Fisking: "Healthy Foods High in Omega-6"

"Fisking:" The word is derived from articles written by Robert Fisk that were easily refuted, and refers to a point-by-point debunking of lies and/or idiocies."*

“Omega-6 fatty acids are essential nutrients for a healthy heart. These heart-healthy fats are found in many foods, particularly vegetable oils, seeds, and nuts. Our body can’t make omega-6s, so we must get them from our diet.—But most of us get more than enough” (Contributors, 2022).

Um, wait. “More than enough,” means too much. How much is too much, and if it’s possible to get too much, is that a problem?

It’s often noted that medical doctors receive essentially no training in nutrition. This is doubly-true for topics involving omega-6 fats, where much of their training is the inverse of the truth. So this notice is worrying:

And sure enough…

“Researchers have questioned whether high omega-6 intake can be too much of a good thing. Studies show our bodies convert linolenic acid (LA) — the most common form of omega-6 — into a compound that can promote inflammation and blood vessel tightening.

Well, they start off strong. It’s “linoleic”, not “linolenic”, which is a different fat, an omega-3 fat.

The effect described sounds like that of thromboxane, which is made from omega-6 fats…

“But recent research indicates this effect is minimal, more likely associated with a diet low in omega-3s — the other group of essential fatty acids we get from foods like fish. Most of us get 14 to 25 times more omega-6 fatty acids than omega-3s.”

This is a misdirection. Omega-6 blocks the beneficial effects of omega-3, and the most effective way to increase omega-3 in your body is to reduce omega-6 first.

“Put another way, only 2 ways are known to increase circulating DHA status in humans: 1) consume (preformed) DHA, or 2) lower dietary LA” (Kothapalli et al., 2020).

The title of this paper says it all: “Dietary Omega-6 Fatty Acid Lowering Increases Bioavailability of Omega-3 Polyunsaturated Fatty Acids in Human Plasma Lipid Pools” (Taha et al., 2014), and of course the other way to interpret that would be, “Dietary Omega-6 Fatty Acid Excess Lowers Bioavailability of of Omega-3 Polyunsaturated Fatty Acids in Human Plasma Lipid Pools.”

In contravention to the research, and to their own comment that we get “more than enough”, they continue:

“That doesn’t mean you must cut back on omega-6s, but balancing them better with omega-3s brings the best health benefits.”

It would take handfuls of omega-3 pills per day to make up for a high omega-6 consumption, and even then you wouldn’t be able to make up for the deficit. And what evidence do they have for “best health benefits”? Nothing is cited.

“Why You Need Omega-6s: Omega-6 fatty acids support proper cell function throughout the body. While they’re available in supplement form, most of us get more than enough from our diets. Experts advise you obtain 5-10% of your daily calories from omega-6 fats, or between 11 and 22 grams on average.”

There they go again. “More than enough…” They now tell us that 10% is enough, although they don’t explain why. In fact, there is a reason.

“An upper boundary for linoleic acid is set at 10 percent of energy for three reasons: (1) individual dietary intakes in the North American population rarely exceed 10 percent of energy, (2) epidemiological evidence for the safety of intakes greater than 10 percent of energy are generally lacking, and (3) high intakes of linoleic acid create a pro-oxidant state that may predispose to several chronic diseases, such as [coronary heart disease] and cancer. Therefore, an [acceptable macronutrient distribution range] of 5 to 10 percent of energy is estimated for n-6 polyunsaturated fatty acids (linoleic acid)” (Institute of Medicine, 2005).

The Institute of Medicine** is the body that the Dietary Guidelines uses to justify their recommendations. It’s the definitive medical standard board for diet and nutrition.

But you’ll note what’s missing here: there’s no research into what is the optimal level. They just note that Americans mostly eat less than 10%, so use that number. They further note that eating in excess might contribute to heart disease and cancer.

When they wrote that heart disease and cancer had already become the #1 and #2 killers of Americans after a multi-decade increase in linoleic acid consumption.

Maybe less would be better?

Additionally, there’s no reason to eat even 5% of LA per day, as the requirement for omega-6 fats is about 1%, at most, and less is sufficient if adequate omega-3 is eaten (de Meijer et al., 2010). Similarly, there’s no reason to eat seed oils for omega-6, as a whole-food diet will provide sufficient omega-6 fats for optimal health.

There’s never been a recorded case of a deficiency of omega-6 fats in humans outside of a synthetic, ultra-processed diet.

Then they continue into the alleged health benefits.

“Studies show a link between higher linoleic acid intake—the most common omega-6—and reduced rates of heart attacks and other heart diseases.”

“Link” is a weasel-word. It sounds like the link in a chain of cause-and-effect. Something you can rely on to produce a given result. How it’s used here, and commonly, is in place of “association”, which is the “correlation” of “Correlation is not causation.” So they’re trying to make you think the evidence is stronger than it is. Correlations can be useful guides to causation, but for medical purposes they’re usually not enough, unless they’re super strong, as in smoking and lung cancer. “Links” must be confirmed by trials, the trials provide the best evidence.

And once you have trials, the “links” don’t carry much weight.

This sentence is misleading in two further regards. The first, and most obvious, is that they only mention “rates” of heart disease. Any assessment of risk needs to start with all-cause mortality. If a treatment reduces the rate of heart disease, but increases death from cancer, would you be interested in that treatment? Probably not, but this is what happened in one trial of treating heart disease with mostly omega-6 fats (Dayton et al., 1969).

The second is that the better evidence, the trials, shows that both heart disease mortality AND all-cause mortality increase when omega-6 fats are provided as a treatment for CVD (Ramsden et al., 2016).

“Some research shows omega-6s may lower cholesterol, keeping your blood vessels clear from build-up that can cause clots and heart problems.”

Yes, Ramsden at al, in their meta-analysis in 2016 found that omega-6 fats lower “cholesterol”, which is consistent with many other studies.

However, in all three studies they examined where omega-6 was prescribed to protect from heart disease, this lowering of cholesterol was accompanied by higher mortality. In the largest, most-rigorous study they found that:

“…a 30 mg/dL (0.78 mmol/L) decrease in serum cholesterol was associated with 22% higher risk of death from any cause…”

Seems like a factor worth considering when prescribing a treatment!

Foods With Omega-6s: Many foods have omega-6 fatty acids, including most processed foods made with vegetable oils, like packaged snacks, frozen pizza, and fast food. These foods' abundance in the average diet contributes to omega-6 and omega-3 imbalances for many of us.

Get that? Processed foods have too much omega-6, because they contain seed oils (“vegetable oils”). They’re correct about this!

In fact, one could define what are known as ultra-processed foods by the inclusion of seed oils in the ingredient list. But then they claim:

Processed foods generally have high levels of saturated and trans fats. So while omega-6s are essential to good health, the source matters. Limit your intake of processed foods and try these more nutritious omega-6-rich alternatives:

In fact, government and industry have been reformulating processed foods for decades to remove saturated and trans fats. They’ve replaced them with seed oils. So most processed foods do not have “high levels of saturated” fats, as we’ve spent a lot of money removing the saturated fats.

“Much of the progress towards meeting the [Dietary Guidelines] has been through decreasing saturated fat, trans fat, refined grains and/or sodium in ways that are not obvious to the consumer” (Rowe et al., 2011)

Saturated fat is not the problem with processed food!

1. Safflower Oil: Safflower oil is a common cooking oil with 12.7 grams of omega-6s per tablespoon. It also contains omega-9s like oleic acid, which can help maintain good blood sugar levels and has anti-inflammatory properties.

So here they go, after telling us that the problem with processed foods is that they have too much omega-6, they suggest we eat an ultra-processed food that is super-high in omega-6.

That is a sure-fire way to get “too much” omega-6!

Incidentally, omega-9 fats only have anti-inflammatory properties when they are replacing omega-6 fats (Reaven et al., 1993; van der Valk et al., 2016).

Unfortunately, this is par for the course for medical advice on food.

As always, the dose makes the poison. Omega-6 fats including linoleic acid are a normal part of our diet, and are found in many, if not all, natural, healthy foods.

But it’s clear that too much omega-6 coupled with not enough omega-3 is a major health problem in the United States and the world.

If would be better if medical professionals addressed this fact forthrightly, instead of misrepresenting the problem in a confused and incoherent manner as done here.

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Thanks to Robert Stoll:

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*From: https://www.urbandictionary.com/define.php?term=Fisking

** The Institute of Medicine is now called the National Academy of Medicine.

Contributors, W. E. (2022, November 23). Healthy Foods High in Omega-6 [Medical Information]. WebMD. https://www.webmd.com/diet/foods-high-in-omega-6

Dayton, S., Pearce, M. L., Hashimoto, S., Dixon, W. J., & Tomiyasu, U. (1969). A Controlled Clinical Trial of a Diet High in Unsaturated Fat in Preventing Complications of Atherosclerosis. Circulation, 40(1s2), II–1. https://doi.org/10.1161/01.CIR.40.1S2.II-1

de Meijer, V. E., Le, H. D., Meisel, J. A., Gura, K. M., & Puder, M. (2010). Parenteral Fish Oil as Monotherapy Prevents Essential Fatty Acid Deficiency in Parenteral Nutrition Dependent Patients. Journal of Pediatric Gastroenterology and Nutrition, 50(2), 212–218. https://doi.org/10.1097/MPG.0b013e3181bbf51e

Institute of Medicine. (2005). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. https://doi.org/10.17226/10490

Kothapalli, K. S. D., Park, H. G., & Brenna, J. T. (2020). Polyunsaturated Fatty Acid Biosynthesis Pathway and Genetics. Implications for Interindividual Variability in Prothrombotic, Inflammatory Conditions Such as Covid-19. Prostaglandins, Leukotrienes and Essential Fatty Acids, 162, 102183. https://doi.org/10.1016/j.plefa.2020.102183

Ramsden, C. E., Zamora, D., Majchrzak-Hong, S., Faurot, K. R., Broste, S. K., Frantz, R. P., Davis, J. M., Ringel, A., Suchindran, C. M., & Hibbeln, J. R. (2016). Re-evaluation of the traditional diet-heart hypothesis: Analysis of recovered data from Minnesota Coronary Experiment (1968-73). BMJ, 353. https://doi.org/10.1136/bmj.i1246

Reaven, P., Parthasarathy, S., Grasse, B. J., Miller, E., Steinberg, D., & Witztum, J. L. (1993). Effects of Oleate-Rich and Linoleate-Rich Diets on the Susceptibility of Low Density Lipoprotein to Oxidative Modification in Mildly Hypercholesterolemic Subjects. Journal of Clinical Investigation, 91(2), 668–676.

Rowe, S., Alexander, N., Almeida, N., Black, R., Burns, R., Bush, L., Crawford, P., Keim, N., Kris-Etherton, P., & Weaver, C. (2011). Food Science Challenge: Translating the Dietary Guidelines for Americans to Bring About Real Behavior Change. Journal of Food Science, 76(1), R29–R37. https://doi.org/10.1111/j.1750-3841.2010.01973.x

Taha, A. Y., Cheon, Y., Faurot, K. F., MacIntosh, B., Majchrzak-Hong, S. F., Mann, J. D., Hibbeln, J. R., Ringel, A., & Ramsden, C. E. (2014). Dietary Omega-6 Fatty Acid Lowering Increases Bioavailability of Omega-3 Polyunsaturated Fatty Acids in Human Plasma Lipid Pools. Prostaglandins, Leukotrienes, and Essential Fatty Acids, 90(5), 151–157. https://doi.org/10.1016/j.plefa.2014.02.003

van der Valk, F. M., Bekkering, S., Kroon, J., Yeang, C., Van den Bossche, J., van Buul Jaap D., Ravandi Amir, Nederveen Aart J., Verberne Hein J., Scipione Corey, Nieuwdorp Max, Joosten Leo A.B., Netea Mihai G., Koschinsky Marlys L., Witztum Joseph L., Tsimikas Sotirios, Riksen Niels P., & Stroes Erik S.G. (2016). Oxidized Phospholipids on Lipoprotein(a) Elicit Arterial Wall Inflammation and an Inflammatory Monocyte Response in Humans. Circulation, 134(8), 611–624. https://doi.org/10.1161/CIRCULATIONAHA.116.020838