Dietary alcohol intake does not increase the incidence of experimentally induced mammary carcinoma.

There is considerable evidence from epidemiological studies that even moderate dietary alcohol intake increases the risk of breast cancer in women. The aim of this study was to test the hypothesis that dietary alcohol intake increases the incidence of mammary carcinoma in a rodent model. Two matched groups of female Sprague-Dawley rats were given 7,12-dimethylbenz[a]anthracene 15 mg by gavage when 50 days old. One group of 20 animals was given dietary ethanol at a dose of 4.4 g/kg/day in their drinking water. The incidence of tumors was significantly less in the group given ethanol (P less than 0.001). In those developing tumors, there was no significant difference between the two groups in the mean number of tumors per animal, the tumor growth rate or the time to the appearance of the first tumor. This study fails to support the hypothesis established by previous epidemiological studies.