How bad is smoking to human health, and is it associated with cancer?
 |
Smoking is the most preventable cause of premature death for people. In fact, one of five deaths of Americans can be directly attributed to tobacco smoking. Almost 90 percent of all lung cancers in American men (80% in women) are due to smoking, and smoking is also highly associated with cancers of the mouth, pharynx, larynx, esophagus, pancreas, uterus, cervix, kidney, and bladder. When tobacco is burned and inhaled the smoke contains thousands of chemicals with dozens of them known cancer causing agents or carcinogens. Clearly, the best thing a smoker can do for himself or herself is to stop smoking as soon as possible. |
Does obesity place us at a higher risk for cancer?
Large studies of populations have indicated that obesity is a significant risk factor for almost all types of human cancer including endometrial, colon, breast, and prostate. Quite simply, individuals who eat less energy and maintain body weights closer to their ideal body weight tend to be at a lower risk for most cancers. Whether increased body fat directly causes cancer is doubtful, but research suggests that some of the chemicals that swollen fat cells release can increase the rate of developing cancer. This is because some of these chemicals are associated with the growth of cells and tissue.
Is dietary fat related to cancer?
Eating a diet with a higher percentage of the calories derived from fat appears to place people at greater risk of many cancers. This may partly be explained by the association between a high fat diet and the development of obesity. However, some researchers believe that a high fat diet exerts an independent effect as well. In addition, diets containing higher amounts of linoleic acid, an essential omega-6 PUFA, have been reported to place people at a greater risk of various cancers.
How is nutrition involved in cancer prevention?
 |
There are many components of the food supply or human lifestyle that have either been shown to or are at least speculated to impact cancer either by increasing or decreasing its occurrence. Those that may provide benefit include vitamins A, E, C, and folate, calcium and selenium, dietary fibers, omega-3 fatty acids, carotenoids, organo sulfur compounds, and polyphenolic substances. Those that possibly increase the risk of cancer include fat, alcohol, smoking, nitrites, aflatoxin, and pesticides. Many chemical carcinogens can be rendered powerless by optimizing normal cell defense mechanisms such as antioxidants and detoxifying enzyme systems. Optimal nutrition helps assure us of maximal defensive mechanisms. Furthermore, once cancer has established itself, optimal nutrition has been reported to slow and in some situations reverse the spread of cancerous cell growth. |
Why are antioxidants important in cancer prevention?
Vitamin C, carotenoids, vitamin E, selenium, copper, zinc, and manganese are very important factors in normal antioxidant activities. These factors then become very important in cancer prevention as many cancers begin with free-radical damage to key cell components, such as DNA. All of these factors can be found to some degree in fruits and vegetables, which probably is a primary reason why people eating a diet rich in fruits and vegetables are at a lower risk of most cancers. Also, people eating a diet rich in fruits and vegetables tend to eat less fat and exercise more frequently. Whether there is a need for antioxidant supplementation is the subject of much debate.
Can vitamin C decrease the incidence of cancer?
 |
Among all of the vitamins, perhaps vitamin C has received the most attention as an anticancer agent. Much of the research involving vitamin C and cancer in people has been correlation studies, which are used to determine an association between the two or more entities. In regard to cancer of the mouth, larynx, esophagus and colon as the vitamin C content of the diet increases, the risk for these cancers decreases two to three times. In more direct research studies it seems that individuals getting less than 80 milligrams daily appear to be at greater cancer risk than individuals with higher levels of intake. |
The true impact of higher levels of vitamin C intake is difficult to assess on an individual basis and thus a more general recommendation of 400 mg of vitamin C daily seems reasonable for general health promotion. One important consideration for vitamin C consumption is recognized in smokers. Researchers have reported that it may take as much as a four to six times greater vitamin C intake for smokers to achieve the same blood level of vitamin C as nonsmokers. This is especially important as cigarette smoke contains an abundant supply of free radicals and free-radical-creating substances, and appears to increase the risk for many cancers, especially lung cancer.
