http://www.helpguide.org/life/healthy_diet_cancer_prevention.htm#5adaySpecific foods that have the most powerful preventative effect
Certain foods have come to the forefront in the past few decades of cancer research as heavyweights in the battle against cancer. The National Institute for Cancer Research presents an all-star line up of foods known for their effective cancer-fighting properties:
Beans (or legumes), which include lentils and peas, are rich in fiber and contain several chemicals that boost immunity to cancer. Saponins have shown the ability to inhibit the growth of cancer cells in different tissues; protease inhibitors slow down cancer cells from multiplying and suppress proteases, potent cell destroyers; and phytic acid slows the growth of tumors. A study of 3,237 men of different ethnic backgrounds showed that the risk for prostate cancer was 38 percent lower in those who ate the most amount of beans, as compared to those who ate the least amount.
Berries are good sources of vitamin C and fiber, as well as a wonderful substance called ellagic acid, which has been found in laboratory studies to prevent cancers of the skin, bladder, lung, esophagus and breast. Strawberries and raspberries are particularly high in ellagic acid, and blueberries are loaded with a class of anti-oxidants as powerful as any seen. So splurge on berries in your morning cereal.
Cruciferous vegetables include broccoli, cauliflower, Brussel sprouts, cabbage, kale, Swiss chard, and bok choy. Substances in these vegetables have shown the ability to stop the growth of cancer cells in laboratory studies, particularly by regulating a complex system of enzymes that provide a good line of cancer defense. High consumption of cruciferous vegetables has been associated with a decreased risk for lung, stomach and colorectal cancers.
Dark Green Leafy Vegetables like spinach, romaine lettuce, leaf lettuces, kale, mustard greens, collard greens, and Swiss chard all contain high amounts of fiber, folate and a wide range of anti-oxidants which attack and remove hazardous free radicals from the body. Researchers have found that carotenoids in dark green leafy vegetables are effective in inhibiting the formation of breast and skin cancer tumors, and preventing lung and stomach cancer. High folate levels in men who ate diets rich in green leafy vegetables have been correlated with a reduced risk of lung cancer, particularly among men who smoke. Results from the Iowa Women’s Health Study showed a 44%lower risk rate for breast cancer in women who ate the most green leafy vegetables, as compared to those who ate the least.
Flaxseed is the best known dietary source for a substance called lignans, which appear to replicate the action of estrogen in the body. Flax oil does not contain lignans, though they are often added by the manufacturers. In some short-term human studies, flaxseed consumption modified estrogen metabolism such that there appeared to be a possible protective effect against breast cancer. It has also been shown to inhibit the formation of colon, breast, skin and lung tumors in more than one laboratory study. Flaxseed is also high in omega-3 fats essential fatty acids.
Garlic is a natural antibiotic and immune system enhancer, a free radical attacker, and it increases the enzymes that break down carcinogens in the body. Ample research has shown garlic to be one of the best foods to eat for cancer prevention, linking its consumption with slowing or stopping the growth of tumors in prostate, bladder, and stomach tissue, and preventing cancers of the skin and lung. The evidence is particularly compelling for garlic as a preventative agent against prostate and stomach cancers. The Iowa Women’s Health Study found that women who regularly ate garlic had a lower risk for colon cancer. Eat as much of this mighty food as you can stand!
Grapes, especially red and purple varieties, contain high levels of resveratrol, which belongs to a classification of plant chemicals called polyphenols. Resveratrol has been shown to slow the growth of cancer cells and inhibit the formation of tumors in lymph, liver, stomach and breast cells.
Green Tea is the best source of catechins in the human diet, containing about three times as many catechins as there are in black tea. The catechins found in tea selectively inhibit specific enzyme activities that lead to cancer and may also repair cellular damage caused by free radicals. Green tea has been shown to inhibit or block cancer development in colon, liver, breast, and prostate cells. Studies done in Asia show that frequent use of green tea lowers the risk for bladder, colon, stomach, pancreatic, and esophageal cancers. It has also been shown to aid in preventing recurrence of stage 1 breast cancer.
Soy foods, which include tofu, soymilk, soybeans, soynuts, miso (soy paste), tempeh, and soy burgers, are particularly relevant in their effects on hormone-related cancer. Soy contains phytoestrogens, a plant-derived, weaker form of estrogen that some scientists believe replaces the body’s stronger form of estrogen at estrogen receptor sites in the breast, thereby reducing the probability of developing cancer. Several human and laboratory studies have suggested that soy consumption early in life may help protect against breast cancer later in life. However, according to breastcancer.org, many doctors worry that phytoestrogens in soy may increase the risk of women who have already had breast cancer. In another human study, men who said they drank soymilk more than once per day for 20 years were found to have 70% lower prostate cancer risk than men who never drank soymilk.
Tomatoes contain the phytochemical lycopene, which is also found to a lesser extent in watermelon, papaya, and pink grapefruit. More than 35 studies have confirmed a lower risk of cancer as a result of high lycopene and tomato intake, especially cancers of the prostate, stomach, and lung. Lycopene compounds tend to concentrate in tissues of the prostate, so its protective agency there has received the most attention. Tomatoes have the highest anti-cancer potential when taken in a processed form such as tomato sauce, tomato paste, and tomato juice, because of easier absorption. The PDR website reported a study that found that people with the lowest levels of lycopene are three times more likely to get lung cancer than those with the highest levels. African Americans in the same study were found to have eight times the risk of developing cancer when lycopene levels were lowest.
Turmeric is the spice most often used in curry powder. It has an active ingredient called curcumin that has shown resistance to colon, breast,liver, oral, skin, and stomach tumors in laboratory testing on animals.
Yogurt consumed in high quantities has been linked in some population studies to reduced risks of cancer, particularly of the breast and colon.
Food guidelines for cancer prevention
Taking the above points into consideration, a healthy diet for cancer prevention emphasizes the following foods:
Eat at least five servings of fruits and vegetables each day (more are recommended: see
What is the ‘5 A Day’ program and how can it help prevent cancer?). A recent report sponsored by the World Cancer Research Fund and the American Institute for Cancer Study estimated that eating 400 or more grams daily of fruits and vegetables could prevent at least 20 percent or more of all cancers. In addition, those who eat the highest amount of fruits and vegetables have been shown to have one half the cancer risk as those eating the least amounts. Plant-derived foods contain phytochemicals, nutrients that act powerfully to prevent a healthy cell from turning cancerous. Phytochemicals have been studied for their role in boosting detoxification of the cells and stimulating the immune system, as well as their anti-bacterial and anti-viral properties—all hugely helpful in maintaining a healthful inner environment that reduces the likelihood of cancer from forming. Fruits and vegetables are high in vitamin A and beta carotene, the B Vitamins, Vitamin C, and essential minerals.
Choose foods from other plant sources, such as breads, cereals, grain products, rice, or beans several times each day. Limit consumption of refined carbohydrates, including pastries, sweetened cereals, soft drinks, and sugars. Choose whole foods that are rich in complex carbohydrates, vitamins, and minerals over minimally-processed or highly-processed foods.
Eat plenty of fiber. Fiber moves cancer-causing compounds out of the body before they can create harm. It is also thought to dilute potential carcinogens, and may effect hormone production, thus lowering the incidence of hormone-related cancers like breast and prostate cancers. The National Cancer Institute recommends 20-30 grams of fiber per day. Foods rich in fiber are:
Whole grains such as barley and oats, oat bran, and nuts
Apples, bananas, blackberries, citrus fruits, pears, and prunes
Lima , kidney, pinto, and navy beans, chick peas, black-eyed peas, and especially lentils
Brussel sprouts, carrots, tomatoes, potatoes, and broccoli
To help you increase the fiber in the diet, the Cancer Research and Prevention Foundation suggests that you substitute:
brown rice for white
whole wheat bread or rye for white
black beans for ground meat
bran muffin for croissant or pastry
popcorn for potato chips
unpeeled apple for applesauce
baked potato with skin for mashed potato
bean dip or salsa for sour cream dip
Partake of healthy fats. Healthy fats are good for you, in moderation. Olive oil, for instance, has been shown to reduce the risk of breast cancer. The human body needs fat for normal cellular functioning. So when you eat fat, replace saturated fats with unsaturated fats. These include sunflower, corn, and soybean oils (polyunsaturated fats) and canola and olive oils (monounsaturated fats). Two of the most beneficial fats are omega-6 and omega-3 oils, known as essential fatty acids (EFAs). The body cannot manufacture these fats, so they must be provided through the diet. Omega-6 fat is found in abundance in vegetable oils, margarines, mayonnaise, and salad dressings; omega-3 fat in fish, fish oil, and green plant food sources, especially spinach and mustard greens. Omega-3 fatty acids from fish oil have been shown to have an anti-carcinogenic effect in the laboratory.
Strengthen your immune system. The Wellness Community website put together some eating suggestions for maximum immunity. The following chart lists some of the most potent nutrients in the fight against cancer, along with their food sources:
Most Potent Nutrients in the Fight Against Cancer
Nutrient
Food Source
Vitamin A
Fish liver oils, liver
Beta Carotene (provitamin A)
Orange, yellow and dark green leafy vegetables including carrots, cantaloupe, apricots, spinach
Vitamin B2 (Riboflavin)
Whole and enriched cereals and breads. Lean meat, milk, eggs, liver, dried yeast
Vitamin B6 (Pyridoxine)
As for B2, and bananas
Folic Acid
Leafy green vegetables, meats
Pantothenic Acid
Brewer's yeast, legumes, salmon, whole grains
Vitamin C
Citrus; fruits, berries, broccoli, bell peppers
Vitamin E
Leafy green vegetables, egg yolk, liver, wheat germ
Selenium
Garlic, legumes, fish, asparagus
Iron
Liver, peas, egg yolk, asparagus
Zinc
Liver, oysters, soybeans, sunflower seeds
Magnesium
Green leafy vegetables, nuts, seafood
Manganese
Bananas, bran, pineapple, nuts
Protein
Lean meat, poultry, fish, shellfish, eggs, legumes, broccoli, sunflower seeds
Antioxidants
Citrus fruits, legumes, whole grains
Phytonutrients
All plant sources of food, especially dark and brightly colored fruits and vegetables.
‘5 A Day’ program and how can it can help prevent cancer
In 1991, the National Cancer Institute (NCI) and the Produce for Better Health Foundation launched a campaign to increase consumption of fruits and vegetables to 5 to 9 servings a day for every American. “There is no specific fruit or vegetable responsible for reducing cancer risk,” says the 5 A Day for Better Health Program website. “Research shows that it is the regular consumption of a variety of fruits and vegetables that reduces risk.” Five servings is considered the minimum. For men, the recommendation is nine servings per day; for women, it is seven.
To help people gauge their intake, the 5 A Day website defines a serving size as the amount of fruit or vegetable that can fit in the palm of your hand. The following portions are examples of single serving sizes:
A small (3/4 cup or 6 oz) glass of 100% fruit or vegetable juice
A medium-size piece of fruit (an orange, small banana, medium-size apple)
One cup of raw salad greens
1/2 cup of cooked vegetables
1/2 cup of cut-up fruit or vegetables
1/4 cup of dried fruit
1/2 cup of cooked beans or peas
Although the portions sizes are simple to understand, fitting them into a busy lifestyle is another matter. The Cancer Research and Prevention Foundation and the 5 A Day program offer the following tips for meeting 7–9 fruit and vegetable servings per day:
Have a glass of 100% juice in the morning. Add fruit to your breakfast cereal.
Snack on fresh fruit throughout the day. Grab an apple or banana on your way out the door.
Eat a big salad at lunch. Always order lettuce and tomato on your sandwich.
Snack on raw veggies with low-fat dip instead of chips or candy.
Keep trail mix made with dried fruit on hand for a quick snack.
Use the salad bar at your supermarket for precut fruits and vegetables.
Enjoy your favorite beans and peas. Add them to salads. Try black bean and corn salsa for snacking.
Replace creamy pasta sauces, with sautéed vegetables or tomato sauce made with healthy olive oil.
Top a baked potato with broccoli and yogurt.
Add fresh or frozen veggies to your favorite pasta sauce or rice dish.
Eat at least two vegetables with dinner.
Choose fruit instead of a richer dessert.
African Americans are at a higher risk for cancer and other diseases as compared to whites, and are also more likely to die from cancer. At the same time, African Americans consume the least amount of fruits and vegetables of any ethnic group. To help address the disparity in consumption rates, the 5 A Day initiative developed a wellness program for African American churches called Body and Soul. For the past ten years, this program has helped support healthy living, including increased fruit and vegetable consumption. Visit the 5 A Day website for more information or to start a
Body and Soul program at your own church.
A final word about variety. Pay attention to the colors of the fruits and vegetables you choose—green, red, yellow, orange, purple, blue, and white—as nature has imbued each with unique nutrients and phytochemicals that deliver a more complete nutritional benefit when consumed together. Think of assembling a rainbow of colors on your plate; it’s more pleasing to the eye and will give you a good balance of phytonutrients at each meal.
