seed oils: inflammation is complicated
untangling the facts about omega-6 fats, inflammation, and where linoleic acid fit in the conversation
This is the final installment in my seed oil series (for now!), and I’d love to dive into animal fats in the future. Last week, we chatted about omega-6’s and omega-3’s and the overarching effects that they both have in health. This week we’re going to drill down into a specific omega-6 from seed oils: linoleic acid, and its inflammatory effects.
Linoleic acid is consistently in the crosshairs of seed oil crusaders, sometimes for valid reasons, and sometimes less so. Let’s break it down.
the linoleic acid to arachidonic acid pipeline
Linoleic acid is a polyunsaturated fatty acid, or PUFA, that has two double bonds in its chain. If you read last week’s post, it would be the computer charger in the metaphor. It’s the most widely consumed PUFA and is a…gasp!...omega-6. While our modern omega-6 to omega-3 ratio is roughly double the ratio associated with positive health outcomes, omega-6s are still essential for our bodies.
Where many folks take umbrage with linoleic acid, is that it can metabolize (or breakdown) to compounds that cause chronic inflammation. To start off the metabolism, the double bonds in the linoleic acid turn into single bonds to create gamma-linolenic acid, which is used to reduce inflammation on the skin.
Huh, weird. The metabolite reduces inflammation? Fine, fine, but gamma-linolenic acid must eventually break down into something inflammatory, right? Well, the next step in the chain produces eicosatetraenoic acid (ETA). And while ETA can cause inflammation in certain doses, it also alleviates it. And this ETA finally gets metabolized at least one more time to produce the Grand Daddy of all seed oil worriers’ nightmares: arachidonic acid.
the role of arachidonic acid
Unlike ETA, arachidonic acid doesn’t play both sides of the field. It’s critical for cell regulation but also contributes to inflammation cascades in the body.
Here’s the catch, though: the conversion of linoleic acid to arachidonic acid is highly inefficient. Only 0.3–0.6% of linoleic acid molecules are metabolized into arachidonic acid. In fact, most of the arachidonic acid in our bodies doesn’t come from linoleic acid, it’s consumed directly from meat, poultry, eggs and dairy (another source says so too).
To make things even more confusing, studies show that directly consuming linoleic acid and/or arachidonic acid doesn’t impact inflammation markers. Even consuming five times the baseline amount has no measurable effect on inflammation.
cool, so what are you trying to tell us here?
The anti-seed oil argument tends to boil down to something like:
“Seed oils cause inflammation because of omega-6’s”
Where a more accurate, nuanced version would be:
“Seed oils typically have increased levels of omega-6’s, like linoleic acid which can inefficiently breakdown to pro-inflammatory arachidonic acid, which we consume mainly not from seed oils, but animal products. *Inhale* And when you consume them, linoleic acid or arachidonic acid show little to no effect on inflammation.”
When I started writing this whole series, I wasn’t entirely sure where I stood on the seed oils discussion. I recall looking at and buying Zero Acre Farms after reading about seed oils about two years ago. And then I reverted back after a cursory look at the process about a month after that. Now that this seed oil question has grown to the point of an app with hundreds of thousands of followers, and Make America Healthy Again now takes full effect this week, I thought it was worth more investigation.
The point I’m ultimately trying to make is that we should be wary of demonizing something just because it’s in vogue and someone “important” is “telling” us why we should. For me, the takeaway isn’t that we need to avoid omega-6s at all costs. Instead, it’s that I should focus on increasing my omega-3 intake for better balance.
Thank you for subscribing and letting me take you on this exploration.