When words like "cure" and "prevention" appear in the title of a book about a chronic, disabling or life-threatening disease, they often enrich authors and publishers at the public's expense. Such is likely the case with a current best seller, "The Breast Cancer Prevention Diet" by Dr. Bob Arnot, the medical correspondent for NBC.
The book's premise -- that adopting a diet rich in soy, flaxseed and fish oils can prevent breast cancer -- has been soundly denounced by breast cancer researchers and patient advocates alike as promising something it cannot possibly deliver.
Eating to Reduce Cancer Risk No food can prevent cancer, but a diet that emphasizes fruits, vegatables and whole grains lowers the risk. Experts recommend these foods:
Dried beans Tomatoes Broccoli Cabbage Milk Salmon Carrots Green tea All dark leafy vegetables Garlic and onions Whole grains All-bran cereal All fruits, especially apples, oranges, strawberries and grapes Red peppers Olive oil
As Fran Visco, president of the National Breast Cancer Coalition put it, "There is no breast cancer prevention diet," and the basis for Dr. Arnot's assertion is too flimsy to warrant a radical dietary shift based on a "bet," as he put it, that it will deliver the goods.
Faced with an onslaught of criticism, Arnot now says he should have used the words "risk reduction" instead of "prevention" in his book title. Critics say the book overextends laboratory findings that have yet to be confirmed in women, suggests dietary changes that have not been tested for long-term safety and intimates that, counter to all rules of sound medical science, it is foolhardy to wait for definitive proof of the effectiveness and safety of the diet.
The Cancer-Diet Link
Arnot is not wrong in suggesting that diet plays an important role in the prevention of cancer, including breast cancer. The American Cancer Society estimates that diet is a primary factor in a third of cancer deaths. That estimate is derived from thousands of studies of people worldwide and is supported by findings in laboratory cell cultures and animal experiments.
These studies suggest that a reorientation of American eating habits -- to emphasize fruits, vegetables and whole grains while minimizing red meats, total fat and especially saturated fats and alcohol -- can significantly reduce the likelihood of developing most of the common cancers like those of the colon and rectum, lung, bladder, stomach, esophagus, mouth, throat and breast.
What cannot be said is that adopting a particular diet can assure that you won't get cancer or that, if you do, the diet will prevent the cancer from recurring.
Last year the American Institute for Cancer Research and the World Cancer Research Fund released an analysis of more than 4,500 studies that examined the relationship between cancer, diet and exercise. The conclusion, as summarized in the current issue of Nutrition Action Health Letter: "While there are no guarantees, there is plenty you can do to cut your risk." Simply eating more fruits and vegetables, for example, can eliminate about 20 percent of cancers, the analysis suggests.
Perhaps most important is that the recommended anti-cancer diet is the very same diet that studies have shown can help to counter heart disease, high blood pressure, diabetes and obesity.
In other words, anyone who is interested in maximizing the chances of staying healthy would be wise to consider adopting a diet rich in whole grains, fruits and vegetables that are loaded with fiber, vitamins and minerals and other cancer-fighting chemicals that occur naturally in plant foods. A protective diet would also be moderate in animal protein -- especially red meats -- and low in fat, saturated fat, simple sugars and alcohol.
In contrast to the low-carbohydrate scheme advocated by Arnot, such a diet is rich in carbohydrates -- not sugars, of course, but the complex carbohydrates, or starchy foods, particularly in their natural, unrefined, fiber-rich state. This is also a diet that can help fight obesity, which is strongly linked to an increased risk of breast, uterine and other cancers. Dietary Do's
The cancers most directly linked to diet are those that arise in lining tissues throughout the body, especially cancers of the colon and rectum, lung, bladder, stomach and, to a lesser extent, the breast, uterus and prostate. The following dietary suggestions are based on the strongest associations established in studies:
FRUITS AND VEGETABLES
Evidence in people has accumulated rapidly in recent years to support the protective role of plant foods against most cancers. The average American eats only about three or four servings a day of vegetables and fruits, while five servings, and preferably nine, are recommended. Especially helpful are yellow, dark-green and orange vegetables rich in carotenoids; fruits like citrus, tomatoes and strawberries that are rich in vitamin C, and all the cabbage family vegetables like broccoli, brussels sprouts, cauliflower, collards, kale, bok choy and mustard and turnip greens. Such foods are linked to lower risks of lung, stomach, colon and rectum, oral cavity, esophagus and, to a lesser degree, breast, bladder, pancreas and larynx cancers.
Garlic, onions and leeks contain allium compounds that help ward off cancer, especially breast cancer. To reduce loss of the protective chemicals, these vegetables should be cut up and let stand for 10 minutes before they are cooked. Other recent findings suggest that the risk of prostate cancer can be reduced by eating lots of cooked tomato products, including ketchup, that are rich in a carotenoid called lycopene and foods rich in the mineral selenium, like meats, fish, grains and seeds.
SOY AND OTHER DRIED BEANS
These contain plant estrogens that may be beneficial in reducing the risk of hormone-related cancers, including breast, uterine and possibly ovarian cancer. A soy-rich diet may in part explain why Asian women have a low risk of these cancers. Dried beans may also help against colon cancer. But experts say that beans are most likely to be protective when used in place of meats and when the rest of the diet is low in fat.
WHOLE GRAINS
Wheat bran in whole-grain cereals and breads is strongly linked to reducing the risk of developing colon and rectal cancers, probably because they speed the passage of wastes and limit exposure of the lower gut to cancer-causing substances.
OTHER HELPFUL FOODS
The list of possible dietary cancer weapons keeps growing. Among recent additions are green tea, olive oil (linked to a lower risk of breast cancer when used in place of other fats) and milk and other foods rich in calcium and vitamin D (linked to a reduced risk of breast and colon cancer). Though the evidence that flaxseed and fish oils can reduce the risk of developing breast or any other cancer is still highly preliminary, there are many other health benefits associated with eating more fish.
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