Wednesday, January 13, 2010

Corn Oil, Not "High-Fat," Causes Inflammation

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.

13 comments:

  1. "However, the fat used in the study came entirely from corn oil."

    Does the study actually spell that out? This is terrible! Now the general population will once again be able to spout another "proof" that we paleo-eaters are wrong.

    ReplyDelete
  2. AJ,

    Yes it does. If you follow the link embedded in "the study" above, you can read the methods section, where this quote is found:

    "Mice consumed ad libitum a semipurified AIN-76A control diet for 2 wk and were then randomized to either the AIN-76A control diet (control group) containing 5% corn oil, 5 mg/g calcium, and 0.025 µg/g cholecalciferol or a Western-style diet (WD group), a modified AIN-76A diet containing 20% corn oil, 0.5 mg/g calcium, and 0.0125 µg/g cholecalciferol (Research Diets) (14,15) (Supplemental Table 1)"

    You can also follow links to supplemental table 1 where it is shown that this was the only fat in the study.

    Chris

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  3. perhaps they should have used guinea pigs if they really wanted to look at the effects of corn oil and then translate those results to humans...

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  4. Bluets,

    Guinea pigs have more similar lipid metabolism to humans than rodents, but this is especially true in this case becaue, like humans, they do not synthesize vitamin C. The fact that vitamin C increased in these animals suggests that the corn oil would have proved even more harmful to humans or guinea pigs.

    Chris

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  5. Typical nonsense. It just blows me away that people with advanced training in research methodology could make such blatant mistakes.

    The power of groupthink, I guess.

    ReplyDelete
  6. Mmm, corn oil. Hey Chris. You should come cast your vote in the Dietary Evil Olympics. It's a huge showdown between fructose and vegetable oil right now.

    http://180degreehealth.blogspot.com

    ReplyDelete
  7. Thanks Matt! I'd vote but I think it's a tie!

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  8. Inflammation is the bodys natural defense infections and injuries. When something goes wrong with the bodys immune system goes to work to inflame the region, which aims to eliminate the attackers or to improve the wound. The inflammation can cause pain, swelling, redness and warmth, but this goes away once the problem is solved. This is a good anti-inflammatory.

    Xanax Online Cheap

    ReplyDelete
  9. I'm going to try to start updating The Daily Lipid at least several
    times a week now, mostly with short posts.

    ReplyDelete
  10. Guinea pigs have more similar lipid metabolism to humans than rodents, but this is especially true in this case becaue, like humans, they do not synthesize vitamin C.

    ReplyDelete
  11. The master antioxidant of the cell, glutathione, is made from three amino acids, the most important of which is cysteine.

    ReplyDelete
  12. Human data shows n-6 are neutral, or even anti-inflammatory when compared to SFA. So I disagree. http://www.slideshare.net/pronutritionist/fats-and-inflammation

    ReplyDelete

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