In this 2018 article, James DiNicolantonio and James O’Keefe (St. Luke’s Mid America Heart Institute) review the evidence that linoleic acid is a harmful—and possibly causal—driver of heart disease.
Linoleic acid (a polyunsaturated fat) is a major fatty acid in vegetable oils: It makes up over 50 percent of soybean oil, corn oil, sunflower oil, and many similar substances. Since the late 1950s, vegetable-oil consumption (and thus consumption of linoleic acid) has increased dramatically in the U.S., rising from under four percent to eight to 10 percent of our total energy intake.
Multiple pieces of evidence suggest linoleic acid plays a role in heart-disease progression. A major heart-disease model suggests low-density lipoproteins must be oxidized to begin forming plaques (oxidized LDL cannot be recycled by the liver but can be recognized by macrophages, leading to foam-cell development). Linoleic acid is more susceptible to oxidation than other fatty acids and is the most commonly oxidized fatty acid found in LDL; oxidized linoleic acid derivatives are frequently found in plaques, and the amount of these fatty acids found in plaques correlates with disease severity. Additionally, multiple clinical trials—e.g., the Sydney Diet Heart Study (1) and Minnesota Coronary Experiment (2,3)—have shown that replacing saturated fats with polyunsaturated fats generally or linoleic acid specifically increased all-cause and/or coronary mortality.
A diet-heart hypothesis view will suggest linoleic acid is cardioprotective because replacing saturated fat with linoleic acid will reduce total and LDL cholesterol levels (3). However, the evidence regarding oxidation of linoleic acid suggests these markers fail to capture the whole picture, and linoleic acid in fact increases cardiovascular risk directly. This, in turn, suggests the dramatic increase in vegetable-oil consumption in western diets may have contributed to the increase in cardiovascular mortality.
ADDITIONAL READING
- Ramsden CE, Zamora D, Leelarthaepin B, Majchrzak-Hong SF, Faurot KR, Suchindran CM, Ringel A, Davis JM, and Hibbeln JR. Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis. BMJ 346(8707), 2013. Available here.
- O’Connor A. A decades-old study, rediscovered, challenges advice on saturated fat. The New York Times. April 13, 2016. Available here.
- Ramsden CE, Zamora D, Leelarthaepin B, Majchrzak-Hong SF, Faurot KR, Broste SK, Frantz RP, Davis JM, Ringel A, Suchindran CM, Hibbeln JR. Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from Minnesota Coronary Experiment (1968-73). BMJ 353(1246), 2016. Available here.
Comments on Omega-6 Vegetable Oils as a Driver of Coronary Heart Disease: The Oxidized Linoleic Acid Hypothesis
That is why I can't believe we still serve margarine!
Notice a trend in many "healthy" recipes to start with a super lean piece of meat; e.g., skinless chicken breast, and then have to add some form of vegetable oil-based sauce or dressing to make it palatable. I suggest remove the fat swap by starting with a fattier piece of meat such as chicken thigh.
The problem is not the source but the volume of the intake. You dont want to focus O6 but more O3 ! There is no reason to supplement / focus on O6, since the intake is too high anyways compared to O6
I can’t imagine it’s a coincidence that the oils most often used in processed foods - those highest in Linoleic acid - are those from food most subsidized by federal farm policy. More bad policy driving sad health outcomes.
While this may be widely known among the CrossFit community, it is definitely not among the general population, and as such bears repeating. A casual check of food labels throughout the grocery store reveals that inexpensive omega-6 vegetable oils are the food industry's oil of choice.Thank you, CrossFit, for underscoring this important concept.
Totally agree. The USDA Dietary Guidelines which dictate national food policies and programs encourages vegetable oils. In fact, they include strategies to shift from butter to vegetable oils.
https://www.choosemyplate.gov/oils
https://health.gov/dietaryguidelines/2015/guidelines/chapter-2/a-closer-look-at-current-intakes-and-recommended-shifts/
It’s unfortunate that vegetable oils are used so commonly when eating out, or with pre prepared foods. Awareness is essential.
Similar to the question Joe asked, what about Conjugated Linoliec acid (sp?) like that found in cow's milk. I thought CLA was 'cardiac' and 'brain' positive with no known downside. Perhaps Linoleic is different than CLA(?)
Nothing new here. There have been studies since before 2009 saying the same thing. Any cardiologist worth his salt has know this for over a decade.
So I know it said specifically or something along the lines of the omega-6 being more harmful when coming from the vegetable oils but what about the omega-6 intake from farmed salmon?
I will not eat farmed fish, and I'm a little weary of hearing the term "sustainably raised" in reference to farmed fish, as it appears to assert a health benefit.
Omega-6 Vegetable Oils as a Driver of Coronary Heart Disease: The Oxidized Linoleic Acid Hypothesis
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