NSC 170C1 1st Edition Lecture 23 Outline of Last Lecture I Underweight and Disordered Eating Outline of Current Lecture I II III What is Cancer Causes Prevention Current Lecture I What is Cancer why does it occur A Cancer is a group of diseases characterized by the uncontrolled growth and spread of abnormal cells B Begins when a small number of abnormal cells multiply to form a tumor C Cells can break off from the tumor and spread to other parts of the body D There are more than 100 different types of cancer i Prostate cancer is the most common type among American men ii Breast cancer is the most prevalent type among American women iii Lung cancer is the most prevalent cancer throughout the adult population E Decline in the U S Death Rate for All Cancers II Most Cancers start with alterations in DNA A DNA damage mutation can be caused by harmful changes inside the body such as a hormone imbalance or the presence of a virus B 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 carcinogens i Tobacco ii Industrial chemicals iii Ultraviolet UV radiation from the sun iv Radiation from other sources v Cancer causing agents in food and beverages Most Cancers Start with Alterations in DNA D Overweight and obesity are thought to increase risk of many types of cancer and contribute to 14 to 20 percent of all cancer related deaths i Physical inactivity and poor nutrition contribute to overweight and are therefore linked to increased cancer risk III Cancer develops in stages A Initiation Stage i Cell is exposed to an agent that damages the DNA which controls cell growth and division B Promotion Stage i If the damage is not repaired an altered cell can reproduce itself rapidly C Progression Stage i Damaged cells reproduce uncontrollably forming a tumor that invades surrounding tissues ii Cells often break off and travel to other sites in the body This is called metastasis IV Engage in lifestyle Habits That Reduce Your Risk for Cancer A A diet rich in phytochemicals found in colorful vegetables and fruits can help reduce risk of cancer i Antioxidant vitamins and minerals carotenoids vitamins C and E selenium help squelch free radicals that can damage DNA B Retinoids vitamin D folate and selenium can help repair DNA in the initiation stage and stop development of cancer C Omega 3 fatty acids may help reduce cancer cell growth D Fiber helps dilute waste products which may contain cancer promoting agents in your intestinal tract and quickly move these out of the body E Routine physical activity reduces risk of several types of cancer by helping you maintain a healthful weight F Phytochemicals powerful ammunition for your health i 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 phytochemicals iii Phytochemicals benefit health by a Imitating the actions of natural hormones b Protecting cells against chemical reactions that lead to cancer c Preventing formation of carcinogens and blocking their action V Avoid Lifestyle Habits That May Increase Your Risk for Cancer A A diet high in red meats and meats processed by smoking curing salting and or with the addition of chemical preservatives may increase cancer risk i Nitrites give cured meat its pink color can react with amino acids in the meat or your stomach to form cancer causing nitrosamines or nitroamides ii Alcohol can increase risk of cancer of the mouth pharynx larynx and esophagus breast cancer in women and colorectal cancer in men a Enhances the damaging effects of carcinogens in tobacco iii High salt consumption can damage the lining of the stomach and pave the way for stomach cancer