Abstract
An assessment of colorectal cancer prevalence in different countries strongly implies that overeating a diet that comprises red and processed meat as well as a sedentary lifestyle could raise the risk of colorectal cancer. On the contrary, good nutrition, healthy body weight, as well as, physical fitness could significantly lower cancer risk. This paper explores the reasons why a strict diet together with changes in lifestyle could significantly reduce the risk of cancer.
Cancer versus Diet and Lifestyle
Over 500,000 people in North America die from cancer annually. Jemal, Murray, Siegel, Thun, Ward and Xu (2007) state that about 23% of deaths which occur in the USA are cancer-related, which makes it the second most prevalent cause of death in the country. This trend is predicted to increase as many countries become industrialized and as people continue to adopt a sedentary lifestyle and feed on a poor diet. According to Gohde (2011), previous studies have shown that in most Western countries, people have changed their diet, and have generally increased their intake of meat, fat, alcoholic beverages, sugar, fruit juice as well as vegetable oils with a decrease in eating of starchy staple foods. Physical activities have also reduced considerably. These have increased the rates of cancers of the prostate, colorectal, lung, breast as well as endometrium (Gohde, 2011). Cancer can affect anybody, whether man or woman, and the risk increases with age. Previous studies have shown that lifestyle changes could lower colorectal cancer risk by about 60-80% (Annon, 2008).
People have often asked whether it is possible to prevent and treat cancer naturally without possible side effects, I would say simply, yes. To cure cancer, one needs to eat vegetables and freshly grown fruit and maintain the physical fitness of the body. Cancer occurs due to weakness in the immune system, and as such, it can only be prevented by strengthening the immune system naturally (Lomangino, 2008). For example, colorectal cancer, which is the cancer of the colon, is preventable since it develops from polyps that grow on the lining of the rectum and colon. It is the lifestyle and diets that people have adopted that increase the risk of cancer.
Smoking increases the risk of developing cancer such as lung, colorectal, and throat cancer. According to the American Cancer Society smokers are the most at risk of dying with colorectal cancer as compared to nonsmokers. It is estimated that tobacco smoking causes up to 25-30% of cancer deaths (Aggarwal, Anand, Harikumar, Kunnumakkara, Lai, Sundaram, Sung & Tharakan, 2008). A study that was done by the American Cancer Society found that male smokers were over 30% at risk of dying from colorectal cancer than nonsmoking men. The same study also established that women who smoke are more likely to suffer from cancer-related cases by over 40% as compared to those who do not smoke at all. This proves that change in lifestyle, which in this case is keeping away from smoking could greatly reduce the risk of developing cancer in both men and women.
Physical inactivity also increases the risk of developing cancer. People whose lifestyles do not involve any physical activity and do not engage in physical exercise face the risk of developing cancer. This means that those who consume low-fiber foods and are physically inactive face a greater risk of developing the disease. Regular physical activity lowers an individual’s risk for cancer diseases as well as many other cancer-related diseases. For example, regular exercise reduces the possibility of developing polyps in the rectum/colon. It also helps keep a healthy weight. Several cancer diseases are associated with obesity. Being overweight or obese could raise the levels of a number of hormones in the body, and this may increase the risk for some cancer diseases (El-Safadi & Muenstedt, 2010). Obesity is linked t increased cancer deaths from colon, esophagus, breast, pancreas, kidneys, liver, gastric cardia, prostate as well as, endometrium cancers (Aggarwal, et al., 2008). Diets that consist of high-fat values increase the risk for obesity and several cancer diseases (Koretz, 2007). It is also estimated that obesity causes about 14% of cancer-related deaths in men in the USA. In women, the percentage is even higher than of men by about 6% (Aggarwal, et al., 2008). Thus, regular exercise should also be coupled with eating a low-fat diet.
National Institute on Alcohol Abuse and Alcoholism reports that drinking heavily may also contribute to the development of colorectal cancer, as well as, other cancers of the gastrointestinal tract (Aggarwal, et al., 2008). Aggarwal et al (2008) states that high consumption of alcohol is also a possible cause of cancers of breast, liver, mouth as well as pancreas. The WCRF confirmed that alcoholic drinks increase the risk of the disease in men (Aggarwal, et al., 2008). Koretz (2007) found that people who consume 30 g/d or even more of alcohol per day were more at risk by about 13% for men and 4% for women as compared to nondrinkers. Those who consume over 45 gm of alcohol everyday were even more at risk of developing colorectal cancer as compared to those who do not drink alcohol at all by about 70%. People who drink beer and spirits are more at risk as compared to those who drink wine. About 25-68% of the upper aerodigestive tract cancers are caused by high alcohol intake (Aggarwal, et al., 2008). Out of these, about 80% can be prevented by not drinking alcohol and smoking cigarettes (Aggarwal, et al., 2008). Therefore, to lower the risk of developing cancer, it is advisable to drink in moderation.
Strict diet could also help reduce the risk of developing cancer (Hord & Williams, 2005). According to a study that was carried out by Calle, Chao, Connell, Flanders, McCullough, Rodriguez, Sinha and Thun, high intake of red as well as processed meat increases the risk of colon cancer which normally occurs in the large intestine particularly in the distal portion (Calle, Chao, Connell, Flanders, McCullough, Rodriguez, et al., 2005). Regular intake of processed and/or red meat coupled with low consumption of fish, vegetables, fruits, nuts, as well as poultry increases the risk of a number of cancer diseases. Long-term intake of processed and red meat is highly associated with gastrointestinal tract cancer diseases, colorectal cancer as well as prostate, pancreas, breast, bladder and gastric cancers (Aggarwal, et al., 2008). Aggarwal, et al. (2008) states that about 30-35% of cancer-related deaths result from poor diet. Quite the reverse, Calle et al (2005) established that high consumption of fish and chicken reduced the risk of developing the disease, especially rectal and colon cancer. A study that was conducted by the European Prospective Investigation into Cancer and Nutrition in 2005 found that those who often eat fish were less likely to develop colorectal and rectal cancer (Hord & Williams, 2005). Larsson, Orsini, and Wolk (2010) confirmed that eating foods which contain vitamin B6 could possibly lower the risk of colorectal cancer. Those foods include bananas, fortified cereals, seeds, spinach, potatoes, eggs, poultry, fish, fruits and vegetables.
Inadequate vitamin D in the body also increases the risk of cancer, especially colorectal and prostate cancer (Davies, Heaney, Lappe, Recker & Travers-Gustafson, 2007). Those whose hydroxyvitamin D level is lower than 75 nmol/l is at a higher risk of developing breast and prostate cancer. A study conducted by the National Cancer Institute showed that Vitamin D can help reduce risk of cancer. The study revealed that those whose blood levels have less than 50 nmol/l risk developing colorectal cancer (Freedman, Chang, Graubard & Looker, 2007). On the contrary, enough vitamin D lowers the risk of several types of cancer. Vitamin D enhances strength as well as efficiency of the immune system of the body, and hence, reduces the risk of developing cancer. Blood level of 80 nmol/l and above could reduce the risk of breast and prostate cancer as well as colorectal cancer by up to 72% (Freedman, et al., 2007). It is true that the best source of vitamin D is sunlight; however, other foods such as eggs (egg yolk), canned salmon and sardines, and cod liver oil can supplement vitamin D in the body. Giovannucci (2006) states that there is evidence that high concentration 25-hydroxyvitamin D in the extracellular fluid in the blood increases the ability of proliferating cells to regulate their immune response to a variety of microbial stimuli associated with cancer.
Consumption of foods which contain vitamin C also increases the body’s ability to inhibit inflammation and intercellular communication which cause cancer. High concentration of vitamin C in the blood increases cancer chemopreventive activities, thus, lowering the risk for cancer (Tuma, 2010). Vitamin C can decrease the risk of stomach, lung, cervix, pancreas, pharynx, mouth as well as esophagus cancers (Aggarwal, et al., 2008).
Low levels of calcium in the body are also associated with cancer. However, eating of calcium food supplements significantly reduces all-cancer risks (Davies, et al., 2007; & Vangsness, 2006). A study done by Davies, Heaney, Lappe, Recker and Travers-Gustafson at the Osteoporosis Research Center confirmed that high calcium intake could greatly reduce cancer risk particularly colorectal cancer since it provides a luminal effect on intestine walls (Davies, et al., 2007). The best sources of calcium include dairy products, green vegetables such as kales, broccoli, turnip greens, Chinese cabbage among others. Dried beans, nuts, canned sardines and salmon and calcium-enriched food products such as fruit juice, bread and cereals are also important calcium food sources.
In contrast, some studies have showed that high consumption of dietary fiber which includes vegetables, fruit, cereals as well as other high fiber foods does not decrease the risk of colon cancer and several other cancers. Until recently, it had been thought that intake of such foods could reduce the risk of developing the disease. However, a study conducted in a period of 16 years found that fiber rich diet has no contribution in colon cancer prevention (Baron, Bergkvist, Berrino, Buring, Colditz, Hunter, et al., 2005). These findings are supported by a meta-analysis study that was conducted in 2005 (Baron, et al., 2005). Harvard School of Public Health reports that fiber rich diet may only lower the risk of developing conditions such as diabetes, constipation, heart disease as well as diverticular disease (Harvard School of Public Health, 2011).
Again, it is not possible to prevent cancer in some individuals since it is also hereditary. People with family history of cancer particularly those who have had close relative(s) die of cancer under the age of 55 years are at high risk of developing cancer. About 5-10% of cancer-related deaths are linked to genetic defects (Aggarwal, et al., 2008). Such genetic-related cancer can not be prevented by improved diet or changes in lifestyle.
Radiation from the sun especially the ultraviolet light, X-rays used during therapeutic purposes, and radioactive nuclei from uranium and radium also cause about 10% of cancer cases (Aggarwal, et al., 2008). Some cancer diseases induced by radiation include skin, breast, lung, leukemia, sarcomas, thyroid, as well as, lymphoma cancers. People are normally exposed to these radiation sources meaning that it is not possible avoid electromagnetic rays from entering the body.
Another major cancer risk factor is the infection-related inflammation which comes from viruses associated with cancer. It is predicted that about 17.8% of neoplasms are related to infectious agents (Aggarwal, et al., 2008). Cancer-related viruses are the major cause of cervical, liver, skin, lymphoma, anogenital and sarcoma cancers. Viruses are spread and normally hard to control even by modifying the diet or changing lifestyle.
Environmental pollution is also another major cause of cancer which can not be controlled by modifying the diet. Outdoor and indoor air pollution release hydrocarbons and volatile organic compounds which increase the risk of cancers, particularly lung cancer. Exposure to nitric oxide, PAH containing air, pesticides, motor vehicle exhaust fumes and volatile organic compounds increase the risk lung cancer, sarcoma, leukemia, and lymphoma cancers (Aggarwal, et al., 2008).
Despite the various causes of cancer, significant percentage of cancer-related deaths can be prevented by improving diet to boost the immune system. Specific substances found in vegetables, fruits, fish, cereals and other high fiber foods if taken in the right quantity can prevent cancer; and numerous studies conducted on the same have confirmed that it is possible. If proper diet is combined with physical activities and abstinence from alcohol and tobacco, then cancer can be prevented and cured.
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