Breast cancer is the most common cancer among women worldwide. Genetic, environmental, and gene-environment interactions are now considered as key elements in breast cancer etiology. Among the new insights and relationships emerging from recent research data:

For years, researchers had theorized that a high-fat diet was associated with breast cancer, in part because they knew that Asian women, who generally eat a diet much lower in fat than do Western women, have far lower rates of breast cancer. But fat may be a small part of that equation; other factors such as heredity, fewer environmental toxins, and even a high soybean intake may have a greater effect on keeping breast cancer rates low in Asian women.

But some research has shown that when women move from a country with a low incidence of breast cancer, such as Japan, to a country with a high incidence, such as the United States, their breast-cancer risk goes up. Because Japanese women consume lower-fat diets than do U.S. women, researchers have hypothesized that a fat-rich diet is the cause behind the rise in cancer risk.

Also the influence of a diet containing soy protein has been researched with regard to certain health benefits. Women's intake of soy protein is potentially beneficial with respect to risk factors for breast cancer and may in part explain the low incidence of breast cancer and its correlation with a high soy intake among Japanese and Chinese women.

While some researchers disagree, Dr. Peter Greenwald, director of cancer prevention and control at the (US) National Cancer Institute, says it is too soon to dismiss any protection a low-fat diet may provide against breast cancer. There still is "quite a bit of evidence" that high dietary fat along with excessive calories "increases the risk of postmenopausal breast cancer," he says.

If fat is a carcinogen, it probably works very slowly. So a low-fat diet in childhood and early adulthood may be a better cancer preventive than a low-fat diet in middle age and beyond. Of course, you should not eat as much fat as you want. High-fat diets have been clearly linked with two other big killers of women -- heart disease and colon cancer. And although the hard evidence isn't there yet, experts think that a diet high in fruits, vegetables, and grains -- and therefore correspondingly low in fat -- may help prevent cancer and other diseases, perhaps by strengthening the immune system.

Here are some general dietary guidelines: A low fat diet is widely recommended. Fat is likely the culprit with the epidemic proportions of breast, colon and prostate cancer. The incidence of these cancers and others is decreased in cultures eating a low fat, high fiber diet. In a vegetarian type diet the incidence of cancer in general is markedly decreased.

Even in women already having a diagnosis of breast cancer, obesity is an adverse prognostic factor, that is, women who are overweight do not respond as well as do women of normal weight. When you are in the market read the labels regarding fat content. Strive for the lowest fat diet you can reach. Animal meat consumption should be avoided as much as possible. Fish, turkey and chicken should be your source of non-vegetable protein. The majority of medical articles now suggest that we eat complex carbohydrates -- starches that require digestion to break them down to simpler carbohydrates and eventually sugars. Simple sugars should be avoided. Their consumption results in jumps in blood sugar with the body reacting with insulin production and frequently hypoglycemia. Eating complex carbohydrates avoids this. Coarse-grained breads, whole wheat and bran cereals, raw or lightly steamed vegetables, fresh fruits are all in this class of complex carbohydrates.