Health Matters: Cancer-Fighting Powerhouses
As the evidence linking diet and health accumulates, so does the medical research examining how diet can prevent cancer or slow its growth.
A researcher quotes, “This field didn’t exist until nine or ten years ago, because medicine hadn’t been geared toward prevention-related research.”
Researchers found a link between a high-fat diet and cancer as far back as 1942, when tumours in animals fed a high-fat diet grew more quickly than in a control group.
One researcher gives this example regarding prostate cancer specifically, “The United States and Western Europe have the highest death rates from prostate cancer and the highest per capita fat consumption. In contrast, the Pacific Rim countries with the lowest death rates from prostate cancer have the lowest fat consumption.” However, he notes that when these people move to the West, they lose their edge. Americans born in China or Japan, for example, have an incidence of prostate cancer three to seven times higher than those still living in their homelands.
“Something to do with diet is going on here,” cites a Toronto-area nutrition consultant. But she says that scientists don’t yet understand why. They are looking at whether fatty acids themselves contain carcinogens, whether people who eat a lot of meat consume too few fruits and vegetables (and thereby lose out on their protective effects), or whether it is that high-fat diets tend to lead to obesity, which itself carries a higher risk of cancer.
Dietary benefits may come not only from reducing fat intake, but also in eating foods rich in protective micronutrients. A study done in Sunnybrook Hospital in Toronto added three micronutrients to the diets of mice. The incidence of cancer was reduced fourfold even in the group fed a high-fat diet. These mice were put on this diet almost immediately after birth, suggesting that the later someone started a healthy diet, the smaller the beneficial effects may be. For people who want to start reducing their risk of cancer, they need to start immediately on a diet high in soy products, fruits and vegetables, and cut down on fat and take in fewer calories.
Research suggests that we can lower our risk of getting cancer by exercising daily, limiting high-fat foods from animal sources, and eating mostly vegetables, fruits, and grains. Plant sources of food contain phytonutrients, which aren’t vitamins or minerals, but have important health benefits. Phytonutrients are not available in supplement form, so it is important to eat plenty of foods which contain these cancer-fighting compounds. The following food sources, offer specific cancer-fighting benefits because of the various phytonutrients they contain:
Red fruits and vegetables such as cranberries, tomatoes, watermelon, papaya and red peppers contain lycopene, which protects damaged cells from becoming cancerous. Lycopene is a powerful antioxidant, which gives red fruits and vegetables their colour. Antioxidants neutralize free radicals, which can damage the body’s cells. Research also shows that lycopene in tomatoes can be absorbed more efficiently by the body if processed into a juice or a sauce. The heat produced in processing the tomatoes is what seems to increase its availability to the cells in the body.
In the body, lycopene is deposited into the liver, lungs, prostate gland, bladder, colon and skin. Therefore, lycopene-containing fruits and vegetables are most effective in preventing cancers in these organs. Studies show that Italians who consume large amounts of tomatoes as part of their diet had a lower incidence of digestive tract cancers. Of the red fruits and vegetables, tomatoes were the only ones that lowered the incidence of prostate cancer.
Cruciferous vegetables, such as cabbage, cauliflower, brussels sprouts and broccoli, are rich in sulphoraphanes, which help flush ingested cancer-causing compounds from the body. Sulphoraphanes are also powerful antioxidants. It is the group of sulphoraphanes that contain an extra sulfur atom that are anti-carcinogenic. Unlike tomatoes, broccoli needs to be eaten raw to get the best effects. When broccoli is chewed, it releases this chemical for the body to use. Heating broccoli in the conventional way destroys the enzyme that produces the sulphoraphanes.
Leafy green vegetables, tofu, walnuts, canola oil, pumpkin seeds, and flaxseed contain Omega-3 fatty acids, which help maintain a healthy body and repair diseased tissues. Flaxseed has been shown to have the highest levels of omega-3 fatty acids. Flaxseed needs to be ground up, or chewed very well. If just eating whole seeds, they will pass through the body undigested and not be used. It is best to buy pre-ground seeds if possible. In addition to omega-3 fatty acids, flaxseed contains lignans, an antioxidant which also protect against various cancers. Flaxseed oil is not as beneficial as it does not contain the fibre and lignans that the actual flaxseed contains. Also, flaxseed oil breaks down with heat, so it should not be used to cook with. Ground flaxseed can be used in baking.
Not only does omega-3 fatty acids protect against cancer, but it has many health benefits in preventing heart disease, arthritis, cognitive decline, osteoporosis, diabetes, etc. Omega-3 acids are considered polyunsaturated fats, which are the healthy fats that prevent cholesterol build-up.
Vitamin E is also considered an antioxidant which can decrease the risk of cancer. It occurs naturally in plant-based fatty foods such as nuts, sunflower seeds, safflower, canola, corn and olive oils, wheat germ, leafy green vegetables, asparagus, mangoes, wheat germ and whole grains. Vitamin E also helps to counteract the effects of a high-fat diet. Although, cutting fat from the diet is more beneficial instead of using a supplement to diminish the bad effects of fat in the diet.
Garlic, leeks, and shallots contain selenium and antioxidants, and can help dispose of cancer-causing chemicals. They also protect DNA from harmful substances. These products belong to the family known as alliums. Garlic also has the added benefit of protecting the body from Choose foods made with fresh garlic instead of taking supplements, since a lot of synthesized compounds are added by manufacturers whenever garlic is chopped, crushed, or minced. After crushing fresh garlic, let it stand for 15 minutes before cooking with it researchers have found that this activates a “cancer-fighting” enzyme within the garlic. On the other hand, roasting garlic in the peel may taste great, but heating it in this way destroys the cancer-fighting enzyme.
Alliums contain the mineral selenium which is a crucial antioxidant. Scientists first recognized selenium’s potential cancer-fighting benefits when they noticed that countries whose soils have low levels of selenium (including Canada) also have higher rates of cancer. Selenium is especially effective in reducing the incidence of prostate cancer. In countries with low selenium in the soil, it is recommended that a supplement be taken. But, do not exceed doses higher than 200mcg a day, as higher doses may be toxic and cause other health problems.
Soy protein is high in polyphenols known as isoflavones, which are believed to help prevent certain cancers, especially those cancers that are hormone related, like breast and prostate cancers. The two primary isoflavones in soy which protect against cancer are daidzein and genistein. Polyphenols are powerful antioxidants, which prevent free-radical damage to DNA. In addition to isoflavones, soy also is healthy because it is low in saturated fat, are free of cholesterol and contain omega-3 fatty acids.
Soybeans have been used by man since creation. Only since the 20th century has soy become popular in the Western countries. Soy is the only plant protein that contains sufficient amounts of all nine amino acids. Also, soy contains carbohydrates along with the protein, unlike animal protein which contains high amounts of fat. Even in those people who already had cancer, tumours grew much slower when the daily food intake consisted of at least 40g of soy protein. Soy products that include significant levels of isoflavones include tofu, soy milk, tempeh, miso, and soy powder/flour. Be sure that when you buy soy milk, you do not buy the non-fat soy milk. Soy beans lose some of their beneficial properties when completely defatted. Use either regular or low-fat varieties.
Raw soybeans contain between 2-4 mg of isoflavones per gram. Many of the processed soy products such as soy burgers, soy hot dogs, soy-based ice creams, etc. may not contain significant amounts of isoflavones because of the way the food has been processed. These products contain considerable amounts of non-soy ingredients.