Wellness Focus: Can Diet Prevent Cancer



Can Diet Prevent Cancer?

Cancer. Few words conjure up more terrifying images, despite the fact that many cancers are curable. In a quest to prevent the seemingly uncontrollable, many people look to lifestyle factors that they can control, especially the food they eat.

Causes

What triggers a perfectly normal cell to lose control and become abnormal? Several factors contribute. First, there are environmental agents: substances in our air, water, and food. A chemical or other environmental agent that produces cancer is called a carcinogen. The World Health Organization estimates that carcinogens may be associated with 60 to 90 percent of all human cancers. The hydrocarbons found in cigarette tar are carcinogens. Ninety percent of all lung cancer patients are smokers. Another environmental factor is radiation. Ultraviolet (UV) light from the sun, for example, may cause genetic mutations in exposed skin cells and lead to skin cancer, especially among light-skinned people.

Viruses are a second cause of cancer, at least in animals. These agents are tiny packages of nucleic acids, either DNA or RNA, that are capable of infecting cells and converting them into virus producers. With over 100 separate viruses identified as carcinogens in many species and tissues of animals, it is also probable that at least some cancers in human are due to viruses.

Treatment

Treating cancer is difficult because it is not a single disease and because all the cells in a single tumor population do not behave in the same way. Although most cancers are thought to derive from a single abnormal cell, by the time a tumor reaches a clinically detectable size, the cancer may contain a diverse population of cells. For example, some cells metastasize and others do not. Some cells divide and others do not. Some are sensitive to drugs and some are resistant. Besides chemotherapy, radiation therapy, surgery, cryothermia (freezing), hyperthermia (abnormally high temperature), and immunotherapy (bolstering the body’s own defenses) may be used alone or in combination.

Does Diet Really Matter?

Many lifestyle factors are much more important than diet when it comes to preventing cancer. Don’t let a healthful diet be a substitute for quitting smoking, exercise, practicing safer sex, limiting alcohol intake, and working for a cleaner environment. Dietary factors seem to matter most when cancers of the digestive tract and, to a limited extent, other cancers, such as those of the lung, breast, and prostate. Conveniently, a cancer-prevention diet also appears to reduce risk of heart disease, high blood pressure, and obesity.

Eat Your Fruit and Vegetables

Several studies have associated a diet rich in fruits and vegetables with lower cancer risk. Researchers believe that some carcinogens cause cancer by producing highly reactive oxygen atoms called free radicals, which may cause damage to cell components such as DNA. Fruits and vegetables contain a number of nutrients and chemicals, known as phytochemicals, that appear to interfere with carcinogenesis (development of cancer) caused or promoted by free radicals. They help either by detoxifying carcinogens (cancer-causing substances) or keeping them from penetrating cells or suppressing malignant changes in cells that have been exposed to carcinogens. These cancer-prevention compounds include familiar nutrients like vitamins C and E, carotinoids (vitamin A precursors, including beta-carotene), and selenium. Others include indoles, isothiocyanates, flavonoids, and isoflavones.

Increase your intake of these cancer-prevention compounds by consuming 5 to 9 servings of a variety of fruits and vegetables each day. Try to have a serving from at least three of the following categories: cruciferous vegetables (for example, broccoli, brussel sprouts, cabbage and cauliflower); citrus fruits; dark green leafy vegetables; and dark yellow/orange/red vegetables.

Eat Lower on the Food Chain

Grains, nuts, seeds, and legumes (dried beans and their products) also contain a variety of cancer-prevention compounds. Soy products have provoked a great deal of interest because a high intake of these is associated with lower risk of breast and prostate cancers. Phytoestrogens (plant estrogens) appear to be the ingredients responsible for this effect. Phytoestrogens alter the behavior of sex hormones in both men and women, and the role these hormones play in the process of carcinogenesis.

Avoid Fat and Carcinogens

Carcinogens are found in foods that are smoked, cured, and pickled. Consumption of pesticide residues on fruits and vegetables and in meats may increase cancer risk. Some experts believe that fat intake may be the major and most controllable dietary carcinogen in North America. Red meat consumption has also been associated with increased cancer risk.

Reducing fat intake also help prevent obesity, another cancer risk factor. Statistics indicate that people who are more than 20 percent above their recommended weight have a higher than average risk of many types of cancer. Cancer risk increases with amount of extra weight.

Pass It On

Studies suggest that fiber may help prevent cancers of the colon and rectum. Fiber is plant material that people can digest and is found in plant foods. Fiber may help prevent cancer in several ways. First, it speeds the passage of stools on their journey through the colon, thus reducing the exposure of the colon lining to carcinogens present in these wastes. Second, fiber increases stool bulk and water content, thus diluting carcinogen concentration. And lastly, fat consumption, which is positively associated with cancer risk, often drops when people increase their intake of foods high in fiber.

Name __________________________________________________________ Hour ________

Anatomy/Physiology Date ________

Wellness Focus: Can Diet Prevent Cancer?

Questions: (You will have to look to outside sources, other that the reading material, to answer some of these questions)

1. What percent of lung cancer patients are smokers? What would you imagine would be the cause for the remaining percent?

2. What are some carcinogens mentioned in this assignment? Can you think of any carcinogens not mentioned here?

3. Reflecting on your previous knowledge of how viruses work (specifically retroviruses), how do you think a virus would cause cancer?

4. What are some different therapies used for cancer? What do they try to accomplish (and don’t say “stop cancer”)

5. How does fruits and vegetables affect carcinogens?

6. How many servings of fruits and vegetables should you eat in a day? What is considered a serving?

7. Dietary factors affect which types of cancer the most? What others do they also affect?

8. What are phytoestrogens? Explain using outside sources.

9. What types of food are carcinogens more likely to be found?

10. How much overweight would you need to be to increase your chances of getting a number of different cancers?

11. How does fiber affect the chances of getting cancer?

12. What are some foods you eat more of or things/activities you do that may increase your chances of getting cancer?

13. What are some dietary changes YOU could make that would turn your current eating habits into a cancer prevention diet? Think about what you eat and how you could change your diet.

................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download