. However, nutrients in vegetables (such as vitamin A in carrots) will be lost after being boiled for a long time, and the more broken the food is, the more serious the loss of nutrients will be. The University of Warwick in the United Kingdom studied cruciferous vegetables (broccoli, cauliflower, cabbage, cabbage) by different cooking methods, and found that after boiling in water for 31 minutes, the anticancer components of these vegetables lost at least 51%. It is suggested that the cooking method of "water boiling" should not be used for more than 5 minutes, which is not a burden to health. 3. stew: one advantage of stew soup is that many nutrients will enter the soup, and at the same time, the nutrients will be decomposed and easily digested. But over time, it will destroy antioxidants, vitamin B group and vitamin C. Therefore, it is best to choose slow stew soup. 4. Stir-fry: This is the most commonly used cooking method in China. It is different from frying, using less oil and the temperature is not so high. Many people are used to waiting until the pot is "hot enough" before putting food into the pot. The so-called "hot enough" is that the oil in the pot smokes, which exceeds the smoking point. At this time, the oil has reached a high temperature, which is easy to crack, and the greasy oil is easy to stick to the range hood or kitchen wall. After breathing, it will enter the respiratory tract, which may increase the risk of cancer in the respiratory tract for a long time. If we can control the oil consumption, stir-fry the food more and make the heating surface of the food uniform, we can avoid producing too much oil smoke. Or change the cooking order of "oil, vegetables and water" to "water, vegetables and oil" to minimize the damage of oil smoke! 5. Microwave heating: The temperature generated by microwave heating is extremely high. If the heating time is long, it will destroy the nutrients in food, especially the food with high oil content, and also produce a lot of free radicals, so long-term heating should be avoided. Microwave is a kind of radiation, so many people naturally think it will cause cancer. Microwave electromagnetic waves are essentially the same as radio waves, infrared rays and visible light used in radios and telegrams. The only difference is the frequency. The safety of microwave is the same as that of sunlight-whether it hurts human body depends on the strength of energy and how much energy the microwave reaches human body, so try to stay away from it when using microwave oven. Another safety concern when using microwave ovens is that heating plastic containers will release harmful substances. The FDA (Food and Drug Administration of the Ministry of Health and Welfare) has measured the amount of harmful substances that may be released from various plastic containers during normal microwave heating, and it is required to be less than 1% or even 1% of the harmful dose determined by animal experiments before it can be marked as "microwave-heatable". Therefore, the "microwave-heatable" plastic containers that have passed the FDA inspection are quite safe. If you are still worried, it is safer to use white ceramics or glass containers for microwave. 6. Barbecue: When meat is barbecued in the oven, the fragrance is quite attractive, but with the fragrance, the vitamins and amino acids in the meat are also destroyed, and the protein changes qualitatively, which will affect the intake of vitamins, protein and amino acids in severe cases. What's more, the nucleic acid in meat will produce gene mutation when it is decomposed with most amino acids in Maillard reaction, which may lead to cancer. Because barbecue uses fire and produces smoke, free radicals and carcinogens produced by high temperature will stick to the barbecue meat and then enter the human body. In addition, in the barbecue environment, some carcinogens will enter the human body through the skin, respiratory tract, digestive tract and other ways, and then induce cancer lesions. 7. frying: fried food tastes good and fragrant, so it is widely loved by Asians. However, the frying temperature is usually too high, which will destroy the antioxidants in food and reduce the vitamin content. For example, there are more B vitamins in meat, which will be reduced by 31%~41% when frying. In addition, this method will also increase free radicals and even carcinogens. When the edible oil is reused, the situation is more obvious, and the oil is more prone to rancidity. Call on everyone not to use cooking oil to cook food! Researchers have also found from animal experiments that frying oil heated for more than 21 hours will produce hepatotoxicity. The oil consumption at home can be mastered by ourselves, but the opportunities for modern people to eat out are increasing. Facing snack vendors and catering businesses, it is difficult to ask for a complete ban on the reuse of cooking oil. Based on cost considerations, it is also difficult for snack vendors and catering businesses not to use cooking oil. So pay special attention when eating out. (1) The frying oil is dark in color and thick and turbid in texture. (2) When heated, bubbles are generated, which are difficult to disappear. (3) More oil smoke is produced, and the smoke point is reduced, indicating that the oil has deteriorated. (4) Starch foods such as French fries and fried dough sticks appear dark brown instead of golden yellow. (5) Fried oil has obvious oil consumption odor. (6) The surface of the fried object looks very oily, and the oil can't be dispersed when attached to it. In any of the above cases, it means that the oil quality has deteriorated to the point where it can no longer be used, and it is time to replace it with new oil. Restaurants can buy oil test paper to test edible oil. When the acid value exceeds 2.1, it is time to change oil. Wang Mingyong fan group, Wang Mingyong blog