Omega-3, Omega-6, and Inflammation: What Actually Matters?

Inflammation has gotten a pretty bad reputation.

We’re told to eat an “anti-inflammatory diet,” avoid inflammatory foods, and keep inflammation as low as possible. But inflammation isn’t inherently bad. When you cut your finger, your body needs an inflammatory response. When you encounter an infection, your immune system needs to respond. Inflammation is part of how the body recognizes a problem and begins dealing with it.

The goal isn’t to eliminate inflammation. The goal is to regulate it and, when the job is done, resolve it.

That’s where dietary fats get interesting.

You’ve probably heard that omega-3 fatty acids are anti-inflammatory and omega-6 fatty acids are inflammatory. There’s a kernel of truth behind that idea, but the biology is considerably more complicated than the “good omega versus bad omega” story we often hear.

First, a little fat biology

Omega-3 and omega-6 fatty acids are both polyunsaturated fats, and both are important to human biology. Some are considered essential because our bodies cannot make them from scratch and we need to obtain them from food.

The major dietary omega-6 fatty acid is linoleic acid (LA). The major plant-based omega-3 is alpha-linolenic acid (ALA). ALA can be converted into longer-chain omega-3 fatty acids, including EPA and DHA, although the conversion is limited and varies between individuals. EPA and especially DHA can also be obtained directly from foods such as fatty fish and certain algae. 

These fatty acids don’t just sit around waiting to become “inflammation.” They become part of cell membranes and serve as starting materials for a whole family of signaling molecules that help regulate immune activity, blood vessels, platelet function, and other physiological processes.

And this is where the old omega-6 story starts to fall apart.

Omega-6 isn’t the enemy

For years, nutrition advice has often boiled down to something like this: omega-6 equals inflammation, omega-3 equals anti-inflammatory, therefore we should eat less omega-6 and more omega-3.

It sounds wonderfully simple. It also isn’t quite right.

Linoleic acid is an essential fatty acid, and human studies do not support the idea that simply increasing dietary linoleic acid causes chronic inflammation. In a systematic review of randomized controlled trials, increasing linoleic acid did not significantly increase a wide range of inflammatory markers. A later meta-analysis of 30 randomized trials similarly found no significant overall effect of higher linoleic acid intake on CRP, IL-6, TNF-α, or several other inflammatory markers. 

That doesn’t mean we should eat unlimited amounts of every food containing omega-6.

It means we need to pay attention to the whole food and dietary pattern, rather than labeling an individual fatty acid as inherently inflammatory.

There is also a lot of discussion about the ratio of omega-6 to omega-3 in the diet. You may have seen claims that we should achieve a particular ratio, such as 1:1 or 4:1.

I don’t think that’s the most useful way to think about it anymore. The omega-6:omega-3 ratio has theoretical appeal, but human research has found it to be a relatively poor standalone measure of health risk. Increasing actual intake and tissue levels of EPA and DHA may tell us considerably more than trying to force two broad classes of fatty acids into a particular mathematical ratio. 

In other words, I don’t want you obsessing over the ratio on your plate.

I’d rather ask a different question: Are you getting enough omega-3s?

Omega-3s do something pretty fascinating

This is where I think the story gets much more interesting than “omega-3s are anti-inflammatory.”

EPA and DHA can serve as precursors for a group of lipid mediators called specialized pro-resolving mediators, or SPMs. These include resolvins, protectins, and maresins.

The word resolving is important.

SPMs aren’t simply another way of suppressing inflammation. They are involved in the body’s active process of bringing an inflammatory response to an appropriate close while helping coordinate tissue repair and return toward normal function. 

That distinction matters.

If inflammation is part of the body’s emergency response, we don’t necessarily want to slam the brakes on the emergency response before the job is finished. We want the response to be appropriately activated, controlled, and resolved.

That is a much more sophisticated story than “inflammation bad, omega-3 good.”

And then there’s your gut

This is where I get particularly interested in omega-3s.

We often talk about dietary fats as though they go directly from our plate into our bloodstream and that’s the end of the story. But what we eat first encounters the gastrointestinal tract and the enormous microbial ecosystem living there.

And emerging research suggests that omega-3 fatty acids interact with the gut microbiome as well as the intestinal immune system. Human studies have found that omega-3 supplementation can change the abundance of certain bacterial groups, although the changes aren’t consistent enough for us to say that omega-3s simply “create a healthy microbiome.” 

One randomized trial found that omega-3 supplementation increased several bacterial genera, including some associated with short-chain fatty acid production. Another human trial found changes in gut microbial composition and microbial fermentation products following omega-3 supplementation. 

That’s fascinating because it gives us another example of how nutrition doesn’t operate in isolated compartments.

The food affects the gut. The gut influences the immune system. The immune system interacts with metabolism. And the fatty acids we consume become part of signaling pathways throughout the body.

We don’t need to decide that omega-3s are “good for the gut” in some universal sense to appreciate that relationship. The microbiome is enormously individual, and the response to a dietary intervention can vary. But the gut is clearly part of the conversation.

What about plant-based omega-3s?

This is one of my favorite parts of the omega-3 story because you don’t need to eat fish to consume omega-3 fatty acids.

ALA is found in a variety of plant foods, including:

• flaxseeds and flaxseed oil
• chia seeds
• walnuts
• hemp seeds
• soybeans and some soy foods
• canola/rapeseed oil
• perilla and some other plant oils

Some plants also contain stearidonic acid (SDA), another omega-3 fatty acid that can be converted to EPA more readily than ALA, although SDA-rich foods are less common in the typical American diet. 

Your body can convert ALA into EPA and DHA. The catch is that the conversion isn’t especially efficient, particularly when it comes to DHA. Research consistently finds that ALA can contribute to EPA status, while conversion all the way to DHA is much more limited. There are also differences between individuals, including differences associated with sex and hormonal status. 

So if you’re plant-based, don’t hear this as “plant omega-3s don’t count.” They absolutely count.

Flax, chia, walnuts, hemp, and other ALA-rich foods are wonderful additions to a nutrient-dense diet and provide much more than just ALA. They’re also bringing fiber, minerals, protein, polyphenols, and other compounds to the table.

But if you’re specifically trying to increase EPA and DHA, it is useful to know that getting those preformed fatty acids from fatty fish or algae is a different proposition from relying exclusively on ALA conversion. Algae-derived DHA and EPA can be particularly useful for people who don’t eat seafood.

So what should you actually eat?

This is where I think nutrition advice gets unnecessarily complicated.

Instead of worrying about whether a particular oil has “too much omega-6,” I would start with the foods you’re actually eating.

Aim for a diet that includes a variety of minimally processed foods, including nuts and seeds, vegetables and fruits, legumes when tolerated, whole grains and other fiber-rich carbohydrates, and sources of quality protein and fat.

Then make a point of regularly including omega-3-rich foods.

That might look like salmon, sardines, trout, herring or mackerel if you eat seafood. It might also include chia or ground flax in oatmeal or a smoothie, walnuts on a salad, hemp seeds on vegetables, or an algae-derived omega-3 if you don’t eat fish.

And remember that whole-food sources are bringing much more to the table than a single fatty acid. A handful of walnuts isn’t just an omega-3 delivery system. It’s a food containing fiber, minerals, protein, polyphenols, and other compounds that interact with the rest of your diet and your gut microbiome.

That’s ultimately the way I like to think about nutrition.

We’re not eating individual nutrients. We’re eating foods, and those foods interact with our bodies in complicated ways.

The bigger picture

I don’t think the takeaway from the omega-3 story is that you need to fear omega-6 fats or spend your life calculating an omega-6:omega-3 ratio.

It’s also not that taking a fish oil supplement automatically “turns off” inflammation.

The more interesting takeaway is that our bodies have sophisticated systems for regulating inflammation, and the fats we eat are one piece of that system.

Omega-3 fatty acids become part of cell membranes and serve as precursors to signaling molecules, including specialized pro-resolving mediators. They interact with immune pathways and may influence the gut microbiome. Plant foods can provide the essential omega-3 ALA, while seafood and algae provide preformed EPA and DHA. And omega-6 fatty acids are not simply the inflammatory villains they’re sometimes made out to be. 

That’s a much more useful place to land than a 1:1 ratio.

Feed the system. Give your body the raw materials it needs. Eat a diverse diet. And let biology be more complicated than the headline.