I. Food additives
1.Nitrosamines
Nitrite is one of the most commonly used food additives, which can inhibit the growth of Clostridium botulinum, while keeping the meat color fresh and tender. It is mainly used in cooked meat foods, such as ham, roast meat, sausages, luncheon meat, salami, salted beef cans, smoked fish, canned fish, etc. Sometimes in cured fish, meat, but also use nitrite as a coloring agent and preservative. Nitrite itself is not carcinogenic, but it combines with amines produced after protein metabolism to form nitrosamines, which are highly carcinogenic. At first, it was found that nitrosamines could cause liver cancer in rats, and later, someone used nitrosamine derivatives and induced esophageal cancer in rats. The high incidence of certain human cancers is often a high intake area of nitrosamines, and Linzhou City, Henan Province, China is known as a high incidence area of esophageal cancer, where residents have the habit of eating sauerkraut. Sauerkraut is a kind of pickle made by mold fermentation, and researchers have found that it contains high nitrosamines. Cigarette smoke contains a lot of nitrosamines, which can easily dissolve in saliva and enter the body. Beer contains small amounts of nitrosamines, which are produced during the heating and drying process of barley, and some of them also come from hops. In addition, nitrosamines are synthesized in the human body, with the main sites being the mouth and stomach. It is therefore recommended that.
(i) eat less cured and smoked meats and other foods rich in nitrosamines or their precursors.
②Cured fish and meat should be exposed to the sun for half an hour before consumption, so that the ultraviolet rays of the sun break down the nitrosamines, or then soaked and rinsed.
③brush teeth regularly to maintain oral hygiene and reduce nitrosamines that may be produced in the mouth due to bacterial activity.
④Vitamin C has the effect of stopping the synthesis of nitrosamines, and at the same time is an antioxidant, non-toxic side effects, and can be supplemented in appropriate amounts according to the situation.
2.Coloring
Commonly used pigments in food and beverages are a variety of pastries, candy, meat products, baked goods, cool drinks, ice cream, sorbet, fruit jelly, fruit juice and fast food. Many food colorings are toxic and many are carcinogenic, with common cancer-causing sites in the liver and breast tissue. There are synthetic and natural pigments. Most synthetic pigments come from coal tar, and natural pigments are not absolutely safe and can cause problems beyond a certain amount. It is wiser to keep exposure to them to a minimum and not to buy or eat foods such as pastries, beverages and wine that are too brightly colored. There is a tendency to use colorings that present the original color of the food more and more commonly, making it difficult to identify them. Be wary of overly colorful, overly fragrant cosmetics, it is best to use less.
3.Sweetener
Saccharin is a mineral, sweetness is equivalent to 500-700 times of sucrose, no nutritional value, quickly excreted with urine after ingestion. However, there are signs that it can cause cancer in humans, and the evidence is getting stronger. Saccharin can cause bladder cancer in experimental animals, and since it can cause cancer in animals, it is not convincing to say that it is absolutely safe for humans, so many countries still advocate banning the use of saccharin. At present, there is no need to worry too much about saccharin food, as long as it is not used in large quantities and long-term.
Food contamination
Food contamination is also an important source of dietary carcinogenesis, mainly including
1.Pesticides
Commercially available fruits and vegetables often contain pesticide residues, which can also enter the food processed by these agricultural products. Many of these pesticide residues are soluble in fat, and rinsing with citric acid or other weaker acids before consumption can get rid of some pesticide residues. However, because many pesticides remain under the skin of fruits and vegetables, peel them deeper to avoid ingesting pesticides. Organochlorine pesticides are known to cause hepatocellular tumors in mice, organophosphorus pesticides in animal model studies have shown to be carcinogenic, many scientists believe that certain pesticides, there is a great danger of carcinogenicity to humans.
2, fungal contamination
Aflatoxin is a strong carcinogen produced by Aspergillus flavus. Carbohydrate food often under high temperature and high humidity conditions, producing aflatoxin. Therefore, nuts, food, seeds should be kept dry when harvesting and storage. Aflatoxin has been shown to cause liver and kidney cancer and, in a few cases, colon cancer in rats and bears in zoos. It is recommended that nuts, corn, grains and seeds that are not completely dry and show signs of mold be avoided, as well as moldy bread. Many kinds of fungi have been isolated from moldy bread, and three were found to cause cancerous tumors in rats.
3.Polycyclic aromatic hydrocarbons
Polycyclic aromatic hydrocarbons are common and widespread contaminants in processed foods, food smoked or fried by smoke and fire, can produce benzo(a)pyrene. The World Health Organization proved that the heating of proteins, fats and carbohydrates, etc. can produce benzo(a)pyrene.
In addition, carcinogens formed during the cooking process may also cause cancer, although not due to pollution. Many people like to eat food with burnt crumbs, but the burnt part often contains carcinogens, which are formed by the caramelization of proteins, fats and sugars. Scientists have reported that roast beef, fish and other foods whose smoked and charred parts contain strong mutagens, and some people have found that there is a stainless steel plate fried beef patties, 200 ° C, that is, the rapid formation of mutagenic substances. Temperature increases, the mutagen content increases exponentially.