The ACS estimates that smoking causes nearly 30 percent of all cancer deaths in the United States—that is, approximately 166,000 cancer deaths each year. All cancer deaths caused by tobacco smoking could be prevented completely by not smoking and not using smokeless tobacco.
For those who already smoke, quitting will reduce the risk of developing cancer. Studies show that after about ten years of not smoking, a past smoker’s risk lowers to about the level of those who have never smoked.
Studies show that people who exercise regularly have lower rates of cancer than the general population. Moderate activity for just 30 minutes a day enhances the immune system, shortens the time food takes to move through the intestines, and improves body composition and hormone levels. Even relatively mild activities such as daily walks can provide significant health benefits.
After quitting smoking, eating a healthy diet is the best way to lower the risk of cancer. Certain foods have been found to protect against cancer. Among these foods are broccoli, cauliflower, cabbage, tomatoes, soy products, and foods high in vitamins A, C, and E. In addition, green and possibly black teas contain compounds that protect the body from carcinogens. These foods contain substances called antioxidants that block the action of free radicals. Other chemicals in fruits and vegetables are thought to block the cell growth promoting effects of steroid hormones, protecting against cancers of the breast and prostate
To lower cancer risk, diets should include little or no red meat. Other foods to avoid or consume in moderation include sugar, saturated fat from animal products, and salt. Added fats and oils should come from vegetables, such as olives or corn, rather than from animal sources. Carbohydrates should come from whole grains, such as brown rice and whole wheat bread, rather than from processed foods, such as white rice and white bread.
Vegetables, fruits, grains, and legumes constitute a rich source of dietary fiber. Composed of the indigestible cell walls of plant material, fiber acts like a scouring pad to cleanse and flush the digestive tract. Researchers claim it helps eliminate cancer-causing chemicals and may decrease the amount of cholesterol in the blood stream.
The risk of cancer of the esophagus increases with heavy alcohol consumption, and many studies suggest that consuming alcoholic beverages increases the risk of breast cancer as well. Studies show that limiting intake to two drinks a day for men, and one drink per day for women, reduces cancer risk.
Low levels of physical activity have been implicated in colon cancer. Moderate activity for 30 minutes a day enhances the immune system, shortens the time food takes to move through the intestines, and alters body composition and hormone levels. Researchers are studying how these effects might lower cancer risk. Physical activity also helps avoid obesity, which is associated with an increased risk for cancers of the colon and rectum, prostate, breast, endometrium, and kidney. By maintaining a healthy weight through regular physical activity and a healthy diet, individuals can substantially lower their risk for these cancers.
Protecting the skin from the sun’s rays could prevent about 80 percent of all skin cancers. When in the sun for prolonged periods, always wear sunscreen with a sun protection factor (SPF) of 15 or greater, particularly if you have fair skin or freckles. Skin needs protection every day, not just on sunny days. The Skin Cancer Foundation also recommends that people avoid the sun at its peak (from 10 am to 4 pm), seek shade, and cover up with clothing and a brimmed hat.
People also can help prevent cancer by practicing safe sex or abstaining from sex. The human papilloma virus (HPV) linked to cervical cancer is the most common cancer-causing virus in the United States. Minimizing the number of sexual partners, using condoms, or practicing sexual abstinence reduces risk of infection with HPV. Infection with the human immunodeficiency virus (HIV), also sexually transmitted, greatly increases an individual’s risk for cancers of the immune and lymphatic system, such as Kaposi’s sarcoma. Infection with the hepatitis B virus (HBV) is the predominant cause of liver cancer in the United States. HBV is transmitted from person to person through unprotected sexual intercourse with an infected person, or through the sharing of infected needles or other sharp instruments that break the skin. Vaccination against hepatitis B reduces the spread of this virus, which leads to reduced incidence of liver cancer.