NSC 170C1 1st Edition Lecture 23Outline of Last Lecture I. Underweight and Disordered Eating Outline of Current Lecture I. What is Cancer? II. CausesIII. PreventionCurrent LectureI. What is Cancer, why does it occur? A. Cancer is a group of diseases characterized by the uncontrolled growth and spread of abnormal cellsB. Begins when a small number of abnormal cells multiply to form a tumorC. Cells can break off from the tumor and spread to other parts of the body.D. There are more than 100 different types of canceri. Prostate cancer is the most common type among Americanmenii. Breast cancer is the most prevalent type among American womeniii. Lung cancer is the most prevalent cancer throughout the adult populationE. Decline in the U.S. Death Rate for All CancersII. Most Cancers start with alterations in DNAA. DNA damage (mutation) can be caused by harmful changes inside the body, such as a hormone imbalance or the presence of a virusB. Only 5 to 10 percent of cancers are thought to be related to a specific “cancer gene”C. DNA mutations commonly occur due to long-term exposure to harmful substances called carcinogensi. Tobaccoii. Industrial chemicalsiii. Ultraviolet (UV) radiation from the suniv. Radiation from other sourcesv. Cancer-causing agents in food and beveragesMost Cancers Start with Alterations in DNAD. Overweight and obesity are thought to increase risk of many types of cancerand contribute to 14 to 20 percent of all cancer-related deathsi. Physical inactivity and poor nutrition contribute to overweight and are therefore linked to increased cancerriskIII. Cancer develops in stagesA. Initiation Stagei. Cell is exposed to an agent that damages the DNA which controls cell growth and divisionB. Promotion Stagei. If the damage is not repaired, an altered cell can reproduce itself rapidlyC. Progression Stagei. Damaged cells reproduce uncontrollably, forming a tumor that invades surrounding tissuesii. Cells often break off and travel to other sites in the body. This is called metastasisIV. Engage in lifestyle Habits That Reduce Your Risk for CancerA. A diet rich in phytochemicals, found in colorful vegetables and fruits, can help reduce risk of canceri. Antioxidant vitamins and minerals (carotenoids, vitamins C and E, selenium) help squelch free radicals that can damage DNAB. Retinoids, vitamin D, folate, and selenium can help repair DNA in the initiation stage and stop development of cancerC. Omega-3 fatty acids may help reduce cancer cell growthD. Fiber helps dilute waste products, which may contain cancer-promoting agents, in your intestinal tract and quickly move these out of the bodyE. Routine physical activity reduces risk of several types of cancer by helping you maintain a healthful weightF. Phytochemicals: powerful ammunition for your healthi. Phytochemicals are naturally occurring plant chemicals thought to support health. They are found in fruits, vegetables, beans, and some whole grains.ii. Research does not support claims that taking supplements is as helpful as consuming whole-food sources of phytochemicalsiii. Phytochemicals benefit health by:a) Imitating the actions of natural hormonesb) Protecting cells against chemical reactions that lead to cancerc) Preventing formation of carcinogens and blocking their actionV. Avoid Lifestyle Habits That May Increase Your Risk for CancerA. A diet high in red meats and meats processed by smoking, curing, salting, and/or with the addition of chemical preservatives may increase cancer riski. Nitrites: give cured meat its pink color; can react with amino acids in the meat or your stomach to form cancer-causing nitrosamines or nitroamidesii. Alcohol can increase risk of cancer of the mouth, pharynx, larynx, and esophagus, breast cancer in women, and colorectal cancer in mena) Enhances the damaging effects of carcinogens in tobaccoiii. High salt consumption can damage the lining of the stomach and pave the way for stomach