# Essential fatty acids (EFA)

Category: Foods & Substances

Also known as: essential fatty acids, Essential fatty acids, EFA, efa

EFA are, according to the textbooks, linoleic acid and linolenic acid, and they are supposed to have the status of "vitamins," which must be taken in the diet to make life possible. However, we are able to synthesize our own unsaturated fats when we don't eat the "EFA," so they…

11 passages · 1 author · 2006–2022 · Most-cited: [Ray Peat](https://bioenergeticoracle.com/md/voices/ray-peat/index.md)

Canonical page: https://bioenergeticoracle.com/concepts/essential-fatty-acids-efa

## Synthesis

**Essential fatty acids (EFA)** are, according to mainstream textbooks, linoleic acid and linolenic acid, but Ray Peat argued that the term is a misnomer because humans can synthesize their own unsaturated fats when dietary EFA are absent. [Source 1, 7] Peat traced the doctrine of essentiality to flawed 1929 experiments by George and Mildred Burr, who claimed these fats prevented a specific disease in rats while ignoring contemporary studies showing that fat-free diets eliminated almost all cancers and slowed aging. [Source 3] He noted that the Burrs' "EFA deficiency disease" was later cured by **vitamin B6** without adding any fats, demonstrating that the original syndrome was a B6 deficiency, not a lack of polyunsaturated fats. [Source 3] Peat maintained that he had never seen convincing evidence for essentiality, pointing out that human cells can grow and divide indefinitely in *completely fat-free culture media*, proving that dietary PUFA are not required for membrane synthesis. [Source 10, 11]

Peat contended that the EFA doctrine was resurrected in the 1950s by the seed oil industry after petroleum displaced soy oil from its industrial uses in paints and plastics. [Source 8] He described this as a "gigantic industrial food fraud," where the observation that PUFA fattened pigs economically was repurposed into a human health claim, bolstered by the argument that PUFA lower cholesterol. [Source 8] The body of evidence Peat assembled indicates that the so-called essential fatty acids are not merely unnecessary but actively harmful, amplifying nearly all kinds of injury and stress. [Source 5] Their oxidative breakdown products, such as **acrolein** and other aldehydes, combine with proteins to produce immunogenic substances, and the so-called *advanced glycation end products* blamed on glucose are mostly derived from the peroxidation of PUFA, which damages proteins roughly 23 times faster than simple sugars. [Source 2]

The toxic effects of EFA extend to the brain, immune system, and hormonal regulation. Pregnant mice fed unsaturated seed oil produced offspring with *smaller brains and inferior intelligence* compared to those fed coconut oil, and radioactively labeled soy oil fed to nursing rats was massively incorporated into brain cells, causing visible structural changes. [Source 4] Peat highlighted that the thymus gland is particularly vulnerable, with Soviet researchers comparing the effects of PUFA on the thymus to those of **radiation**, leading to immunodeficiency with prolonged high intake. [Source 5, 6] Furthermore, EFA and their products act synergistically with estrogen and serotonin to create cellular excitation, interfere with stable cellular water structure, and promote wakefulness; babies of mothers with higher serum DHA were more wakeful on their second day of life. [Source 2, 6] In contrast, saturated fats and progesterone stabilize cell water and oppose these excitatory effects. [Source 6]

Animals fed diets deficient in EFA exhibit remarkable properties: they consume oxygen and calories at a very high rate, possess unusually tough and stable mitochondria, resist immunological rejection of transplanted tissues, and are very hard to kill by trauma and a wide variety of toxins. [Source 9] Peat suggested that the optimal dietary level of EFA might be close to zero if other dietary factors were optimized, noting that the fat of wild animals can be highly unsaturated depending on their diet, and that modern "animal fats" from grain-fed livestock are themselves rich in vegetable oils. [Source 7] The long-chain omega-3 fats found in fish oil, while less immediately toxic than seed oils, still promoted a 10-fold increase in the number of tumor metastases and a 1,000-fold increase in their size in experimental models. [Source 6] Peat observed that the body, when not flooded with dietary PUFA, synthesizes **Mead acid**, an omega-9 polyunsaturated fat with a saturated tail that is relatively resistant to oxidation, and that the placenta actively filters out environmental unsaturated fats to protect the developing fetus. [Source 11]

## People also ask

### Why did Ray Peat consider "essential fatty acids" a misnomer?

Peat argued that humans can synthesize their own unsaturated fats when dietary EFA are absent, and he noted that human cells grow indefinitely in completely fat-free culture media, proving dietary PUFA are not required for membrane synthesis.

### What did Peat identify as the original cause of the Burrs' "EFA deficiency" disease?

Peat pointed out that the syndrome the Burrs attributed to a lack of polyunsaturated fats was later cured by vitamin B6 without adding any fats, demonstrating it was actually a B6 deficiency rather than an EFA deficiency.

### How do EFA-deficient animals differ from those fed unsaturated fats?

The corpus describes EFA-deficient animals as having a very high metabolic rate, unusually tough and stable mitochondria, resistance to immunological rejection of transplants, and a strong resistance to trauma and a wide variety of toxins.

## Related concepts

- [PUFA (polyunsaturated fatty acids)](https://bioenergeticoracle.com/md/concepts/pufa-polyunsaturated-fatty-acids/index.md)
- [Pregnenolone](https://bioenergeticoracle.com/md/concepts/pregnenolone/index.md)
- [Thyroid Stimulating Hormone (TSH)](https://bioenergeticoracle.com/md/concepts/thyroid-stimulating-hormone-tsh/index.md)
- [Unsaturated oils](https://bioenergeticoracle.com/md/concepts/unsaturated-oils/index.md)
- [Adrenaline](https://bioenergeticoracle.com/md/concepts/adrenaline/index.md)
- [Age Pigment (Lipofuscin)](https://bioenergeticoracle.com/md/concepts/age-pigment-lipofuscin/index.md)

## Cited passages

Passage numbers match the `[Source N]` markers in the synthesis above.

### Source 1 — Glossary

Ray Peat · Glossary

> Essential fatty acids (EFA)
>
> EFA are, according to the textbooks, linoleic acid and linolenic acid, and they are supposed to have the status of "vitamins," which must be taken in the diet to make life possible. However, we are able to synthesize our own unsaturated fats when we don't eat the "EFA," so they are not "essential." The term thus appears to be a misnomer.

### Source 2 — Unsaturated fatty acids: Nutritionally essential, or toxic?

Ray Peat · Article · 2008 · https://raypeat.com/articles/articles/unsaturatedfats.shtml

> Inflammation contributes to the decreasing ability to use oxygen, and the slowed renewal of proteins combined with lower ability to produce energy impair the organism's ability to control peroxidative damage and inflammation. The fragments of deteriorating PUFA combine with proteins and other cell materials, producing immunogenic substances. The so-called "advanced glycation end products," that have been blamed on glucose excess, are mostly derived from the peroxidation of the "essential fatty acids." The name, “glycation,” indicates the addition of sugar groups to proteins, such as occurs in diabetes and old age, but when tested in a controlled experiment, lipid peroxidation of polyunsaturated fatty acids produces the protein damage about 23 times faster than the simple sugars do (Fu, et al., 1996).
>
> Several autoimmune disease models in animals (involving the eye, kidney, and pancreas) have been prevented by a deficiency of the EFA (Schreiner, et al., 1989, Bazan, et al., 1990, Benhamou, et al., 1995). Besides causing a general slowing of metabolism, aging and toxic PUFA have specific actions on the detoxifying system. The enzymes that help to detoxify PUFA and estrogen and serotonin are inhibited by both PUFA and estrogen. All systems, including blood vessels and the intestine, are made leaky by estrogen and the PUFA and their products. A reduced ability to regulate the excitatory amino acids, resulting from PUFA toxins, tends to produce excitotoxicity, damaging nerves (Ou, et al., 2002).
>
> Although the interplay of the various types of nerve is very complex, a variety of experiments suggest that the PUFA are acting directly on serotonergic nerves, rather than just increasing the conversion of tryptophan to serotonin. For example, a deficiency of the so-called essential fatty acids, EFA, makes animals more sensitive to some anesthetics, and more resistant to others. It makes them resistant to the anesthetics that act by promoting the actions of serotonin, but it prolongs the effects of those that don't act through serotonin, and these are the anesthetics such as xenon and nitrous oxide, that apparently act by stabilizing the structure of water, as described by Linus Pauling.

### Source 3 — Life Supporting Substances Its Rain Making Time 2011 07 04

Ray Peat · Interview · Jul 4, 2011 · http://l-i-g-h-t.com/files/rarinmaking-time-life-supporting-substances.mp4

> **Ray Peat:** The way a lot of these people are reasoning is to identify the fish oils, DHA and EPA, as essential fatty acids, or the omega-3 oils as essential fatty acids, and then say, "Since they are essential nutrients, they can't be toxic." Some of the articles on my website deal first with that issue of essentiality, and show that the basic studies that are still being cited were done in 1929 by George Burr and his wife. And at the time they published their results, they neglected to mention (several very well known articles were published in the same journal they published in) studies showing that those very fats that the Burrs were claiming to be essential nutrients were actually life-shortening ingredients in the diet. One study, two years before they published, showed that a fat-free diet eliminated almost all cancers in their experimental animals, as well as slowing the aging process. But they just ignored the contrary evidence and pronounced that linoleic and linolenic acids were essential to prevent a certain disease in rats (scaly tail disease, bloody urine, and such). It was about 16-17 years later that Roger Williams’ Lab in Texas (they had been studying the B-vitamins) recognized the Burrs' rat disease as a vitamin B6 deficiency disease. And vitamin B6 wasn't even known at the time the Burrs where giving their rats the specialized diet. So, Roger Williams Lab gave exactly the same diet the Burrs had used, and created the deficiency disease – “essential fatty acid deficiency symptoms” - and then, without adding any fats at all, they gave the rats vitamin B6 and cured the Burrs' deficiency disease.

### Source 4 — Oils in Context

Ray Peat · Article · 2006 · https://raypeat.com/articles/nutrition/oils-in-context.shtml

> Some of their graphs make the point very clearly: [52} This suggests that the optimal EFA intake might be 0.5% or less. Butter and coconut oil contain significant amounts of the short and medium-chain saturated fatty acids, which are very easily metabolized, [60] inhibit the release of histamine, [39] promote differentiation of cancer cells, [61] tend to counteract the stress-induced proteins, [62] decrease the expression of prolactin receptors, and promote the expression of the T3 (thyroid) receptor. [63] (A defect of the thyroid receptor molecule has been identified as an "oncogene," responsible for some cancers, as has a defect in the progesterone receptor.) Besides inhibiting the thyroid gland, the unsaturated fats impair intercellular communication,[64] suppress several immune functions that relate to cancer, and are present at high concentrations in cancer cells, where their antiproteolytic action would be expected to interfere with the proteolytic enzymes and to shift the equilibrium toward growth. In the free fatty acid form, the unsaturated fats are toxic to the mitochondria, but cancer cells are famous for their compensatory glycolysis.
>
> By using lethargic connective tissue cells known to have a very low propensity to take up unsaturated fats [65] as controls in comparison with, e.g., breast cancer cells, with a high affinity for fats, it is possible to show a "selective" toxicity of oils for cancer cells. However, an in vivo test of an alph-linolenic acid ester showed it to have a stimulating effect on breast cancer. [66] Given a choice, skin fibroblasts demonstrate a very specific preference for oleic acid, over a polyunsaturated fat. [67]
>
> Even if unsaturated fats were (contrary to the best evidence) selectively toxic for cancer cells, their use in cancer chemotherapy would have to deal with the issues of their tendency to cause pulmonary embolism, their suppression of immunity including factors specifically involved in cancer resistance, and their carcinogenicity.
>
> Brain Damage And Lipid Peroxidation: When pregnant mice were fed either coconut oil or unsaturated seed oil, the mice that got coconut oil had babies with normal brains and intelligence, but the mice exposed to the unsaturated oil had smaller brains, and had inferior intelligence.

### Source 5 — Unsaturated fatty acids: Nutritionally essential, or toxic?

Ray Peat · Article · 2008 · https://raypeat.com/articles/articles/unsaturatedfats.shtml

> Alzheimer's disease, retinal degeneration, cataracts, and liver cirrhosis all involve reactions of oxidized PUFA with proteins. Saturated fats help to heal alcoholic liver cirrhosis. The lesions of atherosclerosis and cataracts contain some of the same oxidized lipids as the age pigment itself. When large deposits of age pigment become visible, it's probably because the general reduction of metabolism and protein synthesis has interfered with the normal processes for removing debris. The age pigment contributes to degeneration by wasting energy and oxygen, weakening the antioxidation, antiglycation, and other defensive systems.
>
> The EFA amplify nearly all kinds of injury and stress, and the results of many recent publications make it look as though serotonin interacts harmfully with the EFA in most of these situations. The specific balance of polyunsaturated fatty acids, and their various breakdown products, from carbon monoxide, glyoxal, and acrolein, to the larger aldehydes and radicals, and the stress-induced substances such as serotonin, histamine, estrogens, can produce an immense variety of biological problems. When the various claims of an EFA "deficiency disease" or syndrome or symptom are examined, their inconsistency over the years makes skepticism seem increasingly justified. The Burrs' publications were typical of others, in failing to describe and account for the evidence that contradicted their claims.
>
> Claiming that certain fatty acids are essential, a scientific approach would require showing what was wrong with the experiments that showed that they were not essential, and especially, those that showed that they were positively harmful. In this culture that repeatedly makes such claims of essentiality, the growing number of reports of biological superiority of "deficient" animals suggests that nutritional research may be near the point at which it can resume the line of study begun by Northrup, Osborne, Mendel, Drummond, Bernstein, Elias, and others, that was interrupted for 60 years by industrial interests that promoted antiscientific opinions.
>
> For example, in 1914 F.P. Rous showed that limiting food intake reduced the incidence of cancer, and then in 1915 and 1917, Osborne and Mendel showed that food restriction extended the fertility and longevity of female rats.

### Source 6 — Unsaturated fatty acids: Nutritionally essential, or toxic?

Ray Peat · Article · 2008 · https://raypeat.com/articles/articles/unsaturatedfats.shtml

> Progesterone and the saturated fats seem to act partly through the stabilizing of cell water, and estrogen and the PUFA have opposing effects, creating cellular excitation while interfering with the stable cellular water structure. Serotonin interferes with slow wave sleep, and promotes cortisol, both of which can be harmful to brain cells. (Hypothyroidism is one of the causes of a decrease in slow wave sleep.) Babies whose mothers' serum contained more DHA were more wakeful on their second day of life, than the babies of low-DHA mothers. The amide of oleic acid is a sleep promoter, with apparent antiserotonin activity (Yang, et al., 2003), and since oleic acid tends to be displaced by diets high in PUFA, this suggests another way in which the highly unsaturated fatty acids could promote serotonin's effects.
>
> People who don't have a normal amount of slow wave sleep are likely to have slow reaction times when they are awake, and quickness of reactions is a good indicator of general intelligence. Manufacturers of baby formulas are claiming that the highly unsaturated fatty acids accelerate brain development, but they neglect to mention studies that show either no effect, or retardation of development. In some of the tests that are used to measure infant development, a generalized state of arousal or anxiety could be interpreted as "more mature." In one experiment, animals that received less than 0.32% of their calories as EFA grew slightly less than rats on a standard diet, but their brains were as large as those of normal rats (Bruckner, et al., 1984). That is, their brain to body ratio was a little larger than normal, which is a typical feature of individuals with a higher metabolic rate. That result is very different from the claims of the baby food industry, that the brain is the organ most easily damaged by a PUFA deficiency.
>
> One of the standard signs of toxicity is the enlargement of the spleen and liver, and that effect is produced by larger amounts of the EFA. The weight of the thymus is reduced by PUFA in the diet (Guimarães, et al., 1990). Thymus cells tend to be easily killed by a combination of stress and EFA, and bone marrow cells, though less sensitive than thymic cells, are damaged by lipid peroxidation of the PUFA.

### Source 7 — Oils in Context

Ray Peat · Article · 2006 · https://raypeat.com/articles/nutrition/oils-in-context.shtml

> Some insects that have been studied have been found not to require the essential fatty acids. [14]
>
> - According to reviewers, hogs and humans have not been shown to require the "essential" fatty acids. [15] In vitro studies indicate that they are not required for human diploid cells to continue dividing in culture. [16] According to Guarnieri, [17] EFA-deficient animals don't die from their deficiency. The early studies showing "essentiality" of unsaturated fats, by producing skin problems and an increased metabolic rate, have been criticized [18] in the light of better nutritional information, e.g., pointing out that the diets might have been deficient in vitamin B6 and/or biotin. The similar skin condition produced by vitamin B6 deficiency was found to be improved by adding unsaturated fats to the diet. A fat-free liver extract cured the "EFA deficiency." I think it would be reasonable to investigate the question of the increased metabolic rate produced by a diet lacking unsaturated fats (which inhibit both thyroid function and protein metabolism) in relation to the biological changes that have been observed. Since diets rich in protein are known to increase the requirement for vitamin B6 [19] (which is a co-factor of transaminases, for example), the increased rate of energy production and improved digestibility of dietary protein on a diet lacking unsaturated fats would certainly make it reasonable to provide the experimental animals with increased amount of other nutrients. With increasing knowledge, the old experiments indicating the "essentiality" of certain oils have lost their ability to convince, and they haven't been replaced by new and meaningful demonstrations. In the present state of knowledge, I don't think it would be unreasonable to suggest that the optional dietary level of the "essential fatty acids" might be close to zero, if other dietary factors were also optimized. The practical question, though, has to do with the dietary choices that can be made at the present time.
>
> - If we followed Linus Pauling's reasoning in determining optimal vitamin C intake, this study of the linoleic acid content of the tissues of an animal which can synthesize it would suggest that we are eating about 100 times more "EFA" than we should. In evaluating dietary fat, it is too often forgotten that the animals' diet (and other factors, including temperature) affect the degree of saturation of fats in its tissues, or its milk, or eggs.

### Source 8 — Blood Tests, Hormones, Protein Intake & Ray's Carb List

Ray Peat · Interview · Jun 16, 2022 · https://www.youtube.com/watch?v=495CtgExBXE

> [42:32] Okay perfect. Another listener they didn't give their name they said you mentioned in response to an explanation on the dangers of EFA that although it was counterintuitive it makes much sense to you. I'm struggling to understand how it makes sense could you please expound on your understanding as a person is struggling with Hashimoto's and having recently recovered from colon cancer. I'm wondering how diet compare how your form of eating compares with the Mediterranean diet which is supposed to be one of the best. Could you please elaborate on EFA? Oh it's Gracie's gift that's who asked that. What does that stand for? Essential fatty acids the dangers of maybe I guess she's maybe thinking of like fish oil like a plant saturated fish oil. No there are some very good books that go into a matter of more than a thousand references [43:38] on the question of essential fatty acids and fish oils. The name of one that occurs to me is fishy business. Okay I'll put that in the net. And my website has I think three or four very basic explanations for why the doctrine of such a thing as an essential fatty acid was resurrected. It had been knocked out or demonstrated to be a fallacy in the 1940s. It's just absolutely knocked out nothing scientific left but the seed oil industry was losing their customers. They produced a huge amount of [44:40] soy oil and related polyunsaturated oils to make paints and plastics from. Petroleum displaced that around 1950 and they found that the essential fatty acids created economical fat gain in pigs and other farm animals. So this was promoted that the you know essential fatty acids or PUFA came to be advertised as edible because they would make pigs get fat cheaply that led to promoting them as human health foods. A very ridiculous set of reasoning but it incorporated the idea that [45:43] PUFA lowers cholesterol. Cholesterol causes heart disease therefore PUFA as an essential nutrient should be included in the diet the more the better. Every step of the reasoning was simply an advertisement to get people to fatten themselves on PUFA the way pigs were being fattened. So it's a gigantic industrial food fraud all through the 1950s absolutely no science remaining but penetrating just about everything in industrial society.

### Source 9 — Fats and degeneration

Ray Peat · Article · 2013 · https://raypeat.com/articles/articles/fats-degeneration3.shtml

> Through the 1970s, this sort of information about the harmful effects of the PUFA was being slowly assimilated by the culture, though many dietitians still spoke of "the essential fatty acids, vitamin F." By 1980, it looked as though responsible researchers would see the promotion of cancer, heart disease, mitochondrial damage, hypothyroidism and immunosuppression caused by the polyunsaturated fats as their most important feature, and would see that there had never been a basis for believing that they were essential nutrients.
>
> But then, without acknowledging that there had been a problem with the doctrine of essentiality, fat researchers just started changing the subject, shifting the public discourse to safer, more profitable topics.
>
> The fats that had been called essential, but that had so many toxic effects, were no longer emphasized, and the failed idea of "essentiality" was shifted to different categories of polyunsaturated fats.
>
> The addition of the long chain highly unsaturated fats to baby food formulas was recently approved, on the basis of their supposed "essentiality for brain development." One of the newer arguments for the essentiality of the PUFA is that "they are needed for making cell membranes." But human cells can grow and divide in artificial culture solutions which contain none of the polyunsaturated fats, and no one has claimed that they are growing "without membranes." The long chain fats found in fish and some algae don't interfere with animal enzymes as strongly as the seed oils do, and so by comparison, they aren't so harmful. They are also so unstable that relatively little of them is stored in the tissues. (And when they are used as food additives, it's necessary to use antioxidants to keep them from becoming smelly and acutely toxic.) When meat is grilled at a high temperature, the normally spaced double bonds in PUFA migrate towards each other, becoming more stable, so that linoleic acid is turned into "conjugated linoleic acid." This analog of the "essential" linoleic acid competes against the linoleic acid in tissues, and protects against cancer, atherosclerosis, inflammation and other effects of the normal PUFA.
>
> Presumably, anything which interferes with the essential fatty acids is protective, when the organism contains dangerous amounts of PUFA.
>
> Even the trans-isomers of the unsaturated fatty acids (found in butterfat, and convertible into conjugated linoleic acid) can be protective against cancer.

### Source 10 — Life Supporting Substances Its Rain Making Time 2011 07 04

Ray Peat · Interview · Jul 4, 2011 · http://l-i-g-h-t.com/files/rarinmaking-time-life-supporting-substances.mp4

> **Ray Peat:** I have been asking people for about 40 years now, what the evidence is for the essentiality of any of these fats. And those very odd few studies are the only things anyone has ever mentioned to me.
>
> **Kim Greenhouse:** Essential fatty acids are unsaturated oils, correct?
>
> **Ray Peat:** That's what they say: but I have never seen any evidence that convinced me that they had proved that they were essential. For example, they say you need them to make membranes; but you can grow cells in a culture dish in a completely fat-free mixture. So the cells divide and act like normal cells, but there is no fat being added. So, it can't be essential for making membranes.
>
> **Kim Greenhouse:** So obviously it was miscategorized, or misnamed, or misrepresented?
>
> **Ray Peat:** Well, [concerning] the Burrs, I think it was basic incompetence, that they didn't deal with the contrary evidence. They just simply ignored several very good and important studies and announced that their study had defined the essentiality of a nutrient, which other studies had denied and presented very good contradictory evidence. So when you look at the particular studies that are used as a basis for saying that they are essential, those studies definitely don't do it. So, I'm still waiting for someone to show me evidence that these fats are essential.

### Source 11 — Ask the Herb Doctor: Lipofuscin

Ray Peat · Interview · Aug 19, 2022

> ## The Myth of Essential Fatty Acids (PUFA)
>
> **Andrew Murray:** I want to expand on your work regarding lipofuscin. We’ve mentioned it in relation to polyunsaturated fatty acids (PUFA). Public awareness has exploded recently with publications stating that PUFAs are not safe, contrary to the thinking of the last three decades. Can we start by going over some basics regarding these so-called "essential fatty acids"? If you look online, it implies they are only available from the diet. Is that correct?
>
> **Ray Peat:** No. Some very simple experiments make that really clear, but that clarity has hardly penetrated the beliefs about the facts over the last 80 years because industry has found a motive in claiming they are essential. The evidence against it is clear. For example, you can grow human cells in culture. If you are growing huge masses of cells, you know exactly what they are being fed. You can feed them a diet absolutely excluding unsaturated fatty acids. They multiply enormously on a diet of no environmental unsaturated fats. Obviously, any unsaturated fat they contain is something they have made themselves. The evidence that we aren't getting environmental linoleic or arachidonic acid and are becoming "deficient" is based on the finding that we make something called Mead acid. Mead acid is an omega-9 series polyunsaturated fat with a long saturated tail—just the opposite of fish oil. The n-3 (omega-3) series has unsaturated groups within three carbons of the tip. The type we make ourselves, the Mead acids, have saturated fats extending down to within nine carbons at the end. That makes them relatively resistant to external contact with oxygen.

_Generated 2026-07-20 from the Bioenergetic Oracle corpus._