Breast Cancer: Weighing the Evidence for a Promoting Role of Dietary Fat

Abstract

It has been hypothesized that a high-fat diet promotes the development of postmenopausal breast cancer. This contention is supported by data showing high international correlations between fat intake and breast cancer rates, modest positive associations with a high-fat diet in case-control studies, and animal model studies that have consistently demonstrated that dietary fat influences mammary cancer development at several stages in the carcinogenic process. A number of plausible biologic mechanisms have been suggested that may explain such promotional effects. In contrast, dietary fat intake is unrelated to the risk of breast cancer in cohort studies. The conflicting findings from cohort studies have created uncertainty regarding nutritional recommendations and breast cancer prevention. After reviewing key scientific findings that are relevant to this issue, the following conclusion is drawn: In the absence of data from dietary intervention trials, the weight of available evidence suggests that the type and amount of fat in the diet is related to postmenopausal breast cancer and that the inability to detect associations within populations (cohort studies) is because of measurement error and the relative homogeneity of diets measured. It is expected that the results from intervention trials will clarify this issue.

Role of Lipid Peroxidation in the Epidemiology and Prevention of Breast Cancer

“…In chemically induced mammary tumor animal models, highfat diets are associated with increased tumor incidence, and this effect is diminished by antioxidants (vitamin E and selenium), observations that would support a role for lipid peroxidation (18,19). However, Horvath and Ip (19) reported that, although supplementation of the diet with two antioxidants, vitamin E and selenium, inhibited 7,12-dimethylbenz(a)anthracene tumor development, the indices of lipid peroxidation did not decrease in parallel with tumor incidence in this model (20). The systemic suppression of lipid peroxidation by vitamin E alone was not sufficient to inhibit mammary tumor formation.…”

p53 As a mutagen test in breast cancer

“…A current view is that the mammary tumorigenic-enhancing activities of a high-fat diet is, at least in part, through a caloric mechanism [Welsch, 1994]. Epidemiologic investigations regarding the relationship between the amount and the type of fat consumed and breast cancer have produced conflicting results [Hunter et al, 1996;Clavel-Chapelon et al, 1997;Wynder et al, 1997;Woutersen et al, 1999] and a mechanism by which dietary fat may modulate carcinogenesis has not been elucidated.…”

Dietary attitudes and changes as well as use of supplements and complementary therapies by Australian and Finnish women following the diagnosis of breast cancer

“…It has been suggested that lifestyle factors and dietary habits may modulate the indices of breast cancer progression (Wynder et al, 1963;Gregorio et al, 1985;Holm et al, 1989). Dietary interventions currently under study for their possible effects on breast cancer recurrence emphasise fat reduction and increased vegetable intake (Pierce et al, 1997;Wynder et al, 1997).…”