This article came from Intelihealth.com (maintained by Harvard Medical School) Causes Of Cancer Scientists have identified many factors that contribute to the development of cancer. Avoiding these risk factors whenever possible could have a significant effect on your chance of getting cancer. The main risk factors include: Alcohol Drinking alcohol has been linked with an increased risk of cancer of the esophagus, oral cavity, pharynx and larynx, and also of the liver, breast, rectum and pancreas. The cancer risk from drinking alcohol is especially pronounced if you smoke or have a high-fat diet. If you drink, it’s important to drink moderately. For men, this means no more than two drinks a day. For women, it’s one drink a day. Bacteria And Viruses A number of cancers have been linked to infectious agents, including parasites, viruses (such as the human papillomavirus and the viruses that cause hepatitis) and the Helicobacter bacterium that causes ulcers. Prevention could be as simple as getting hepatitis vaccinations, practicing safe sex by using a latex condom, and discussing antibiotics with your doctor if you suffer from ulcers. Diet Studies show that between 30 percent and 40 percent of all cancers are related to diet. A number of foods have been shown to increase the risk of a variety of cancers. These include: Foods that are exposed to high temperatures, such as grilled or broiled meats. Cured meats containing compounds such as nitrosamines. Foods high in saturated fat. There’s some evidence that people who have diets high in saturated fats (more than 10 percent of total calories) have a higher cancer risk than those with lower-fat diets. Alcohol can promote several types of cancer by damaging cells in the oral cavity and larynx, or by indirectly affecting the liver, colon and breast. In some cases, not getting enough of certain foods can increase your risk of getting cancer. Fruits, vegetables, whole grains and other plant-based foods contain fiber, complex carbohydrates and other substances that can inhibit tumor formation. For example: Cruciferous vegetables contain sulforaphane, as well as other phytochemicals such as dithiolthiones. These compounds may trigger enzymes that help block damage to cell DNA. The cruciferous vegetables include broccoli, cauliflower, kale, brussel sprouts and cabbage. Garlic and onions have sulfur compounds (allyl sulfides), which trigger enzymes that may help remove carcinogens from the body. Citrus fruits are rich in vitamin C and flavonoids, which may help inhibit cancer cell growth. Soy foods are high in isoflavones, which block some hormonal activity in cells. Diets high in soy products have been associated with lower rates of cancers of the breast, endometrium and prostate. Tomatoes and tomato sauce are high in the phytochemical lycopene, a powerful antioxidant. A diet high in tomatoes has been associated with a decreased risk of cancers of the stomach, colon and prostate. Environmental Factors There’s clear evidence that many environmental factors may contribute to cancer development. These include: Chemicals used in some cleaning agents, paint solvents and deodorizers are believed to be carcinogenic. Chlorinated drinking water has been associated with an increased risk of developing bladder cancer. Nitrate, another chemical in water, has been associated with an increased risk of a blood cancer called non-Hodgkin’s lymphoma. Radon is a naturally occurring, invisible gas that enters through cracks in a building’s foundation and is concentrated indoors. If the gas is inhaled, it may increase the risk of lung cancer. You can buy radon test kits are hardware stores. Family History Virtually all cancers tend to aggregate within families. Close relatives of someone who has cancer have a higher risk of getting that particular cancer and possibly others. In some cases, the increased risk among family members is caused by sharing gene traits that are known to contribute to cancer. In addition, family members may share exposure to carcinogens in the environment, such as cigarette smoke or environmental pollutants in a particular geographic area. Anyone who has a family history of cancer needs to be particularly vigilant about getting the appropriate screening tests. Sedentary Lifestyle It’s been estimated that 32 percent of colon cancers may be linked to low levels of physical activity. Studies have shown that people who get regular exercise are less likely to develop colon and possibly breast and prostate cancer. Research suggests that exercise is protective because it stimulates intestinal contractions (peristalsis), which increase the speed at which stools move through the intestine and out of the body. This could reduce exposure of cells in the colon to potential carcinogens in the stools. Smoking Smoking is believed to play a role in approximately 30 percent of all cancer deaths in the United States, and it causes about 85 percent of lung cancer deaths. About 4,000 different compounds have been identified in tobacco and tobacco smoke. Of these, about 60 are known to cause cancer or to stimulate tumor growth. The only preventive measure is not to smoke. A smoker’s risk of developing cancer decreases dramatically immediately after quitting and continues to decrease every year thereafter. Sun Exposure Exposure to the ultraviolet radiation in the sun’s rays is responsible for almost all cases of basal cell carcinoma and squamous cell carcinoma and is a major cause of malignant melanoma. The best preventive strategies include staying out of the sun as much as possible, wearing protective clothing (including a hat that shields the back of your neck) and using a sunscreen with a sun protection factor (SPF) of 15 or higher. Also, avoid tanning booths, which increase the risk of cancer, and wear ultraviolet light-filtering sunglasses. Last updated September 30, 2000 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.