Carcinogens in Foods

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Can the very food that sustains us cause cancer? Many would disagree but the fact is that carcinogens (substances that cause a normal cell to change into a cancerous cell) creep in unnoticed into one's daily food in many different ways. They could be present in the form of insecticides that fruit and vegetables have been sprayed with; they could be in the form of growth hormones with which cows and pigs have been fattened in commercial farms; they could be in the preservatives and coloring agents added to food or they could occur naturally in the food itself.


[edit] Why should I be aware of this?

Though there is no definitive study which establishes a direct link between diet and cancer, certain tests have found approximately 20 percent of all known pesticides to be carcinogens. As a result a large number of foods that people consume daily such as vegetables, fish, dairy products, rice, meat, coffee, fruit, and sugar pose a viable threat.

Scientists have gathered much of their information through studies on animals. Tests are also selective as there are too many substances to test. It isn’t always possible for us also to know what extent exposure will pose a risk. Moreover people are simultaneously exposed to numerous substances in the course of their encounters at work, school, or home; in the food they eat; and the air they breathe. It is, therefore, very difficult to single out a particular exposure as having created the risk.

For public health purposes it is, therefore, essential to be informed about carcinogens in food and what extent of lowering of exposure will reduce the risk for us.

[edit] All about carcinogens in foods

[edit] Carcinogens formed during food preparation

Reports from the U. S. Food Standards Agency have found that frying or overheating carbohydrate foods, such as french fries and potato chips generate the known animal carcinogen acrylamide. Their effects and potential risk on human health is being studied.

Barbecuing meat on an open fire creates polycyclic hydrocarbons, such as benzopyrenes, which are also one of the main constituents in cigarette smoke that cause lung cancer. As a result increased intake of fried and broiled food can increase the risk of breast, distal colon, prostate and pancreas cancers. So far more than 20 such chemicals have been identified. Though they are present in small amounts, their long-term effect can be harmful.

Frying starchy foods causes the production of Acrylamides.

[edit] Naturally occurring carcinogens

Though research has been more focused on pesticide residues in food there are numerous naturally occurring carcinogens in food plants. For example, tannins occur widely in plant foods and we ingest them daily in tea, coffee, and cocoa. Experiments on animals have shown that tannic acid causes liver tumors in animals, and may be linked to esophageal cancer in humans.

  • Cycad plants, an important food sources in tropical regions, contain cycasin and related azoxyglycosides which when tested on rats have shown to cause liver and kidney tumors.
  • Safrole, which is a liver carcinogen in rats, is found in sassafras tea, cinnamin, cocoa (trace), nutmeg, and other herbs and spices.
  • Tests on mice have proved black pepper to be carcinogenic

Preservatives and coloring agents All coloring and preservatives added to food are not good for us. Artificial sweeteners (like saccharine & cyclamates) and preservatives which produce nitrosamines are known to cause bladder and stomach cancers respectively.

[edit] Preservatives and coloring agents

All coloring and preservatives added to food are not good for us. Artificial sweeteners (like saccharine & cyclamates) and preservatives which produce nitrosamines are known to cause bladder and stomach cancers respectively.

[edit] Carcinogens and health

Children have more risk of exposure to carcinogens in food as they consume more foods, drink more liquids, and take in more air than do adults. According to leading pediatricians, half of a lifetime's consumption of carcinogens from food is eaten by age five. This is compounded by the fact that children’s rapidly developing organ systems, especially the central nervous system and the brain, are highly susceptible to chemical interference as they are also less able to metabolize and excrete most toxic substances.

[edit] Research findings

The populations of countries where the diet includes substantial amounts of smoked foods and meats treated with nitrates and nitrites, used as preservatives, have higher rates of cancer of the stomach and esophagus. Foods in the American diet that are prepared in these ways include hot dogs, bacon, and ham. To be safe, look for brands of uncured, nitrate-free meat products, such as bacon in natural-food stores.

Scientists have recognized that some chemical constituents of food --either initially present in the food, formed during preparation (especially cooking), or added for preservation -- are capable of inducing tumors in high-dose rodent tests.

Early studies on carcinogens in food concentrated on chemical additives – for example, certain food colors, such as butter yellow (N,N-dimethyl-4-amino-azobenzene), which resulted in the formation of liver and gastrointestinal cancers in rodents. Later, scientists discovered that naturally occurring chemicals in some foods could also be carcinogenic. For example, aflatoxins (chemicals produced by fungi that often contaminate grains and nuts) and plant alkaloids, could also cause cancer in experimental animals. In a review in 1981, researchers concluded that 10% to 70% of human cancer mortality in the U.S. is attributable to the diet, with the most likely figure being about 35%.

However, researching the relationship between food and cancer is not easy. Food contains hundreds of thousands of natural compounds, of which a tiny fraction has been adequately tested for their ability to cause or prevent cancer. Also, cancer studies on laboratory animals are very expensive and yet they do not necessarily tell us if the compound will cause cancer in humans. Nor are they able to state if the food compound will cause cancer at the doses found in the diet, or when mixed with all the other compounds in the human diet. As a result, there is no conclusive evidence yet, that is based on long term human studies, that demonstrates the actual link between diet and cancer.

[edit] Carcinogens and the environment

The US Environmental Protection Agency considers many food packaging materials to be carcinogic. Studies show that a chemical -- perfluorooctanoic acid, or PFOA -- is present in 98 percent of Americans' blood and 100 percent of newborns. It doesn't break down and thus accumulates in the system over time.

[edit] What can I do?

Avoiding carcinogens in food is impossible, since we do not know yet exactly what the relationship between food and incidence of cancer really is.

It is recommended that people eat a varied diet high in fresh fruits and vegetable and avoid excess consumption of foods high in nitrites. While it is not possible to completely eliminate one's exposure to carcinogens, it is possible to avoid the concomitant risk factors that may lead to cancer. Avoiding smoking, eating a varied, balanced diet that includes fiber, and limiting alcohol consumption are all associated with a lowered cancer risk.

[edit] Tips for avoiding potential carcinogens in foods

  • Look for brands of uncured, nitrate-free meat products, such as bacon in natural-food stores.
  • Avoid all cakes, biscuits and cookies that list saturated fats in their ingredients.
  • Wash all vegetables and fruits before consumption in clean water, or with special washing liquids available for the purpose.
  • Eating organically grown vegetables and fruits would limit one’s exposure to pesticides.

[edit] Eating more cancer-fighting fruits and vegetables

There is no doubt that fruits and vegetables are the most important protective factors of diet. They are full of antioxidants, such as vitamin C, vitamin E, carotenoids, flavonoids, selenium, plant phenols and so on. The anti-cancer effect of lycopene found in tomatoes is 2 times stronger than carotene (full in carrots, tomatoes, citrus fruits and other foods). Lycopene has significant effect against prostate, lung and stomach cancers. It is also effective against does prevention and treatment of the pancreas, colon, breast and uterine cancer.

Vitamin C can prevent the synthesis of nitrite, which can be converted into powerful carcinogen nitrosamine. Dietary fiber can promote defecation, then reduce the absorption of carcinogens. Sulfur compounds and carotenoids can inhibit DNA and protein synthesis, and promote normal cell differentiation. Retinol can also increase the body immunity against cancers. Vitamin E may also regulate apoptosis.

Grapes contain trans-resveratrol which help destroy cancer cells and prevent spread of the disease. Carotene exists in carrots, can reduce the incidence of lung cancer. Lentinan exists in lentinan mushrooms, has been proven a effective cancer inhibitor.

Since different fruits and vegetables contain different anti-cancer substances, the right way is to eat a variety of fruits and vegetables, rather than look for a certain kind of anti-cancer vegetables.

[edit] The worst five foods to look out for

Here are the five foods that dietitians agree contain the maximum toxins. Unfortunately, these are all foods that are very commonly consumed, especially by children.

Hot dogs: These usually contain sausages processed with sodium nitrate, mayonnaise loaded with saturated fats, and bread made from refined flour. The Cancer Prevention Coalition recommends that children should not eat more than 12 hot dogs per month because of the risk of cancer. If you can not do without eating hot dogs, make them at home with sausages that do not have sodium nitrite listed among the ingredients.

Processed meats and bacon: These invariably contain sodium nitrite. Bacon is also high in saturated fat, which contributes to the risk of cancers, including breast cancer. If you must have them, try sourcing them from health food stores and making sure that the labels do not list any nitrates in their ingredients.

Doughnuts: The average American’s favourite breakfast food is probably the worst. They contain hydrogenated oils, white flour, sugar, and acrylamides. Reader's Digest calls doughnuts "disastrous" as a breakfast food, and experts agree they are one of the worst cancer foods you can possibly eat.

French fries: Sliced potatoes fried at high temperatures in hydrogenated oil are addictive, no doubt. But not only do they clog your arteries with saturated fat and trans fats, they also contain acrylamides. For added flavour, many chips contain mono sodium glutamate, a chemical not suitable for children. No wonder dieticians say french fries are the worst foods possible to give to children.

Crackers and cookies: Loaded with white flour, refined sugar and trans fats, cookies and biscuits are often considered to be an easy option for children’s snacks. However, the high percentage of trans fats and the presence of acrylamide (formed when these floury products are baked at high temperatures) makes them an unhealthy eating choice.

[edit] Unlearn

[edit] List of known carcinogens in food

Here is a list of some carcinogens in food.

  • Acrylamides are compounds that are created when starchy foods are subjected to high heat. The best example of a process in which these are formed is frying potatoes. Tests on rats in Sweden showed that when deep fried potato and starchy foods cooked at high temperatures were fed to the animals, many of them developed cancer. Researchers from Stockholm University and Sweden's National Food Administration found acrylamide was formed when carbohydrate-rich foods such as potatoes, rice or cereals were heated. The study said that an ordinary bag of crisps may contain up to 500 times more of the substance than the top level allowed in drinking water by the WHO. It also showed that the chemical is found in high carbohydrate foods like bread and potato products which are common in many people's diets.

So far there is no proof that the foods would have the same harmful effects on humans. In the mean time, it probably would be best to not give your children that bag of chips or fries.

  • Nitrosamine is a carcinogenic compound created when we digest meats that contain sodium nitrite. Earlier, this chemical was added to meats to preserve them, today, manufacturers use it because it imparts a healthy pinkish hue to the meat. Almost all processed meats, pickles, smoked foods, cheese, beer and tinned fish contain sodium nitrate.
  • Tannins occur widely in plant foods and we ingest them daily in tea, coffee, and cocoa. Tannic acid has caused liver tumors in experimental animals, and may be linked to esophageal cancer in humans.
  • Cycad plants, important food sources in tropical regions, contain cycasin and related azoxyglycosides that were found to cause liver and kidney tumors when fed to rats.
  • Safrole, which is a liver carcinogen in rats, is found in sassafras tea, cinnamon, cocoa (trace), nutmeg, and other herbs and spices. However, these are consumed in trace amounts by most people, which are probably not enough to cause cancer.
  • Black pepper was found to be carcinogenic to experimental mice. Pyperadine and alpha-Methylpyrroline are secondary amines in black pepper which can be transformed to N-nitrosopiperadine, a strong carcinogen.
  • Trans Fats – in order to increase the shelf life of vegetable oils, manufacturers partially hydrogenate them, ie heat the oils in the presence of hydrogen and metal catalysts. Hydrogenation saturates fats by adding more hydrogen atoms, thereby increasing their melting point (which makes them good for baking) and prolonging their shelf life. However, this process also creates trans fats, which are neither necessary, nor good for health. Trans fats promote heart disease by increasing levels of `bad’ cholesterol, interrupt metabolic processes, and cause belly fat that crowd the organs and strain the heart. Latest evidence shows that when consumed in excess, trans fats may cause cancers. According to the FDA, trans fat is found in vegetable shortenings, some margarines, crackers, cookies, snack foods, and other foods made with or fried in partially hydrogenated oils. [1]. The American Heart Association recommends limiting the amount of trans fats you eat to less than 1 percent of your total daily calories.
  • Pesticide residues get on to our plates if the fruit and vegetables we eat have not been properly washed. There is growing consensus in the scientific community that small doses of pesticides and other chemicals can adversely affect people, especially during vulnerable periods of fetal development and childhood when exposures can have long lasting effects. In one study, conducted in 1992 at Hartford Hospital in Connecticut and published in the Archives of Environmental Health, women with breast cancer had 50 to 60 percent higher concentrations of pesticides in their breast tissue than women who did not have breast cancer. These chemicals can increase estrogenic activity and suppress immune function.

[edit] Source

  1. Revealing Trans Fats, FDA Report

[edit] References

  • Healthy Eating Advisor
  • Diet causing cancer
  • What Are Cancer Causing Foods?
  • Avoiding Carcinogens in Food
  • Naturally-occurring Carcinogens in Food
  • Known and Probable Carcinogens