Nutrition and cancer among American Indians and Alaska Natives.

BACKGROUND: More than a third of all cancers in the United States are thought to be attributable to various nutritional factors, and major changes in nutrition have been experienced by American Indians and Alaska Natives in the past century.
METHODS: The published literature was reviewed to summarize the relationship between diet and cancer, to summarize what is known about the past and current diet of American Indians and Alaska Natives, and to consider whether nutrition might play a role in their current or future risk of cancer.
RESULTS: Epidemiologic studies show a consistent pattern of lower risk for cancers of the colon and lung among those who eat larger amounts of fruits and vegetables and higher risk for cancers of the colon and prostate for those who eat larger amounts of fat. Limited data indicate that the diets of American Indians and Alaska natives are similar to the current average American diet, that is, high in fat and low in fruits and vegetables.
CONCLUSIONS: Diet is an important factor for several major cancers. Although the cancer rates among many Native American groups are currently lower than among non-native Americans, they seem to be increasing. Cancer rates among Native Alaskans are already much higher than for non-native Americans. Nutrition-related cancers are likely to increase in the future among Native Americans as a result of past changes in diet. However, Native Americans may have a stronger cultural basis than do non-native Americans to adopt traditional principles of the value of good foods and physical activity to achieve future nutritional improvements to reduce cancer risk.