There are three mouths for the word "cancer". How big is the relationship between cancer and diet?
The "Diet, Nutrition, Physical Activity and Cancer: A Global Perspective (Third Edition)" (updated every 10 years) published by the World Cancer Research Foundation pointed out that unhealthy diets increase the risk of many cancers.
Recently, a study published in the international medical journal "Nature Communications" conducted a systematic evaluation of 860 observational studies involved in the report, and analyzed:
food or nutrient intake There are definite associations with 11 types of primary malignant tumors, which provide strong evidence for the relationship between diet and cancer risk.
Which eating habits are the "accomplices" of cancer? " Life Times " (search for "LT0385" in WeChat to follow) combines the latest research and interviews with experts to tell you what kind of diet can prevent cancer.
Interviewed expert
Shi Hanping, Director of Gastrointestinal Surgery, Beijing Shijitan Hospital, Capital Medical University
Feng Changyan, Director of Nutrition Department, Chongqing University Cancer Hospital
Author of this article | Life Times reporter Dong Changxi
"Cancer from the mouth “Into” has a solid scientific basis
Researchers from the International Agency for Research on Cancer of the World Health Organization and Imperial College London, the meta-analysis found:
On the whole, diet and nutrition may account for the global cancer burden 20%~25%.
Among them, about 10%~15% are due to obesity factors caused by high-calorie diet and lack of physical activity; about 5% are due to alcohol, and about 5% are due to specific dietary factors, such as red meat, processed meat.
Pork, beef, etc. are foods that often appear in daily diets. Therefore, the statement that "red meat causes cancer" may cause fear and anxiety in many people.
Shi Hanping said that meat, especially red meat itself, is not carcinogenic. An important prerequisite for this statement is long-term and large-scale consumption.And there are improper cooking methods.
Such as frying, frying, roasting meat will produce some carcinogens and induce cancer. "Food is not evil and beautiful, and if it is too much, it will cause disasters. If you don't eat too much every day, try to avoid frying and roasting, you don't have to worry about carcinogenesis."
Moreover, compared with the European and American countries, the average intake of the Chinese population is The amount of red meat and processed meat is relatively low.
Feng Changyan said that cancer is a disease caused by a non-single factor. In addition to diet, genetics and environmental characteristics (exposure to toxic substances or hormone disorders, etc.) are all important factors.
The intake of milk and dairy products and calcium mentioned in the report is negatively related to the risk of cancer. Feng Changyan believes that the anti-cancer effect of milk and dairy products is mainly due to the calcium in it:
In addition to calcium in dairy products , lactic acid bacteria is also beneficial to prevent colorectal cancer; casein and lactose may increase the bioavailability of calcium.
Five kinds of bad diets are cancer "accomplices"
In fact, the investigation and research on diet and cancer has been one of the hot spots in the epidemiological field in recent years.
In addition to the latest research evidence, Feng Changyan pointed out that five types of unhealthy diets are recognized as carcinogenic "accomplices":
fried and smoked foods
foods that have been repeatedly fried or smoked at high temperatures, especially fried Burnt food will produce a lot of carcinogens.
Starchy foods, such as French fries, are prone to carcinogens such as acrylamide and polycyclic aromatic hydrocarbons when cooked at a high temperature of 120°C.
The content of benzopyrene in grilled fish, roasted meat and sausages grilled on open or charcoal fire is high, which can induce cell mutations and cause cancer.
Repeated high-temperature heating of edible oil will oxidize, crack, and polymerize fatty acids to produce more carcinogens.Including polychlorinated biphenyls , malondialdehyde and so on.
Pickled and processed meats
Many studies at home and abroad have shown that large amounts of cured foods or processed meats, such as salted fish, sausages, bacon , bacon, etc., will increase the risk of gastric cancer.
Researchers believe that nitrite contained in pickled food will become nitrite after entering the human body. This is a strong carcinogen that will increase the stomach, intestines, , pancreas, etc. The chance of digestive organs becoming cancerous.
In addition, some pickled foods are high-salt foods, which may increase the risk of Helicobacter pylori infection and induce gastric cancer.
Processed meat has increased the intake of carcinogens such as heterocyclic amines, polycyclic aromatic hydrocarbons, and N-nitro compounds due to processing methods such as high temperature and high salt.
Hot food, hot drinks
The International Agency for Research on Cancer of the World Health Organization lists hot drinks above 65°C (such as coffee, tea, etc.) as category 2A carcinogens, claiming that they increase the risk of esophageal cancer .
Epidemiological survey suggests that esophageal cancer, gastric cardia cancer , oral cancer in some areas may be related to the habit of eating hot food. Eating a hot diet for a long time can cause repeated damage to the mucous membrane of the digestive tract, which may cause chronic inflammation and promote tumor occurrence.
The study found that the most suitable temperature for human eating is 10℃~40℃, and the highest temperature generally tolerated is 50℃~60℃.
Moldy and spoiled food
Moldy food not only deteriorates the senses of the food, but also produces strong toxins, which can cause food poisoning, disease or carcinogenesis.
aflatoxin is a metabolite of Aspergillus flavus ,It is usually found in moldy nuts, grains and fermented foods. It is a carcinogen that cannot kill at 100°C for 20 hours. It is extremely stable. It is a long-term continuous intake of aflatoxin-containing foods. It is believed to be an important cause of diseases such as liver cancer, gastric cancer, and bowel cancer.
Surveys and studies in Africa, Southeast Asia and other regions or countries have shown that where food is heavily contaminated by aflatoxin, the incidence of liver cancer is very high.
Alcohol
In addition to damage to the liver, more and more evidence shows that alcoholic beverages increase the risk of a variety of cancers.
Among them, ample evidence suggests that alcoholic beverages are one of the causes of oral cancer, laryngeal cancer , esophageal cancer (squamous cell carcinoma), liver cancer, colorectal cancer, and breast cancer.
The relationship between alcohol and a variety of cancer risks may be related to a variety of mechanisms:
Evidence shows that the active metabolites of alcohol (such as acetaldehyde) have carcinogenic effects; alcohol can be used as a dissolution to promote carcinogens to enter cells; heavy drinking It may result in a lack of certain nutrients in the diet, and make the tissue more sensitive to carcinogenic effects.
What kind of diet can prevent cancer?
Regarding cancer prevention, there is currently no specific and exact single food, but there are dietary rules to follow. Shi Hanping suggested that on the basis of maintaining his own eating habits and hobbies, try to do the following 4 points.
There are "choices" in daily diet
Take: consciously increase the intake of protein (eggs, milk, fish, meat, beans) and vegetables; more use of cooking and processing methods such as steaming, boiling and simmering.
House: reduce the intake of red meat and processed meat, try to minimize the use of frying, stir-frying, especially roasting; reduce carbohydrates with high glucose load, such as alcohol, refined sugar, refined rice noodles and their products; avoid or limit Drinking.
Diverse diet and balanced nutrition
Food diversity determines the diversity of intestinal bacteria, which determines the health of the human body; a variety of foods-fruits, vegetables, whole grains, protein and dairy products must be guaranteed every day.
To consciously eat some foods that you don't usually eat or eat less. Pay attention to eat more fruits and vegetables, especially cruciferous vegetables:
such as cabbage, broccoli, cauliflower, kale, cabbage, cabbage, etc. They are rich in vitamins and minerals And some antioxidants, among which sulforaphane can also promote the expression of tumor suppressor genes and reduce the incidence of tumors.
Some vegetables that can be eaten raw are best eaten raw to reduce the damage to vitamins and folic acid caused by heat processing.
It is best not to go to extremes in your diet.
Pure vegetarian food or pure meat eating is not a healthy diet.
Current nutritional recommendations for cancer prevention include increasing the intake of fruits and vegetables, especially foods rich in vitamins and dietary fiber, which may reduce the risk of cancers in the digestive tract and breast cancer.
Meat, especially red meat is rich in iron, protein, zinc, niacin, vitamin B12 , thiamine, riboflavin and phosphorus, etc., which are essential to the human body It is recommended that everyone take in an appropriate amount of nutrients every day.
Reasonably arrange eating time
Nutritional chronology studies have found that eating the same amount or calorie meals at different times has very different nutritional and health effects.
For healthy adults, it is recommended to eat full and well-eaten breakfast and lunch, eat less for dinner, and eat early; the total food intake of each day is 30%, 40%, 30% of the morning, noon, and evening respectively Proportionate distribution; no midnight snack, no snacks, and try to avoid eating 4 hours before going to bed.
Source: Life Times
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