Describe how cancer develops. Explain what carcinogens are, and cite some dietary examples

Question

What will be an ideal response?

Answer 1

The development of cancer, called carcinogenesis, begins as a single cell that loses control of its normal growth and replication processes. A cancer arises from mutations in the genes that control cell division in a single cell. These mutations may promote cellular replication, interfere with growth restraint, or prevent cellular death. The affected cell thereby loses its built-in capacity for halting cell division, and it produces daughter cells with the same genetic defects. As the abnormal mass of cells, called a tumor, grows, a network of blood vessels develops to supply the tumor with the nutrients it needs to support its growth. The tumor can disrupt the functioning of the normal tissue around it, and some tumor cells may metastasize to other regions of the body. In leukemia (cancer affecting the white blood cells) the cells do not form a tumor, but rather accumulate in blood and other tissues.

The reasons cancers develop are numerous and varied. Vulnerability to cancer is sometimes inherited, such as when a person is born with a genetic defect that alters DNA structure, function, or repair. A few cancers are linked with microbial infections. Certain metabolic processes may initiate carcinogenesis, as when phagocytes of the immune system produce oxidants that cause DNA damage or when chronic inflammation enhances the rate of cell division and the risk of a damaging mutation. More often, cancers are caused by interactions between a person’s genes and the environment. Exposure to cancer-causing substances, or carcinogens, may either induce genetic mutations that lead to cancer or promote proliferation of cancerous cells.

Some dietary factors may initiate cancer development. Examples include:

Excessive alcohol, which is associated with cancers of the mouth, throat, breast, and colon.

Meats cooked at high temperatures, such as frying, broiling, and grilling. The high temperatures cause amino acids and creatine in the meats to react together and form carcinogens. Grilling meat, fish, poultry, or other foods over a direct flame cause fat and added oils to splash on the fire, creating carcinogens that vaporize onto the food. Eating grilled food introduces these carcinogens to the digestive system, where they may damage the stomach and intestinal linings.

Diets high in red meat and processed meat (meat preserved by smoking, curing, or salting, or by adding preservatives) can lead to colon cancer.

Fried foods, such as potato chips and French fries, which are associated with acrylamide, a potential carcinogen that is produced when certain starches, like potatoes, are fried or baked at high temperatures.

Also, obesity is a clear risk factor for certain cancers, such as colon, breast in postmenopausal women, endometrial, pancreas, kidney, esophageal and perhaps others, such as gallbladder.