Update on Dietary Fat and Cancer 1

Abstract

The usual response of both researchers and the lay public to the association of dietary fat and cancer is that consumption of the mac-ronutrient leads to increased risk of the disease. It is our position that the data, while suggestive of an association with certain tumors, are not overwhelmingly in favor of this hypothesis. This review will attempt to add our perspective on this issue and will cite recent developments in both basic and epidemiologic research that are significant in relating dietary fat with cancer.

The strongest evidence for a statistical association of fat consumption and cancer incidence is derived from international comparisons. These data are based on per capita nutrient availability, rather than actual consumption, and on cancer mortality data that are not necessarily accurate (especially in the less affluent countries that have lower reported rates of certain cancers) or age adjusted. In any scattergram of deaths from cancer of the breast or colon versus dietary fat there are points on the graph where one can find countries whose per capita fata availabilities are identical but whose cancer mortality varies several-fold (Fig. 1) (1). Likewise, if one compares countries with similar death rates from the putatively diet-related tumors one can find countries whose fat availability differs by several hundred percent. The search for reasons behind such discrepancies may be more revealing than ignoring such “outliers” from the regression equation. While there probably are real differences in specific cancer death rates between affluent and poor countries, it is equally important to consider the life expectancy in these countries as well. All the affluent countries with the high cancer rates also have the longest life expectancies (2). Likewise, the countries with the lower rates of cancer generally have significantly shorter life expectancies.