by Chris Masterjohn
According to a recent article on the Science Daily site, "High Fat Diet Increases Inflammation in the Mouse Colon," a November 2009 study published by researchers from Rockefeller University showed that a diet "high in fat and low in fiber, vitamin D and calcium" triggered an inflammatory process that could lead to cancer in the colons of laboratory mice. The article quoted Peter Holt, one of the authors of the paper, as saying that the study lent support to the hypothesis that "red meat, processed meat and alochol can increase risk of colorectal cancer."
One would think that a study designed to test the hypothesis that fat from red meat could trigger inflammation or cancer would use the type of fat found in red meat — a roughly even mix of saturated and monounsaturated fats. However, the fat used in the study came entirely from corn oil. Corn oil is 56% polyunsaturated fatty acids (PUFAs), 98% of which are omega-6 fatty acids, mostly linoleic acid. By contrast, red meat is less than 3% polyunsaturated fatty acids.
As I've written about in my article, "High Cholesterol and Heart Disease — Myth or Truth?" and in my "PUFA Report Part I: How Essential Are the Essential Fatty Acids?" polyunsaturated fats are uniquely vulnerable to oxidative stress, a condition where molecules rip electrons apart from other molecules, often breaking them into pieces or sticking to them and destroying their functionality.
Mice, unlike humans, can synthesize their own vitamin C. After six months on the high-PUFA corn oil diet, mice had increased levels of vitamin C, which probably protected them from some of the effects of oxidative stress. The master antioxidant of the cell, glutathione, is made from three amino acids, the most important of which is cysteine. After six months on the high-PUFA diet, the mice had higher proportions of their glutathione in the oxidized state and major depletions in the amino acid cysteine and its precursor methionine.
The medical and nutritional establishments in this country used to recommend corn oil but quietly withdrew this recommendation after the LA Veterans Administration Hospital Study showed that replacing butter with polyunsaturated vegetable oils over the course of a long-term double-blind study increased the risk of cancer. Apparently elements of these establishments have no problems continuing to perform studies with corn oil while blaming the effects on "red meat, processed meat and alcohol."
But such is the difference between PR and science.
Read more about the author, Chris Masterjohn, here.