Definition A class of diseases characterized by out-of-control cell growth. There are over 100 different types of cancer, and each is classified by the type of cell that is initially affected. Cancer harms the body when damaged cells divide uncontrollably to form lumps or masses of tissue called tumors . Benign – tumors that stay in one spot and demonstrate limited growth Malignant – tumors that divide, grow and move throughout the body
Risk Factors Three main causes of cancer: Smoking (tobacco) Dietary imbalances (excess fat and calories; inadequate intake of fruits, vegetables, fiber, and calcium) Chronic infections leading to chronic inflammation
Other Risk Factors Growing older Sunlight Ionizing Radiation Certain chemicals Viruses and bacteria Certain hormones Family history of cancer Alcohol Lack of physical activity or being overweight
Obesity and Cancer Statistics In 2001, experts concluded that cancers of the colon, breast (postmenopausal), endometrium (the lining of the uterus), kidney, and esophagus are associated with obesity. Some studies have also reported links between obesity and cancers of the gallbladder, ovaries, and pancreas.
Obesity and Cancer Obesity and physical inactivity may account for 25 to 30 percent of several major cancers—colon, breast (postmenopausal), endometrial, kidney, and cancer of the esophagus. A recent report estimated that, in the United States, 14 percent of deaths from cancer in men and 20 percent of deaths in women were due to overweight and obesity.
Obesity and Cancer Mechanism – high levels of insulin or insulin-related growth factors in obese people may promote tumor development. an increased exposure to sex steroids, estrogen and androgen (renal cell cancer). increases in gastric reflux due to obesity may increase risk (esophageal and stomach cancer). risk has been linked to men with higher levels of leptin, insulin, and IGF–1 (insulin-like growth factor-1) (prostate cancer).
Obesity and Cancer There is some evidence that abdominal obesity may be more important in colon cancer risk. In men, a high BMI tends to be associated with abdominal fat. In women, fat is more likely to be distributed in the hips, thighs, and buttocks. Thus, two measures of abdominal fat, waist-to-hip ratio or waist circumference, may be better predictors of colon cancer risk.
Aging and Cancer Aging is in good part due to the oxidants produced as by-products of normal metabolism. These oxidants cause damage to DNA, proteins, and lipids.
Aging and Obesity The degenerative diseases of aging such as cancer, cardiovascular disease, cataracts, and brain dysfunction, are increasingly found to have an oxidative origin. It is argued that dietary antioxidants, such as Vitamins C and E and carotenoids, play a major role in minimizing this damage and that most of the world's population is receiving inadequate amounts of them, at a great cost to health.
Antioxidants Antioxidants are substances that may protect cells from the damage caused by unstable molecules known as free radicals. Antioxidants neutralize free radicals that are the natural by-product of normal cell processes. Exposure to various environmental factors, including tobacco smoke and radiation can lead to free radical formation.
Antioxidants In humans, the most common form of free radicals is oxygen. When an oxygen molecule becomes electrically charged or “radicalized” it tries to steal electrons from other molecules, causing damage to the DNA and other molecules. Over time, such damage may become irreversible and lead to disease including cancer. Antioxidants are often described as “mopping up” free radicals, meaning they neutralize the electrical charge and prevent the free radical from taking electrons from other molecules.
Foods Rich in Antioxidants Antioxidants are abundant in fruits and vegetables, as well as in other foods including nuts, grains, and some meats, poultry, and fish. Beta-carotene: Found in many foods that are orange in color, including sweet potatoes, carrots, cantaloupe, squash, apricots, pumpkin, and mangos. Some green, leafy vegetables, including collard greens, spinach, and kale, are also rich in beta-carotene.
Foods Rich in Antioxidants Lutein: best known for its association with healthy eyes, is abundant in green, leafy vegetables such as collard greens, spinach, and kale. Lycopene: Apotent antioxidant found in tomatoes, watermelon, guava, papaya, apricots, pink grapefruit, blood oranges, and other foods. Estimates suggest 85 percent of American dietary intake of lycopene comes from tomatoes and tomato products.
Foods Rich in Antioxidants Selenium: A mineral, not an antioxidant nutrient. However, it is a component of antioxidant enzymes. Plant foods like rice and wheat are the major dietary sources of selenium in most countries. The amount of selenium in soil, which varies by region, determines the amount of selenium in the foods grown in that soil. Animals that eat grains or plants grown in selenium-rich soil have higher levels of selenium in their muscle. In the United States, meats and bread are common sources of dietary selenium. Brazil nuts also contain large quantities of selenium.
Foods Rich in Antioxidants Vitamin A: Found in three main forms: retinol (Vitamin A1), 3,4-didehydroretinol (Vitamin A2), and 3-hydroxy-retinol (Vitamin A3). Foods rich in vitamin A include liver, sweet potatoes, carrots, milk, egg yolks, and mozzarella cheese. Vitamin C: Also called ascorbic acid, and can be found in high abundance in many fruits and vegetables and is also found in cereals, beef, poultry, and fish.
Foods Rich in Antioxidants Vitamin E: Also known as alpha-tocopherol, is found in almonds, in many oils including wheat germ, safflower, corn, and soybean oils, and is also found in mangos, nuts, broccoli, and other foods.