Researchers have confirmed from experiments that the ability of dietary fiber to prevent cancer is often influenced by internal and external factors, such as water solubility or insolubility, fermentation or not, storage methods, and food preparation processes. According to the World Health Organization, among the 10 million cancer deaths worldwide, if we can pay attention to our diet early and reduce external cancer-causing factors, we can definitely reduce the chance of getting cancer by 30% to 40%, and if we can limit the harmful effects of smoking, we can reduce it by another 30%. In addition to the general knowledge of reducing exposure to cancer-causing factors and environment, it is also important to pay attention to dietary prevention in daily life, hoping to stop the progression of cancer with the foods or drugs that we eat everyday, which are naturally known as cancer chemoprevention or drug prevention. It has been confirmed from experiments that the ability of dietary fiber to prevent cancer is often changed by internal and external factors, such as water solubility or non-water solubility, fermentation or not, storage methods, food preparation process, etc. Therefore, the dietary fiber in the daily diet should be treated as a natural food. Therefore, it is impossible to predict the actual function of dietary fiber in the daily diet. In addition, the function of high fiber in cancer prevention depends on the cooperation and interaction of various other trace components. For example, natural inclusions in vegetables and fruits can fight cancer: small molecule nutrients have antioxidant effects, beta-carotene, vitamins C and E, rare metals such as selenium, and phytochemicals that are not nutritious in themselves, such as isothiocyanates, flavonoids, primulas, and pine oil, all of which are present in vegetables and fruits and play an important interactive role, and will be an important study for cancer prevention in future clinical trials. Soluble dietary fiber can be fermented by bacteria in the large intestine, and its possible anti-cancer mechanisms include: 1) improve the ecology of intestinal bacteria, so that there is an increase in the amount of foreign bacteria; these bacteria can increase the volume of stool (even accounting for ½ volume); 2) under the action of anaerobic bacteria in the intestine, the production of short-chain fatty acids with the maintenance of normal differentiation of the colonic mucosa, and inhibit cancer generation; 3) regulate the endocrine In addition, the lignin produced by the bacterial decomposition of fiber also has the function of anti-emotional hormone, which may explain why a high fiber diet can prevent gynecological tumors. At present, scholars are still actively exploring: 1. Is the effect of dietary fiber on cancer prevention only from the fiber itself, or does the high-fiber diet rich in carotenoids, cites and other substances provide an additive effect? 2. Is there a difference in the cancer-preventive role of each dietary fiber? Is there a difference between water-soluble and non-water-soluble fibers? Until the answers to these questions are known, the current recommendations of the American Cancer Society emphasize an overall high fiber diet (more vegetables, fruits, legumes, and whole grains) rather than a specific type of dietary fiber. Dietary fiber is a type of non-starchy polysaccharide in carbohydrates, including cellulose, hemicellulose, pectin, and resistant starch. Some people in the nutrition industry call dietary fiber the “seventh major nutrient” in addition to protein, fat, carbohydrates, vitamins, minerals and water. The reason why it is separated from carbohydrates and become an independent nutrient is because it is closely related to people’s health, especially it can be associated with a variety of diseases. There are many factors that contribute to constipation, but it is well known that dietary fiber intake is associated with constipation. Human trials have shown that eating more vegetables and fruits can indeed relieve constipation because dietary fiber stimulates intestinal motility and increases the weight of feces. Dietary fiber can increase the feeling of satiety, can increase the filling of the stomach, delay the emptying of gastric contents, so that the absorption of glucose tends to slow down, and therefore can prevent and control the occurrence of obesity. Dietary fiber-rich foods or dietary fiber supplements can lower blood sugar, which has been confirmed by many studies. Because soluble dietary fiber can form a sticky substance in the stomach, thus affecting the absorption and utilization of glucose, it does not cause a sudden rise in blood sugar after meals. Eating more starchy carbohydrates rich in all fibers is beneficial in the prevention of hyperlipidemia and ischemic heart disease. In particular, the ability of dietary fibers to lower serum cholesterol is a clear scientific understanding today, due to the fact that some fibers reduce the absorption of dietary cholesterol. The epidemiology related to dietary fiber and bowel cancer confirms that the intake of vegetables and fruits is negatively associated with risk factors for the development of bowel cancer. This is because the intake of dietary fiber shortens the duration of fecal retention in the large intestine, diluting carcinogens while adhering to other carcinogens. In addition, bacteria in the intestine can break down dietary fiber to produce short-chain fatty acids, lowering the pH of stool and inhibiting the production of carcinogens. Furthermore, dietary fiber can change the bacterial phase in the colon and increase the antioxidants in the intestinal lumen, all of which can help the body escape from cancer. Recent studies have also found that vegetables contain many phytochemicals, such as anthocyanins, lycopene, lutein and isoflavones, which are very beneficial to human health. Therefore, the Food and Agriculture Organization of the United Nations and the World Health Organization have issued communiqués urging people to eat more vegetables and fruits. China has also made the following requirements for the appropriate intake of dietary fiber: 25g/day for low-energy diets, 30g/day for medium-energy diets, and 35g/day for high-energy diets. Dietary fiber is not only in vegetables What about the high price of vegetables and people eating less? In fact, dietary fiber is not only in vegetables, we can use the dietary fiber in other foods to meet our health needs. The main source of dietary fiber is cereals, especially unprocessed or coarsely processed cereals, with whole grains and wheat bran being the most important. The most abundant food is insoluble dietary fiber, the bran of cereals, whole grains and dried legumes, dried vegetables and nuts are also good sources of insoluble dietary fiber, while soluble fiber is rich in oats, barley, fruits and some legumes. For example, cereals, per 100 grams (the same below), oat noodles contain 12.2 grams of dietary fiber, wheat 11.9 grams, sorghum rice 10.4 grams, millet 9.0 grams, corn flour 8.1 grams. The content of carbohydrates in soy foods is about 20% to 30%, mostly fiber and soluble sugar. The content of other legumes is also high, such as peas 10.4 grams, kidney beans 8.3 grams, mung beans 6.4 grams; the dietary fiber of soybean products should not be underestimated, soy milk 1.1 grams, vegetarian chicken 0.9 grams, mung bean sprouts 0.8 grams, tofu 0.5 grams. Dietary fiber in nuts is also high, such as peanuts with 6.3% dietary fiber content, hazelnuts for 9.6%, almonds for 19.2%; like chestnuts, lotus seeds, gravy, etc. Although rich in starch, but dietary fiber content are also between 1.2% to 3.0%, plus its starch structure and rice, flour is different, its glycemic index is much lower than refined rice and flour. Mushroom and algae food should be one of the vegetables, including edible mushroom and algae food, which are rich in protein, carbohydrates, vitamins and trace elements, and also rich in dietary fiber, such as shiitake mushroom as 31.6 grams, silver fungus 30.4 grams, black fungus 29.9 grams, nori 21.6 grams, mushroom 21.0 grams, and seaweed 6.1 grams. Moreover, these foods have health effects such as improving human immune function, preventing blood clots and anti-tumor. Therefore, when the supply of vegetables is low or eat less, we may want to eat more of the above foods to ensure that the body’s need for dietary fiber. Meat more vegetables less to eat smart grain meat with eat. Animal and poultry meat protein nutritional value is high, it is appropriate to eat with cereal, because the former lysine, the latter lysine less, with the consumption of protein can play a complementary role. In addition, we should pay attention to the meat of livestock and poultry scattered to each meal, do not concentrate on eating, more and vegetables with, so that the amount of vegetables is not too much, economically acceptable, and can avoid eating too much fat and cholesterol at one time. Mixed rice. Southerners love to eat rice, you can mix some barley, oats, sweet potatoes, beans and other foods in the rice, both to improve the nutritional value, but also to increase dietary fiber. Eat more soy products. Beans have a high dietary fiber content, especially bean skin. There are foreign companies that process and grind bean skins into powder and use them as high fiber for baked goods. Moreover, consumption of fiber-containing bean foods can significantly lower serum cholesterol. Also, try sprouting some of your own beans for an economical, seasoned taste. Don’t neglect dried vegetables. As mentioned earlier, dried vegetables are also a good source of dietary fiber, and many of them taste great with meat. Soup and porridge for variety. Guangzhou people love thin food, summer can be hydrated, you can also deliberately choose some fiber-rich food to make a pattern. Such as mung bean porridge, fungus hawthorn porridge, glutinous rice, red dates porridge, seaweed fungus soup, double ear (black and white fungus) soup, nori cucumber soup, etc. Drink more yogurt. The reduced lactose in yogurt makes it easy for lactose intolerant people to accept, and the content of vitamins A, B1 and B2 in it is similar to that of fresh milk. Most importantly, the lactic acid bacteria in yogurt can inhibit the growth of some spoilage bacteria when they enter the intestine, adjusting the intestinal bacteria phase and protecting intestinal health. Eat more fruits. Although fruit can not replace vegetables, but fruit is also alkaline food, can neutralize the animal and poultry meat such as acidic food, and fruit is also an important source of vitamins and minerals. Only dietary fiber in food can prevent cancer How serious are the consequences of not being able to control your mouth? If you don’t say it, you will be shocked. It is well known that meat lovers are prone to colon cancer, but in the opinion of experts, this is just the tip of the iceberg. Recently, Qin Jian, the director of education department of the First Hospital of Sun Yat-sen University, professor of Chinese medicine and doctoral supervisor, talked about in his lecture “Diet and Tumor” that the intake of total calories, fat, protein and carbohydrates are all intrinsically related to tumor, and only dietary fiber has cancer prevention effect. How to prevent diet from causing cancer? Whenever we talk about the causes and prevention of tumors, the key words “over-eating” and “meat-loving” are always inevitable. The most familiar one is that the prevention and treatment of colorectal cancer must start from reducing high-fat diet. However, most people only know one thing but not the other, but it turns out that fat is also closely related to the occurrence of breast cancer. “A high-fat diet leads to high estrogen and high lactogen, which are necessary for the development of breast tumors.” Qin Jian, director of the Education Division, professor of Chinese medicine and doctoral supervisor at the First Hospital of Sun Yat-sen University, said that the love of meat increases the risk of breast cancer, but it is not the only dietary risk factor; if the total calorie intake is too high, the incidence of breast cancer and colorectal cancer and even gallbladder-biliary tract cancer, cervical cancer, ovarian cancer and endometrial tumor will also increase. Studies have shown that an increase in total daily calorie intake from 2700 to 3900 kcal is associated with a more than twofold increase in mortality from colon and rectal cancers. The incidence of breast cancer in women on a high-calorie diet is 1.2 times higher than that in women on a low-calorie diet. However, reducing the body’s nutrient supply may also cause the body to be weakened and its resistance to cancer will still occur. Recommendation: Total calorie intake should not be too much or too little, preferably controlled at 2200-2700 kcal per person per day. Fat intake is generally considered to be 16%-20% of total calories, and vegetable fats (such as vegetable oil, etc.) should be increased. Eat less high cholesterol foods, such as small shrimps, puffed eggs, duck eggs, pig liver, dried shrimp skin, eggs, beef liver, tripe, crabs, cuttlefish, eels, cakes, ice cream, and whole milk. Excessive protein and carbohydrates cause tumors In the reporter’s impression, it is rare to hear that protein and carbohydrates have any association with tumors. But in Professor Qin Jian’s lecture, the reporter got this tip unexpectedly. He pointed out that when the protein content in the diet is too low, it can promote the occurrence of tumor, and when the amount of protein intake is 2 to 3 times of the normal need of human body, it can also enhance the chemical substances to induce tumor. Therefore, it is not appropriate to consume too much or too little protein. And there are some differences in the effects of animal and vegetable proteins on tumors. From the research, animal protein is positively correlated with breast, colon, prostate and pancreatic cancers, while plant protein (such as beans) in turn can significantly inhibit tumor development. There are not many studies on the relationship between carbohydrates and tumors, but some studies have shown that sugar and starch are associated with tumors such as colorectal, colon, rectal and gastric cancers, and pancreatic cancer. Excess carbohydrates can lead to excess total calories, which in turn increases the risk of tumor development. Recommendation: The daily supply of protein should be 70-80g per person, of which soy protein should account for 20%. Carbohydrates should account for 60%-70% of the total calorie composition. Eating more dietary fiber can reduce the incidence of many kinds of tumors Perhaps we may ask: What else can we eat then? In fact, there are factors in diet that promote tumors and also prevent tumors, and dietary fiber is a good medicine. Dietary fiber can significantly reduce the incidence of colorectal, rectal, colon, breast, stomach, esophageal, cervical, pancreatic, oral and pharyngeal cancers. Its cancer prevention mechanism is mainly reflected in: reducing the concentration of carcinogens in the large intestine; shortening the passage time of toxic substances in the intestinal lumen and reducing the contact time between carcinogens and tissues; influencing the production of certain carcinogens or pre-carcinogens; regulating the endocrine system, etc. Take colon cancer as an example, when the amount of consumed dietary fiber is 28% (very high level) and 15% (high level), the incidence of colon cancer is very low, and when the intake of dietary fiber is 5% (low level), the incidence of colon cancer is very high. Suggestion: Eat more vegetables, fruits and whole grains on a daily basis, especially lemons, citrus fruits, cruciferous vegetables and mushrooms. The so-called cruciferous vegetables include broccoli, cabbage, cauliflower, watercress, kale, kohlrabi, mustard, radish, etc. The human body needs nutrients for metabolism, and each nutrient has its own role. Nowadays, people are more aware of health care and generally focus on the intake of protein, fat, carbohydrates, inorganic salts and vitamins in daily life, but often neglect the intake of dietary fiber. Previously, nutritionists viewed fiber as something with no nutritional value, but research in the last decade or so has disproved this “theory”. The American Institute of Cancer Research advocates people to eat more fiber-rich foods, such as wheat bran and rice bran, and believes that these foods are the best cancer prevention food. Domestic nutrition experts also clearly suggest that people should eat different types of dietary fiber foods every day, such as coarse grains, mixed grains, beans, vegetables and fruits. Dietary fiber in nutrition refers to a large group of substances in food that cannot be digested and absorbed in the small intestine. Fiber can be divided into two main categories, namely soluble fiber and insoluble fiber, which are both beneficial to human health. Soluble fiber includes: ① cellulose, mainly in wheat bran, rice bran; ② hemicellulose, present in whole grain foods; ③ lignin, present in fruits, vegetables and grains. Insoluble fibers are plant gum and pectin, which exist in legumes and fruits and vegetables, especially fresh fruits and vegetables. Dietary fiber cannot be absorbed by the body and can form a mucosal gel coagulation in the intestine, which can adsorb harmful and excess substances such as toxins and cholesterol. In addition, fruit fiber balances excess fat intake in the body and can prevent cardiovascular disease and colon cancer. Fiber can prevent constipation while effectively retaining water, so constipated people can eat more foods rich in dietary fiber, such as beans, celery, potatoes, etc. Food fiber can also inhibit the absorption of cholesterol, so people with high blood lipids should also eat more food containing more dietary fiber. Fiber can also reduce the speed of digestion, which is beneficial for diabetics. Foreign studies have reported that fruits and vegetables that contain a lot of fiber can lower the glucose level in the blood and therefore can help control type 2 diabetes, and studies have confirmed that eating 50 grams of fiber per day can lower blood sugar by 10%. At a national academic conference on oncology at the beginning of this century, some experts pointed out that the disease spectrum is gradually changing with the change of lifestyle, diet structure and living environment. How to curb this trend, experts believe that people should keep their fat intake below 30% of total calories and pay attention to dietary fiber intake, which is also beneficial for cancer control. Therefore, don’t forget to set a plate of foods rich in dietary fiber that are good for human health at our hearty dinner table. Foods containing dietary fiber Coarse grains, mixed grains, vegetables and fruits are the main ways to take in dietary fiber, and it is best not to replace them with various substitutes. Foods rich in fiber include cornmeal, buckwheat noodles, sorghum rice, pinto beans, mung beans, potatoes, peanuts, almonds, peas, green beans, garlic, green garlic, leeks, hollow cabbage, amaranth, rape moss, soybean sprouts, mung bean sprouts, bamboo shoots, cabbage, chard, rape, lettuce, cucumber, celery, radish, apples, pears, bananas, pineapples, peaches, citrus, red dates, etc. And animal foods, fats and oils and dairy foods do not contain dietary fiber.