Effects of dietary fat on long‐term growth and mammary Tumorigenesis in female Sprague‐Dawley rats given a low dose of DMBA

Abstract

The effects of dietary fat on experimental mammary cancer have typically been observed in relatively young animals. However, in human populations, breast cancer incidence and mortality are highest in postmenopausal women. To develop an animal model that stimulates the human situation more closely, female Sprague-Dawley rats were given a relatively small dose (1.5 mg) of 7,12-dimethylbenz[a]anthracene (DMBA) at 50 days of age while on a semipurified diet containing 3% sunflower-seed oil. One week later, half of the 70 rats were transferred to a diet containing 20% sunflower-seed oil. Very few mammary lesions appeared until about 35 weeks after administration of DMBA, at which time palpable mammary nodules began to appear in many of the animals on the high-fat diet. More than half of the animals in this group had developed nodules by Week 41, whereas the other half of the animals on the low-fat diet developed nodules by Week 46. Rats on the high-fat diet gradually became much more obese than those on the low-fat diet and were significantly heavier at the time they developed lesions. The incidence of nodules continued to increase in both groups and reached 100% in the group fed the high-fat diet by Week 55, with a 70% incidence of adenocarcinomas. At this time, 79% of the animals on the low-fat diet had palpable nodules without a plateau in incidence being reached. On autopsy, adenocarcinomas were found in 57% of animals on the low-fat diet.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of Effects of Diet on Mammary Cancer: Efficacy of Various Preventive Agents and Metabolomic Changes of Different Diets and Agents

“…1A and B; Table 1). These data are not surprising, based on extensive data showing that giving HFD ad libitum yields a higher tumor incidence and multiplicity in this model (26,27). This may be due in some part to the increased body weights achieved in rats on a HFD, although this weight gain was not profound.…”

Uterine Fibroids and Diet

“…Additionally, a study on African-American women reported a protective role of frequent milk and milk product intakes per day on myoma onset and growth, showing also a lack of association for ice cream, butter, and cheese consumption and a weak inverse association for yogurt intake [25]. In fact milk components, such as calcium and butyric acid, seem to have antiproliferative effects on myoma cells [65,66].…”

Food use and health effects of soybean and sunflower oils.

“…Jacobson et al [187] tested the promotional ac tion of diets providing 3 and 20 wt% (7 and 39 en%) SFO in Sprague-Dawley female rats initiated with a low dose (1.5 mg) of DMBA. A typical study from this laboratory suggests a latency (50% incidence) of 10 weeks following an initiating dose of 5 mg DMBA for rats receiving a 20 wt% fat diet [172].…”