Omega-6 Fat News & Commentary
Research News by Evelyn Tribole, MS, RD
Omega-6 Fat Research News & Commentary

Omega-6 Content in 150 Foods and My Hiatus

I will be taking an extended hiatus. I just got two book proposals accepted for publication (looks like publishing is alive and well, at last). And now I need time to actually write the books! So I won't be responding to comments or e-mails for a while. The research news feed “Latest Omega-6 News” will continue to auto-update, it’s located on the upper right column. In the meanwhile, here are some resources that you might find helpful: Omega-6 Content of more than 150 foods... << MORE >>

Meta-analysis Reveals “Heart Healthy Omega-6 Fat” Increases Risk of Heart Disease

Bottom Line: The research upon which the American Heart Association based their "eat-your-omega-6-fat" advisory, is fatally flawed, according to the results of a meta-analysis study, which showed that a steady diet of omega-6 polyunsaturated fatty acids increases the risk of heart disease and death, especially for women [1]. British J Nutr. Dec 2010.

       [Here's a link to the full post ]
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Meta-analysis Reveals “Heart Healthy Omega-6 Fat” Ups Risk of Heart Disease

Bottom Line: The research upon which the American Heart Association based their "eat-your-omega-6-fat" advisory, is fatally flawed, according to the results of a meta-analysis study, which showed that a steady diet of omega-6 polyunsaturated fatty acids increases the risk of heart disease and death, especially for women [1]. British J Nutr. Dec 2010.

Background: ln 2009 the American Heart Association (AHA) published a health advisory touting the benefits of eating a high omega-6 polyunsaturated fatty acids (PUFA), and ...

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One-Man Tipping Point: How One Scientist is Helping His Community “Nix the Omega-6” and Improve Health

Bottom-Line: One scientist is single-handily changing the way Morgan County, West Virginia eats. His mission is to demonstrate that chronic diseases and their ensuing health costs can be significantly reduced, by lowering dietary omega-6 fats and eating enough omega-3 fats.

Background:Bill Lands, PhD, is a one-man tipping point,with a mission and a motto: ...

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Case Study: 30-Days of High Omega-6 Diet--Stiffens Arteries and Increases Belly Fat

Bottom line: A daring journalist eats a high omega-6 diet for 30-days (think Super-Size Me), which results in stiffer arteries, lowered metabolism, and an increase in belly fat.

Background: Journalist and author, Susan Allport, sold Oprah magazine on the idea of a “super-size me ” version of eating a high omega-6 fat diet for 30 days.  Bravely, she offered to be the human guinea pig.   What ...

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Diets High in Omega-6 to Omega-3 Fats Linked to Obesity

Bottom-Line: Diets high omega-6 to omega-3 fat may lead to obesity, according to results of an animal study. Cardiovasc Psychiatry Neurol. 2009;2009:867041.

Background: Adipose tissue is more than a dormant energy storage depot. Fat cells, known as adipocytes, release chemical mediators, which promote inflammation. This may be the key link between obesity and increased risk of inflammatory diseases.

Emerging research in both animal and human studies indicate that eating excessive amounts of dietary omega-6 fat combined with insufficient amounts ...

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Omega-6 Fats Increase Risk of Blindness (AMD)

Bottomline: Eating a diet high in omega-6 fats, from salad dressing, mayonnaise, and margarine, was associated with increased prevalence of age-related macular degeneration, a leading cause of blindness worldwide. Arch Ophthalmol.2009 Nov;127(11):1483-9

Background: Age-related macular degeneration (AMD) is the leading cause of blindness in the USA, and is expected to increase in prevalence by 50% in ten years.

Previous studies suggest a direct association between vegetable oils and AMD. Omega-6 fats is thought to contribute to retinal ...

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Why Omega-6 Fats Matter to Your Health

BottomLine: Why Do Omega-6 Fats Matter for Health and Disease Prevention?  Find out from pioneer scientist, Bill Lands, PhD. Video presentation, slides, and handout resources provided. (Note, all of this information is provided free for the sake of public health).

BackgroundLearn how most chronic diseases could be prevented by lowering omega-6 fats in the diet and why supplementing with fish oil and omega-3 fats is not enough. 

Scientist, Bill Lands, PhD, cuts to the chase, and provides compelling reasons Americans ...<< MORE >>

Dietary Arachidonic Acid Increases Risk of Parkinson's Disease

Bottomline: A case-control study indicates that eating higher levels of arachidonic acid, the omega-6 polyunsaturated fatty acid, increases the risk of Parkinson's Disease.                      J Neurological Sciences (2009).

Background: Parkinson's disease is a progressive movement disorder of the nervous system, that worsens over time, for which there is no cure. Fatty acids play a critical role in brain function. Previous case control studies indicate an association between eating animal fat and Parkinson's disease. Arachidonic acid, is the omega-6 polyunsaturated fatty acids, which is ...<< MORE >>

Prostate Cancer Growth Increases with Omega-6 Diet, but Slows with Omega-3.

Bottomline: A cleverly designed study shows that high dietary omega-6 fat triggers tumor growth, in an animal model of prostate cancer, while dietary omega-3 fat attenuates.  Neoplasia (2009):11(7):692-699

Background: Prostate cancer is one of the leading causes of death among men in the USA. Previous studies implicate the imbalance of dietary omega-6 and omega-3 fats, in part, for the high occurrence of prostate cancer.

Recent data show that two key enzymes are increased in prostate tumor tissues, compared to normal tissues.   One of these enzymes is 15-lipoxygenase-1 (15-LOX-1), which prefers linoleic acid, rather than arachidonic acid (both of which are omega-6 polyunsaturated fatty acids.)  The compound created from the union of linoleic acid and 15-LOX-1, contributes to the initiation and development of prostate cancer.

The other enzyme that increases in prostate cancer is COX-2, which acts on arachidonic acid to create PGE-2, which is also implicated in prostate cancer (and other cancers as well, see China Study Shows Dietary Arachidonic Acid Ups Risk for Colorectal Cancer.)
A recent study, demonstrated that prostate cancer cell growth was inhibited, with the combination of DHA and celecoxib (a medication which is a specific COX-2 inhibitor). 

Enter the EPA factor. When the above two enzymes (5-LOX-1 and COX-2), joins with  EPA, it creates anti-inflammatory and anti-tumorogenic compounds. Taken together, there is a double beneficial effect with increased dietary EPA:
  • Increases anti-tumorogenic compounds
  • Decreases the availability of these enzymes to make tumor promoting compounds from omega-6 fat.
Therefore the researchers theorized that prostate tumor growth can be modulated by "dietarily targeting" the 5-LOX-1 and COX-2 enzymes

Study: An animal model of prostate cancer was used. The mice were injected with prostate cancer-promoting cells and divided into three-isocaloric diets: the control diet, high linoleic acid (omega-6) diet and high omega-3 diet.  (Note, because of cost constraints, the researchers used the omega-3 fatty acid, stearidonic acid, which is the precursor to EPA.)

This was a 28-week dietary study, with a crossover-design at week 23.  At week 23, the high omega-6 diet group was switched over to the high omega-3 diet, and visa versa, the omega-3 fed mice were crossed-over to the omega-6 diet. At week 28 tumors were evaluated for growth, fatty acids, enzyme activities, apoptosis and proliferation

Results: Tumors from the high omega-6 diet group had the most rapid growth.  Yet, when this omega-6 fed group was switched to the omega-3 diet, there was a dramatic decrease in tumor growth. When the omega-3 diet group was switched to the omega-6 diet, the tumors grew more aggressively. 

The omega-6 and omega-3 fatty acid composition of red blood cells and tumor cells,
reflected the diet, and modulated accordingly.  The tumors from the high omega-6 group, had a higher ratio of omega-6:omega-3 fat, nearly 7-fold, compared to the control group.  Similarly, the tumors from the omega-3 fed group, had a 4-fold decrease in the ratio, compared to the control.

Conclusion: Dietary omega-6 and omega-3 fatty acids, effects cell composition, which in turn, influence the activities of enzymes, 15-LO-1 and COX, which effect prostate cancer growth.  When EPA competes
with arachidonic and linoleic acid, for COX and 15-LO-1 enzymes, respectively, it slows prostate cancer growth by creating tumor inhibiting compounds.

Quote: "Importantly, these results further corroborate that SDA (and EPA) does not inhibit either 15-LO-1 or COX, and tumor growth reflects the substrate competition of omega-3 and omega-6 fatty acids."

Link to Full Text Study:
Kelavkar U et al. Prostate tumor growth can be modulated by dietarily targeting the 15-lipoxygenase-1 and cyclooxygenase-2 enzymes.
Neoplasia (2009):11(7):692-699.