"At 3 weeks after tumor transplantation, the fish oil diet and the safflower oil diet had induced, respectively, 10- and 4-fold more metastases (number) and over 1000- and 500-fold more metastases (size) than were found in the livers of rats on the low-fat diet."Here's a later one that cited it and added to it:
- Dietary Omega-3 Polyunsaturated Fatty Acids Promote Colon Carcinoma Metastasis in Rat Liver, Cancer Research 1998
Dietary Fatty Acids Modulate Chronic Colitis, Colitis-Associated Colon Neoplasia And COX-2 Expression In IL-10 Knockout Mice, Nutrition, 2006
Mice were fed chow supplemented with:
- Corn oil (control)
- Olive oil
- Fish oil
- "The average colitis score was higher in the Fish Oil than in the Corn Oil group."
- "The incidence of severe colitis (score ≥ 3) was significantly higher in the Fish Oil group than in the Corn Oil and Olive Oil groups (50% versus 7.7% and 3.7%)."
- "Aberrant crypt foci and crypt index were significantly higher in the Fish Oil Group than in the Corn Oil group."
- "Dysplasia [abnormal, precancerous] was more frequent in the Fish Oil group and less frequent in the Olive Oil than in the Corn Oil group (47% and 4% versus 15%)."
"[In mice], fish oil exacerbates chronic colitis and colitis-associated premalignant changes."They used corn oil for the control group. But the corn oil group actually performed worse than the olive oil group. Perhaps it was a function of type of fat? - Both corn oil and fish oil are high in polyunsaturated fat, olive oil is higher in monounsaturated fat.
The trend I see in these and other studies is that dietary fat has some association with cancer, that the type of fat matters (e.g. in colon cancer, polyunsaturated fat seems more problematic), and that certain individuals, especially those with a genetic predisposition, are at increased risk for cancer when they consume certain fats. A low-fat diet, which is by default a high-carbohydrate diet, tends to be protective.
I have a human study I'll post shortly.
Fish oil has become a profitable business, not only because of increased consumer demand, but because it can be produced from exploitation of waste products from other industries - input costs are low.