Реферат: The Connection Between Diet And Cancer Essay

, Research Paper

Cancer is a disease that can affect many different body parts. But no matter which body part is affected, cancer always involves cells that, due to various causes, go through genetic changes such that they start to proliferate wildly. In most forms of cancer the expanding masses of cells form tumors that eventually push against and invade neighboring tissue, disrupting body systems. In the course of time they may metastasize, travel via the blood or lymph to another part of the body where they set up new colonies that in turn grow and invade tissue. Even though terminal diseases such as cancer rely on genetic factors, a healthy diet can be designed specifically for preventing disease and effectively implemented into a person’s lifestyle and should therefore be utilized by everyone who wishes to decrease his or her odds of promoting cancer.

The food that a person ingests often determines whether or not that person is at risk to have or develop cancer. Certain foods promote different cancers in different parts of the body. Diets high in animal protein especially promote cancers of the liver, large intestine, kidney and breast. Diets high in total fat (animal as well as plant – based) are particularly linked to cancers of the large intestine, prostate, breast and pancreas. Inadequate intakes of plant antioxidant vitamins (beta carotene, vitamin C, vitamin E and many other similar substances) are implicated in many cancers. Food components can prevent cancer by mopping up highly reactive chemicals (free radicals) that act throughout the cancer process inhibiting cell division and enhancing the immune system, especially the so-called “natural killer cells”. Food components also reduce the enzyme conversion of chemical carcinogens to active forms, boost the ability of cells to repair any genetic damage and inhibit any ability of cancer cells to break away and invade other tissues. Fruits, vegetables, and grains in general are anti-cancer champions. Virtually all of them are rich in antioxidants and other substances that block cancer at many stages of its development. The plant foods listed below are a few that appear to be great allies in our fight against cancer. Green tea inhibits tumors of the esophagus, breast, skin, colon and liver in rodents. Soybeans are rich in genistein, a phytochemical that appears to prevent small tumors from growing. Genistein apparently interferes with cancer at many points, from controlling cell proliferation to inhibiting angiogenesis, the building of blood vessels that supply nutrients to tumors. Studies have shown it particularly to protect against breast cancer. Broccoli and the cabbage family are full of phytochemicals that fight cancer. One of them, sulforaphane, protects lab animals from breast cancer. It appears to help cancer-fighting enzymes force carcinogens out of cells. And another, phenmethyl isothiocyanate, apparently disarms carcinogens and prevents DNA from damage. Tomatoes are associated with lower rates of several cancers, most particularly lung and prostate cancer. Flavonoids, phytochemicals that give color to fruits and vegetables, may block the ability of cancer-causing hormones to attach to cells. Garlic and onions contain phytochemicals that activate enzymes that neutralize carcinogens. Flax seeds contain lignans that may block cancerous changes. In addition, their oil is rich in omega-3 fatty acids, which may be helpful against a variety of cancers. Brazil nuts are rich in selenium, a mineral that, in population studies, is associated with decreased incidence of cancer. Just one of these crunchy nuts a day is plenty. They are so rich in selenium that eating too many could give you an overdose. Selenium may block both tumor initiation and promotion.

In order to consume most of the above listed foods, a simple and sensible diet must be followed. P. Singer, author of Animal Liberation suggests that an anti-cancer diet should stay clear of meat at all costs and include the following:

Eat at least five to nine servings of a variety of fruits and vegetables each day. These foods are rich in antioxidants that can prevent the initiation of cancerous changes in the cells, and in addition contain a variety of phytochemicals that may work to inhibit cancer in other ways. Make sure to include members of the cabbage family, rich in powerful anti-cancer substances. Increase the amount of fiber in your diet. Since there are different kinds of fiber, eat a variety of whole foods to reap the various benefits they have. Make sure to eat whole grains and beans as well as your daily fruits and vegetables to help protect the gastrointestinal tract. Reduce fat intake to no more than 20% of daily calories. Since fat is known to be a cancer promoter, this is one of the most important steps you can take to protect yourself against cancer. Because fats occur naturally in many foods, use only minimal amounts of added fats in cooking, or on your toast in the morning. If you do use oils, use highly monounsaturated ones such as olive or canola. Since meatseven the leanest cutsare relatively high in fat, it’s difficult to reach your low-fat goal while habitually eating animal-based foods. Choose a plant-based diet, low in pre-prepared foods, which are often high in fat. Particularly avoid smoked foods such as ham and bacon and charred or barbecued meats. Smoking and barbecuing, particularly of protein-rich foods, can create powerful carcinogens. Avoid fried foods. The high heat needed for frying causes cancer-promoting changes in the oils. Eat foods as close to their natural state as possible. Highly processed foods have lost many of their health-promoting nutrients and phytochemicals and may have harmful additives. Limit alcohol intake, which can lead to mouth, esophageal and liver cancers, particularly when associated with smoking. Cut back on coffee. While studies on the coffee/cancer connection are not conclusive, there is some evidence that both caffeinated and decaffeinated coffee are mutagenic. Try to eat organically grown produce. Pesticide residues on common foods may cause 20,000 cancers a year, according to a 1987 National Academy of Sciences report. Children are particularly susceptible. Maintain an appropriate weight for your height and build. Through mechanisms not yet fully understood, overweight people have higher rates of certain cancers.

Even though the above listed diet is beneficial for all types of cancer, specific cancers require specific diets. Almost one in seven American women will get breast cancer. These are frightening statistics, but it turns out that there is quite a lot we can do to keep this common cancer at bay. The cabbage family including broccoli, cauliflower, kale and collardsis are rich in an array of anti-cancer phytochemicals. Some of them, called indoles prompt the body to make benign forms of estrogen that don’t promote breast cancer. Soy foods, such as tofu and miso, also appear to be helpful against breast cancer through a variety of mechanisms. Study after study has demonstrated that women eating high-soy diets have lower rates of this disease. Soy is high in a phytochemical called genistein, which has enough biochemical similarity to estrogen that it can slip, like a key into a keyhole, into estrogen receptors in the breast, locking out the “bad” estrogen. Since most types of breast cancer cells are stimulated by estrogen, a diet that includes soy is a good idea for most women. Citrus fruits may be yet another protector against breast cancer. In an animal trial, limonene, a phytochemical found in citrus fruits, effectively warded off breast cancer. Skin cancer is the most common kind of cancer. Fortunately, most forms of it are usually not deadly. However, the rates of a highly virulent form, malignant melanoma, are rising alarmingly worldwide. In the U.S., melanoma rates have increased 500% between 1950 and 1985. Researchers speculate that soaring rates may be due to the thinning of the ozone layer, and to ideals of beauty that include a deep tan. Dr. Safai, for many years chief of dermatology at Memorial Sloan Kettering Cancer Center, suggests that a diet high in antioxidants may protect against skin cancer. The American Journal of Epidemiology reports that melanoma patients had significantly lower blood levels of vitamin E and beta-carotene than did people without this skin cancer. A diet high in whole grains and fruits and vegetables will amply provide these valuable antioxidants. In addition, a low-fat diet appears to help protect against skin cancer, according to recent research. Green tea might be a good bet, as well. Mice that drank only green tea got an astonishing 88-93% fewer skin cancers, when irradiated with ultraviolet B rays, than a control group that drank only water. Another highly common cancer is prostate cancer. As many as one in five men will get prostate cancer at some point in their lives. Fortunately, there are many dietary adjustments we can make to help avoid this all-too-frequent cancer. High-fat diets, for one, have been implicated in prostate cancer. A study tracking the eating habits of 48,000 men found a powerful correlation between packing away the grease and the advanced form of this disease. Those men who ate the most fat had an astonishing 79% greater risk of getting advanced prostate cancer than did those eating the lowest amounts. The worst foods are red meat, mayonnaise and butter. One of our strongest allies against prostate cancer is the tomato, a component of so many of America’s favorite dishes. Eating a lot of tomato products, which are rich in lycopene, a carotene has strongly been associated with reduced risk for this cancer. For those who don’t care for tomatoes, watermelon and pink grapefruit are alternate and delicious sources of lycopene.

In general, the same diet that is associated with preventing cancer is recommended for cancer patients. Since an anti-cancer diet is low in fats and animal foods and high in a variety of grains and vegetables, it puts less stress on the system while providing an array of immunity-enhancing nutrients. It’s wise to eat this way as much as possible. If due to nausea or other reasons, only small amounts of food can be tolerated, which makes the food that is being eaten even more important to be of the highest quality. Shakes made of a mix of bananas with a half-cup of soymilk can be made quickly and easily in a food processor or blender. Throw a few strawberries or a peach into the mix for a nutritious and truly delicious snack. Beans and lentils, in soup or tacos, make an easy, high-protein meal. Soy products (tofu and soy milk) not only provide protein but also may inhibit angiogenesis, the ability of tumors to build the blood supply they need in order to grow. A series of fascinating experiments showed that the growth of tumors in mice was accelerated when the rodents were fed animal protein, but tumor growth was stopped completely when soy protein was substituted for animal protein.

Cancer is the most feared and deadly disease known to mankind. Many factors involved in the initiation and promotion of cancer are uncontrollable. There is an undeniable, controllable connection between diet and cancer. To avoid increasing the odds of promoting all kinds of cancer, people should avoid animal products altogether and focus mainly on consuming vegetarian products in order to fully satisfy the requirements of the human body.

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