Some Specific Carcinogens In Food

2. Some Specific Carcinogens In Food

2.1 Coal-Tar Dyes

Coal, when heated in the absence of air, is converted to coke (impure carbon), coal gas, and coal tar. The coal tar, a viscous black liquid, is a mixture of many organic compounds. In the 1800s, English arid German chemists learned that they could produce intensely-colored substances when they purified some of these compounds and reacted them with other chemicals. These synthetic substances are known as coal-tar dyes and are used in great quantity by the food, fabric and cosmetic industries.

Americans are consuming coal-tar dyes in their food at an increasingly rapid rate. In 1970, slightly over 3,735,000 pounds were certified by government inspectors. These dyes are used in beverages, candy, ice cream, dessert powder, baked goods and sausages. Levels used ranged from approximately ten parts to five hundred parts per million, the lower levels being used in liquid foods (beverages, gelatin
desserts) and the higher levels in solid foods (pet food, breakfast cereal, etc.).

People have been concerned about the possible toxicity of coal-tar dyes ever since they were introduced in the second half of the nineteenth century.

In view of the repeated dangers associated with coal-tar dyes, one might assume that the dyes now in use have been thoroughly tested. That is not the case. Adequate lifetime feeding studies (two rodent species, forty or more animals per dosage level), which must be done to reveal carcinogenic and cumulative effects, have been conducted for only five dyes (Yellow 6, Red 4, Green 3, Orange B, and Citrus Red 2). Lifetime studies on dogs have been performed only with Orange B, Red 2, Red 4, and Yellow 6. Not one of the coal-tar dyes used in food has been adequately studied for causation of mutations.

If these tests were to be correctly conducted, there is no doubt that they would find that all coal-tar dyes are indeed carcinogenic. They are all extremely poisonous substances and everyone should exclude these products from their diet if they wish to maintain health.

The safety of Violet 1 was a question mark for many years. The dye was used to stamp the Department of Agriculture’s inspection symbol on meat and also to color candy, beverages and pet food. The FDA certified almost 67,000 pounds of this dye in 1972. Consumers may ingest a small amount of the dye when they eat a steak or roast. Workers in packinghouses may be exposed to much greater amounts. The men who imprint USDA’s mark on carcasses frequently get the dye on their hands; occasionally large amounts drip down their hands and arms. One Department of Agriculture meat inspector in North Carolina observed that “the dye is pretty hard to get off. Once you get it on your skin, you almost have to wear it off.”

A study published in 1962 by Dr. W. A. Mannell and his colleagues at Canada’s Department of National Health and Welfare, involved rats. This study indicated that the dye (Violet 1) caused cancer. Of thirty rats fed 3 percent dye in their food for seventy-five weeks, five developed malignant tumors. Three of the tumors were skin tumors. Four of the five tumors occurred in females. Only one out of thirty untreated rats developed a tumor.

In early 1971, nine years after Violet 1 was first suspected of being carcinogenic, the FDA asked the National Academy of Sciences to convene a group of nongovernment scientists to evaluate all available studies. The committee met in Washington on September 1, 1971, and filed its final report in November. The committee’s conclusion and recommendations were finally made public in March 1972, more than a year after the committee was first announced.

The NAS committee dismissed out of hand the Canadian study that indicated that Violet 1 caused cancer. The committee declared the dye safe, but did recommend that a lifetime feeding study be conducted on dogs. The net effect of their report will be to postpone the permanent acceptance or banning of this coloring for at least eight years or more.

Citrus Red 2 is another coal-tar dye under investigation. Florida orange growers use the dye, mainly from October through December, to cover up the mottled green color on oranges, tangelos, and temple oranges.

Four lines of evidence suggest that the dye might be a carcinogen:

  1. When the dye was mixed with cholesterol and implanted in the urinary Bladders of mice, 14.5% of the animals developed tumors; cholesterol without dye caused tumors in 4.5% of the mice.
  2. When the dye was injected under the skin of mice, malignant tumors developed in the lungs.
  3. The liver converts the dye to less noxious substances, which then pass into the urine; one of the intermediates in the conversion process is  1-amino-2-naphthol; there is evidence that this chemical causes cancer.
  4. The walls of the urinary bladders were markedly thickened in animals whose diet contained the dye.

On the basis of this array of evidence the FAO/WHO Committee issued the following warning at its annual meeting:

Citrus Red 2 has been shown to have carcinogenic activity and the toxicological data available were inadequate to allow the determination of a safe limit. The Committee therefore recommends that it should not be used as a food color.

American consumers are endangered if they eat or suck the peel of treated oranges or use the peel in marmalade. Unfortunately, oranges are no longer individually stamped “color added” so it is difficult to identify treated oranges. When oranges are not stamped, supermarkets are supposed to post signs saying “artificially-colored oranges.” FDA administrators in Washington admit that grocers from one end of the country to the other are ignoring FDA’s regulations, but plead that they have too little manpower to stop this “minor” infraction. Workers who produce Citrus Red 2 and who dye the oranges may ingest or inhale relatively large amounts of the chemical. They would be exposed to a proportionately-greater hazard than the average consumer.

The identification of coal-tar dyes on food labels is as inadequate as the testing the chemicals have undergone. The presence of coloring in butter, cheese, and ice cream need not be specified at all. In other foods, colorings are never identified specifically as Violet 1, Green 2, etc., but only say “artificial coloring.”

Name of Dye Effects on Test Animals Permitted In
Amaranth (U.S. Red Dye No. 2) Tumor production jams and jellies, fruit drinks, bread, ice cream, flavored milk, pickles, ketchup
Brilliant Blue FCF Tumor production as above
Citrus Red, No. 2 Tumor production orange skins
Carbon Black Tumor production jams and jellies, fruit drinks, dried eggs

2.2 Tannins and Tannic Acid

Tannic acid occurs in the bark and fruit of many plants notably in the bark of the oak species, in sumac, cherry wild bark, and in coffee and tea. It is used to clarify beer and wine and as a refining agent  for rendering fats. Tannins are used as a flavoring in butter, caramel, fruit brandy, maple and nut flavorings for beverages, ice creams, ices, candy, baked goods and liquors. They art used medically as a mild astringent. When applied, they may turn the skin brown. Tannic acid has a low toxicity when taken orally, but large doses may result in gastric distress. During World War II, liver damage was observed in humans treated with tannic acids for burns. Subsequently, experiments with rats showed repeated subcutaneous injections of a water solution of tannin led to liver toxicity, cirrhosis and tumors.

2.3 Nitrate

Potassium nitrate, also known as saltpeter and nitre, is used in gunpowder and fireworks and as a color fixative in cured meats. Sodium nitrate, also called Chile saltpeter, is used as a color fixative in cured meats. Both nitrates are used in matches and improve the burning properties of tobacco. They combine with natural stomach saliva and food substances (secondary amines) to create nitrosamines, powerful cancer-causing agents. Nitrosamines have also been found in fish treated with nitrates. Nitrates have caused deaths from methemoglobinemia (it cuts off oxygen from the brain). Because nitrates are difficult to control in processing, they are being used less often. However, they are still employed in long-curing processes, such as country hams, as well as dried, cured, and fermented sausages.

2.4 Nitrite

Potassium nitrite is used as a color fixative in the $125 billion a year cured meats business. It is used as a color fixative in cured meats, bacon, bologna, frankfurters, deviled ham, meat spread, potted meats, spiced ham, Vienna sausages, smoked-cured tuna fish products, and in smoked-cured shad and salmon. Nitrite combines with natural stomach and food chemicals (secondary amines) to create nitrosamines, a powerful cancer-causing agent!

2.5 Fish Tumors

Populations of catfish, croakers, calamanders, and other marine animals found in polluted areas often have tumors, while the same species living in a clean environment do not. Scientists have already proven that pollution may be passed along the food chain to people when aquatic organisms accumulate cancer-causing chemicals. Mollusks living in areas polluted with domestic sewage can be reservoirs for disease, and eating mollusks from such areas may result in thyroid disorders and hepatitis.

Pollution certainly seems to play a part in fish tumors. Fish caught in the Fox River on the outskirts of Chicago have almost 16 times as much cancer as do fish caught in Lake of the Woods, Ontario, Canada.

2.6 Ethyl Alcohol

Ethyl alcohol contains ethanol, grain alcohol, and neutral spirits. It is used as a solvent in beverages, ices, ice cream, candy, baked goods, liquors, and gelatin desserts. It was approved in 1976 for use in pizza crusts to extend handling and storage life. It causes cancer when inserted in the rectum of mice in doses of 548 milligrams per kilogram of body weight, and it causes tumors when given orally to mice in 2,770 milligram doses per kilogram of body weight.

2.7 Aflatoxins

Aflatoxins are the best-studied members of a class of compounds called “mycotoxins” (toxins formed by molds). An outbreak in 1960 in England of “Turkey X disease,” an acute liver condition, was traced to peanut meal contaminated with the mold, which occurred after improper harvesting and storage.

A single dose of 5 milligrams per kilogram of body weight has induced tumors in rats. The marked differences in, geographical distribution of liver cancer in humans has long suggested the presence of some common factor. In areas of Africa where there is a high incidence of liver cancer, aflatoxin contamination is common. Aflatoxin B1 is one of the most potent cancer-causing agents known in animal testing. Levels as low as one part per billion 1 produced1 liver cancer in rats. Previous experiments showed a 100% incidence in rats on a lifetime diet containing 15 times that amount of aflatoxin B1.

In addition to liver cancer, aflatoxins have been implicated in the formation of tumors of the stomach, kidney, and some other tissues.

Make sure that the nuts you eat are fresh. Dr. William Wardell, director of the Center for the Study of Drug Development, University of Rochester School of Medicine, speaking at a symposium on Public Issues and Private Medicine, December 6, 1978, in Philadelphia, pointed out that “when a batch of peanuts is imported containing aflatoxin levels that are too high for us to eat, the current method of control is to dilute the contaminated batch with a clean batch to bring the level down to acceptable proportions.”

2.8 Charcoal Broiling

Cancer-causing agents can be formed in charcoal-broiled food according to the NCI. It is safer to boil or poach food than to charcoal broil it. It is believed that at least two kinds of substances are formed in broiling; one is related to the tar in cigarette-smoke condensate and is produced when the surface of the food is charred; the other factor involves the breakdown of some amino acids in protein.

2.9 Carrageenan

An Irish moss derivative, carrageenan absorbs water easily, has a seaweed-like odor and a gluey, salty taste. It is used as a stabilizer and emulsifier in chocolate products, chocolate-flavored drinks, chocolate milk, gassed cream (pressure-dispensed whipped), syrup for frozen products, confections, evaporated milk, cheese spreads, cheese foods, ice cream, frozen custard, sherbets, ices, French dressing, artificially-sweetened jellies and jams.

Carrageenan results in the stimulation of the formation of fibrous tissue when subcutaneously injected
into guinea pigs. When a single dose of it dissolved in saline was injected into the subcutaneous tissues of rats, it resulted in sarcomas after approximately two years. Its cancer-causing qualities may be that of a foreign body irritant, because upon administration to rats and mice at high levels in their diet it did not appear to induce tumors, although survival of the animals for this period was not good. Its use as a food additive and as a treatment for gastric ulcers is being further tested.

2.10 Azo Dyes

A large category of colorings used in both food and cosmetics, azo dyes are characterized by the way they combine with nitrogen. They are made from diazonium compounds and phenol and usually contain a mild acid such as citric or tartaric acid. Among the foods in which they are used are “penny” candies, caramels and chews,  Life Savers, fruit drops, filled chocolates (but not pure chocolates); soft drinks, fruit drinks and ades; jellies, jams, marmalades; stewed-fruit sauces; fruit gelatins; fruit yogurts; ice cream; pie fillings, puddings (vanilla, butterscotch, and chocolate puddings), caramel custard, whips, dessert sauces (such as vanilla and cream in powdered form); bakery goods (except plain rolls); crackers, cheese puffs, chips; cake and cookie mixes, waffle/pancake mixes; macaroni and spaghetti (certain brands); mayonnaise, salad dressings, catsup (Vermin brands); mustard, ready-made salads with dressings; remoulade, bearnaise and holladaise sauces, as well as sauces such as curry, fish, onion, tomato, and white cream; mashed rutabagas, purees; packaged soups, and some canned soups; canned anchovies, herring, sardines, fish balls, caviar and cleaned shell fish.

As far back as 1906 an azo dye, scarlet red, was found to cause tumors in rabbits in Germany. In 1924 it was reported to cause liver tumors in mice. In 1934 Tomizu Yoshida, professor of pathology at Tokyo University, Japan, reported liver cancer in rats that ingested azo compounds in their diet. Azo dyes have since been found carcinogenic in a wide variety of experiments worldwide, but they are still used in our food and cosmetics.

2.11 Sugar

Dr. Hieper has said: “In themselves, sugars may not be carcinogenic—but carcinogenic impurities may be introduced into sugars when concentrated. Sugar solutions are filtered for decolorizing purposes through improperly prepared charcoal containing polycyclic hydrocarbons. Chemicals of the dibenzanthracene type are eluted (washed out) from charcoal by concentrated sugar solutions. Traces may be introduced in this manner and may remain in apparently chemically pure sugars.”

2.12 Saccharin

“Saccharin is a noxious drug, and even in comparatively small doses it is harmful to the human system,” wrote Dr. Wiley in 1913. He tried to keep this nonnutritive adulterant out of food and drink.

As early as 1951, three FDA scientists reported that saccharin at certain levels showed a high incidence of unusual combinations of cancers. The FDA chose to ignore the report. In November 1969 Dr. George T. Bryan, a tumor expert and cancer researcher at the medical school of the University of Wisconsin, reported to the FDA that using saccharin, he had produced bladder cancer in 47% of the mice in one group, and in 52% of another group. In a press interview, Dr. Bryan admitted that although direct cancer hazard to man from saccharin has not yet been established, he was “very suspicious.” He added, “It may take many years before it is known exactly how dangerous the substance is …”

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