Dietary modulation of experimental neoplastic development: role of fat and fiber content and calorie intake.
Cancer is still one of the major causes of death in the industrialized countries but locally prevailing lifestyles may dictate the kinds of cancer seen among populations of different geographical areas. Dietary habits and, in particular, the nature and/or the amount of fat, calorie and/or vegetable fiber which are consumed in these countries are among the most frequently quoted etiological factors which may account for this situation. Epidemiological and experimental evidence has accumulated which, even though it can be used to support these conclusions, is still a matter of considerable debate. Modulation of neoplastic development is a concept which has been elaborated to overcome the fact that many experimental observations are not really taken into consideration by the classical 2-step theory of carcinogenesis. It is defined as the effect of any treatment which given before, during or after the initiation of a full carcinogenic process modifies the pattern of neoplastic development as evaluated by the kinetics of appearance, the incidence and/or the yield of histologically characterized malignant tumors. It is said to be positive or negative depending on whether it accelerates or slows down the process and increases or decreases the yield of malignant tumors respectively. From a review of the available experimental data, it is concluded that fat per se has, most probably, no modulating effect but that unbalanced diets rich in lipids could act as a positive modulator of chemically induced carcinogenesis by virtue of their capacity to cause a break in metabolic and proliferative homeostasis; that vegetable fibers as well as restriction in calorie intake could act as negative modulators of the same process because they could restore or help restore this homeostasis. It is thus proposed that to maintain dietary balance either by increasing fiber and/or by reducing total calorie intake is the most effective way to negatively modulate chemically induced carcinogenesis in experimental animals. To make the same recommendation to humans could most probably help preventing major cancers like breast and colon cancers.
Roberfroid
M B
MB
Université Catholique de Louvain, School of Pharmacy, Unit of Biochemical Toxicology and Cancerology, Brussels, Belgium.
D000818:Animals; D015197:Carcinogenicity Tests; D004041:Dietary Fats; D004043:Dietary Fiber; D002149:Energy Intake; D006801:Humans; D009374:Neoplasms, Experimental / Q000209:etiology* / Q000517:prevention & control
D004041:Dietary Fats; D004043:Dietary Fiber