Source: Volodymyr Melnyk/123RF
So a fatty acid walks into a psychiatrist’s office.
Psychiatrist: What brings you in today?
Fatty Acid: I’m depressed and lonely. Most people completely ignore me and don’t even know I exist. And to make matters worse, prominent public health officials and influential physicians spread rumors about me, saying all I do is cause inflammation and chronic disease. It hurts my feelings.
Psychiatrist: Well, do you cause inflammation?
Fatty Acid: Yes, okay, okay, it’s true, I do cause inflammation, but you gotta understand—it’s complica—
Psychiatrist: I’m sorry for interrupting you. I’d like to try to help you, but before we dig deeper, please fill out this demographics form I need for billing purposes.
Name: Arachidonic Acid (ARA)
Family: Omega-6 polyunsaturated fatty acid (PUFA)
Age: millions of years old
Address: animal cell membranes
- Inflammation promoter
- Brain developer
- Membrane fluidity maintenance engineer
- Muscle repairman
- Brain cell communicator
- Cholesterol metabolizer
- Stomach acid inhibitor
- Uterine contractor
- Coagulation coordinator
- Kidney filtration manager
- HPA axis influencer
- Endocannabinoid synthesizer
- Blood vessel dilator
- Airway diameter controller
- Intestinal motility foreman
- Healing promoter
P: Interesting. You sure you’re not depressed from working too hard? Look at all these jobs. Maybe you need some time off.
ARA: You see what I’m talking about! Nobody appreciates all the things I do for them. Most people have no idea that they can’t live without me.
P: But surely you can understand why people are afraid of you. Right there at the top of your list is inflammation.
ARA: You say that like it’s a bad thing. I can’t believe you went to medical school and don’t realize the importance of inflammation. Inflammation is the critical first step in the body’s response to things like infections and injuries. And if you’d bothered to read all the way to the bottom of the list, you would have noticed that I don’t just promote inflammation—I also promote healing. I’m not just one-dimensional. Peel the onion.
P: I can’t help but notice that you’re only located in animal foods—that’s another justifiable reason why people avoid you like the plague, is it not?
ARA: Look, I know you’re only in your fifties, so you’re not going to believe me, but I’ve been around for millions of years, and I’m telling you it never used to be this way. I used to be popular, valued. I used to be a contender. People used to prize animal foods for being nutritious, now they demonize the very nutrients within them that make them essential to human life. If you think I’m just playing the victim card here, you should know I’m not the only one. Go ask heme iron, or cholesterol, or carnitine—they’ll tell you. It’s crazy-making. Nothing makes sense anymore. [chokes back tears] I’m thinking of leaving this world behind.
P: You don’t mean…
ARA: Yep. The big A. Apoptosis. I’m going to do myself in. Being able to trigger cell death is just another one of my superpowers. I didn’t put it on the list…for obvious reasons.
P: I’m beginning to understand how painful your existence feels. Looking over that list again, it’s clear you have so much to give. People may not like you, but they still need you, right? Are you considered an essential nutrient?
ARA: Public health officials don’t consider me essential, but a growing number of scientists disagree and are advocating on my behalf.
P: Well, there, you see? Not everyone in the world is against you.
ARA: When did I ever say that? Review your notes, doc. I’m not paranoid, I’m depressed. Now can we get back to my real problem?
P: Ok, I’m sorry. Please go on. Why do officials think we don’t need you?
ARA: There is a biochemical pathway in human cells that can turn linoleic acid into arachidonic acid. Linoleic acid is found in plant and animal foods, so it’s easy to obtain regardless of dietary preferences. Nearly a century ago, it was shown that linoleic acid can be used to reverse obvious symptoms of essential fatty acid deficiency (EFAD), a rare disorder caused by fat-free diets, so linoleic acid was crowned as the essential omega-6 fatty acid.
P: This looks like an open-and-shut case in support of linoleic acid as the most important omega-6, but I sense you’d disagree?
ARA: Now you’re catching on. It turns out that this pathway can also run in reverse, so you can make linoleic acid out of arachidonic acid, too. We also now know that arachidonic acid works just as well for preventing EFAD symptoms.
P: Interesting…so which one of you is the true essential omega-6? Or does it even matter?
ARA: Well, it matters if you’re a baby. The pathway from linoleic acid to arachidonic acid doesn’t seem to operate well in human infants. For example, when babies are given a high-linoleic acid formula (free of arachidonic acid), their blood levels of arachidonic acid don’t rise, they plummet—while linoleic acid appears to simply pile up in the bloodstream. If babies could easily convert linoleic acid into arachidonic acid, you’d expect the opposite result.
It is well established that the infant’s brain requires arachidonic acid for proper growth and development. Human mother’s milk naturally contains significant quantities of arachidonic acid, whereas the milk of other mammals contains only trace amounts, suggesting I play a special role in human development. And get this: the human placenta actively transfers arachidonic acid from mother to fetus. Now I ask you–would evolution have installed this special delivery system for an inflammatory, disease-causing molecule? I think not–and the Food and Agriculture Association/World Health Organization agrees with me, as they began recommending many years ago that infant formula be fortified with arachidonic acid.
P: Mmm hmmm…
ARA: The other major problem is that we’re not sure how well the conversion from linoleic acid to arachidonic acid operates in adults either. In study after study, when scientists gave linoleic acid supplements to people eating a typical modern diet, arachidonic acid levels in the blood didn’t budge, even when very high doses of linoleic acid were used. Is this because this pathway is a poor generator of arachidonic acid? Or is it because the typical modern diet includes ready-made arachidonic acid from animal foods AND extremely high amounts of linoleic acid from vegetable oils. Maybe the system was already saturated with arachidonic acid and the pathway didn’t need to switch on to manufacture more? We don’t know. Are you following me so far?
P: [snoring] What? Oh…yes, yes, I completely agree. That’s fascinating.
ARA: Seriously? Did you fall asleep on me? I’d storm outta here right now except you’re the only psychiatrist in a 100-mile radius who takes my insurance, so I’m staying for the whole 50 minutes. Should I go over the science again?
P: No, I think I get the gist. You’re a vital molecule we can’t live without and it’s unclear if linoleic acid can completely replace you at all stages of life. Does this mean that people who don’t include animal foods in their diets don’t have enough arachidonic acid in their brains and bodies?
ARA: Unfortunately there is no way to measure arachidonic acid levels in the brains of living people. As for bloodstream levels, of the three very small studies I could find [one, two, three], only one showed that vegans had lower circulating arachidonic acid levels compared to omnivores. So it appears that adults may be able to maintain adequate blood levels of arachidonic acid without eating animal foods so long as they consume enough linoleic acid. Linoleic acid is present in reasonable amounts in whole plant and animal foods but is particularly easy to obtain from processed foods made with refined seed oils, aka “vegetable oils.” Soybean oil, for example, contains about 50% linoleic acid.
Source: Suzi Smith, used with permission
P: So, vegetable oil for the win!
ARA: Not so fast. Advocates for plant-based diets warn people about me causing inflammation, but they don’t usually warn people about linoleic acid causing inflammation. If linoleic acid turns into arachidonic acid, and arachidonic acid promotes inflammation, then linoleic acid does too, right? You can’t have it both ways. If you’re going to demonize one, you have to demonize the other. Instead, their mantra is “meat bad, vegetable oil good.”
P: So you’re BOTH bad?
ARA: No, I’m good. I’m GOOD I tell you. Yes, I cause inflammation, but I don’t just run around willy-nilly causing inflammation for inflammation’s sake. Why would I want to do that? I only mount an inflammatory response in reaction to real threats.
P: So why do so many people blame you for causing chronic inflammatory diseases?
ARA: All of those rumors about me come from epidemiological studies—deeply flawed, questionnaire-based guesses about the relationship between foods and diseases—not from scientific experiments. All of the human experimental studies conducted so far show that raising levels of arachidonic acid using supplements does NOT cause signs of unnecessary or harmful inflammation.
P: So it’s really a matter of personal choice then, right? People can decide whether they prefer to obtain arachidonic acid directly from animal foods or indirectly from linoleic acid found in plant foods?
ARA: Unless you’re an infant, the available science suggests you can meet your basic arachidonic acid requirements if you are consuming vegetable oils. Because research studies use vegetable oils as their source of linoleic acid, we don’t know whether you can meet your daily needs from whole food plant sources of linoleic acid, because as far as I know, those experiments haven’t been done, but it’s certainly plausible.
If people choose to include vegetable oils in their diets, as recommended by the USDA and the recent EAT-Lancet report, they should know that most vegetable oils are ultra-processed, industrially-produced and unnaturally, exceedingly high in linoleic acid compared to whole foods. Excess linoleic acid promotes inflammation by competing with EPA, an anti-inflammatory omega-3 fatty acid, so there is some risk involved in obtaining your omega-6s from vegetable oils. Somehow your species was able to survive for nearly two million years without processed vegetable oils, so how they suddenly came to be considered important to human health in the 20th century—not long after they were invented by food manufacturers—is a head-scratcher.
P: So our time is just about up. If I understand you correctly, what you’re saying is that the simplest, safest and most reliable way to guarantee you’re getting enough arachidonic acid is to include animal foods in your diet.
ARA: Exactly. If people are avoiding meat because they think it causes inflammation, they can relax. If they are worried about inflammation, they should pay attention to the refined vegetable oils like soybean and sunflower oil, and the refined carbohydrates like sugar, flour, fruit juice and processed cereals in their diet instead.
The jury is still out about whether I should be considered essential beyond infancy, but there’s no doubt that I am good for people. I’m a nice guy. Really I am. Hardworking, reliable, and multi-talented. Wow, I feel a lot better now that I’ve had a chance to vent. Thanks, Doc.
P: I’m glad you’re feeling some relief, but I don’t think you’re out of the woods yet. You’re up against a growing culture of anti-meat sentiment in this world. You are going to need ongoing support…I recommend years of intensive psychotherapy.
A: Who’s helping who here? Fine, you’re probably right. There are plenty of logical reasons why people should pay attention to me and consider me an essential nutrient, but because I only exist in animal foods, there’s tremendous emotional resistance to my existence. Arachiphobia is likely to spread….woe is me. Same time next week?