First, the bad news: Overall, the incidence of cancer continues to rise in this country, with more than 1 million new cases diagnosed every year. Approximately four out of every 10 Americans will develop cancer at some point in their lives, and about half of these will die of the disease. Cancer is second only to heart disease in claiming lives in the United States. Sadly, an estimated two-thirds of cancers are associated with lifestyle practices. Most experts agree that the typical American diet is even more signifcant than tobacco use in creating these deadly statistics. It is estimated that one-third of all cancer deaths are related to diet; another third of cancer deaths are related to other lifestyle factors such as smoking and suntanning.
The good news, of course, is that there are choices we can make that will dramatically decrease our risk of developing cancer. The single most important thing we can do is to modify our diets. Many forms of cancer have been linked to diet by comparing their frequency in populations around the world whose eating habits differ from our own. For example, people in rural China have much lower frequencies of breast, colon and prostate cancer. Only 15 percent of the calories in their diet are derived from fat, as compared with about 40 percent for typical American fare. They also eat less protein, including one-tenth as much protein from animal sources, e.g. meat and dairy products. The excellent health and low cancer incidence of Mediterranean populations are generally attributed to a diet high in fruits, vegetables and whole grains, with moderate intake of alcohol, low consumption of animal products (especially red meat) and the use of olive oil instead of saturated fats like butter or margarine. In one Italian study, people who ate lots of fruits and vegetables were only one-fifth as likely to develop most of the common cancers.
We don't really know why fruits and vegetables seem to protect against cancer. They contain high levels of the anti-oxidant vitamins, vitamins C and E and beta-carotene, that prevent cancer-causing damage to cells. However, giving these vitamins in high doses as dietary supplements has so far yielded mixed results in clinical trials. Nonetheless, many studies find a strong and consistent benefit to eating a variety of fruits and vegetables for the prevention of a wide range of cancers. It seems that an apple a day really does keep the doctor away.
Fortunately, even very small changes in the diet, when practiced over a lifetime, can significantly decrease the risk of cancer. We all know that making dietary changes can be difficult. Here are some suggestions that could help:
*Try making small changes one at a time. For example, consider buying 2 percent milk instead of whole milk.
*Choose chicken or turkey more often, and remove the skin before cooking.
*Use olive oil instead of margarine or butter in cooking. Choose cooking methods that don't add fat to your foods, such as baking, steaming or microwaving.
*Each week, try out one new vegetable. Discover kohlrabi, collards, turnips or rutabagas.
*Replace white bread with bread made from whole grains.
*Read product labels and select foods higher in fiber and lower in fat.
*Be very patient with yourself.
For more information on cancer prevention and treatment, check out Emory's MedWeb at http://www.emory.edu/ WHSCL/medweb.oncology.html. MedWeb has really impressive links to cancer databases and information resources all over the world.
Linda Gooding is program director of immunology in the School of Medicine. The publication of Wellness is coordinated by the Seretean Center for Health Promotion.