Modern methods of raising animals for food have made matters even worse for meat-eaters. Antibiotics, hormones, heavy metals, dioxins, and various other compounds are raising the risk of cancer.
Because chickens are raised in such crowded and unhealthy conditions, they are very susceptible to disease, so in an attempt to keep them alive through conditions that would otherwise kill them, farmers feed them an array of antibiotics, including one that contains the most toxic form of arsenic. A report from the U.S. Department of Agriculture—published in Environmental Health Perspectives in January 2004—revealed that chicken contains three to four times more potentially poisonous arsenic than other poultry and meats. Eating a typical 2 ounces of chicken a day means ingesting 3.6 to 5.2 micrograms of cancer-causing arsenic.
And arsenic isn't the only thing you need to worry about the next time someone offers you a chicken leg. More than 95 percent of our exposure to dioxin, a well-known carcinogen, comes from eating animal products (the rest is environmental; none comes from vegan foods). Researchers with the Institute of Medicine have even recommended that school cafeterias offer more foods that are low in animal fat so that children aren't exposed to unhealthy levels of dioxins, dangerous byproducts of industrial and natural combustion that can accumulate in body fat. According to Michael Taylor of Resources for the Future, "The most direct way to reduce dietary exposure to dioxins is to reduce consumption of animal fat." Remember, more than half the calories of even the leanest chicken comes from fat.
Fish, in addition to containing concentrated (and carcinogenic) animal protein, is often very high in environmental contaminants. Fish commonly contains mercury, dioxins, polychlorinated biphenyls (PCBs), and other organochlorine pesticides. These contaminants, which have been linked to cancer and other health problems, tend to accumulate in body fat and remain in the body for decades.
In fact, 80 to 90 percent of dietary pesticide exposure, as well as 100 percent of dietary hormone and dioxin exposure, comes from eating animal products, and many of these chemicals are known to cause cancer in human beings.
Finally, additional carcinogens form when meat is cooked. These cancer-causing chemicals, specifically called heterocyclic amines, are found in cooked red and white meats, including fish and poultry. In fact, the amount found in grilled chicken is 15 times higher than in hamburger or steak.
Source : GoVeg