A new human study found that eating more linoleic acid—the main omega-6 fatty acid found in many seed oils—reduced levels of an important omega-3 fatty acid. Here’s why that matters, and why better nutrition is about more than simply avoiding certain foods.
Robert’s Note
I wrote this article after my interview with Dr. Artemis Simopoulos, one of the world’s leading researchers on omega-3 fatty acids and the importance of omega-6 to omega-3 balance.
During our conversation, you can hear her perspective—and her excitement—about the new clinical study that inspired this article. You can click here to watch the interview.
I’m also making a free copy of her book, The Healthiest Diet for You: Scientific Aspects, available to you. You can click here to access your free copy.
I hope this article helps you better understand how the foods you eat can actually change your biology.
Enjoy!
Most of us were taught to think about food in terms of calories.
How many calories does it have? How much protein? How many carbohydrates? How much fat? How much sugar?
Those things matter. But they don’t tell us the whole story.
Food doesn’t simply enter your stomach, provide some calories, and disappear. The nutrients and fats in the foods you eat provide raw materials your body can use.
Some of those fats can become part of your cell membranes. Some can be used to make chemical messengers. And changing the types of fats you eat can change the fatty acids measured in your body.
Food changes your biology.
A new randomized controlled human study published in Nutrients on June 4, 2026, gives us a fascinating example. Researchers changed the amount of linoleic acid (LA) people consumed and then measured what happened inside their bodies. [1]
Linoleic acid is the main omega-6 fatty acid found in many commonly used seed oils, including safflower, sunflower, corn, and soybean oils. It is also a major fatty acid in many oils sold simply as “vegetable oil.”
One of the most interesting findings was surprisingly simple:
When linoleic acid went up, an important omega-3 called eicosapentaenoic acid went down.
Eicosapentaenoic acid (EPA) is an important long-chain omega-3 fatty acid. EPA has been widely studied for its role in the body’s inflammatory pathways and as a building block for molecules involved in regulating and resolving inflammation. [1,2]
So why would eating more of one type of fat affect another type of fat?
That’s where this story gets interesting.
What Did the Researchers Do?
This wasn’t a mouse study.
It wasn’t a survey asking thousands of people what they remembered eating months ago.
Researchers conducted a randomized, double-blind dietary trial in humans. [1]
Participants were assigned to diets containing very different amounts of linoleic acid for 12 weeks.
One diet was designed to provide about 2.5% of calories from linoleic acid, while the other provided about 10% of calories from linoleic acid. Fifty-two participants completed the 12-week intervention. [1]
Importantly, researchers tried to change linoleic acid while keeping other important parts of the diets similar. This gave them a better look at what happened when linoleic acid itself changed.
Then they measured fatty acids in the participants’ blood.
The researchers found that people consuming the higher-linoleic-acid diet had markedly lower EPA concentrations. They also observed changes in other long-chain omega-3 fatty acids. [1]
Think about what that means.
The researchers changed the food.
Then they measured the blood.
The biology changed.
I especially recommend the change from “EPA is well researched for its anti-inflammatory properties for one” to the wording above. EPA is certainly involved in inflammatory biology, but calling EPA simply “anti-inflammatory” can oversimplify a much more interesting story involving EPA-derived lipid mediators and inflammation resolution. That actually sets us up perfectly for the later section on oxylipins.
One other thing I like about your edit: introducing the actual seed oils by name this early gives us an opportunity later in the article to explain where people are getting so much LA without realizing it—restaurant foods, mayonnaise, salad dressings, chips, sauces, packaged foods, etc. That could make the article even more practical without turning it into an anti-seed-oil piece.
What Is Linoleic Acid?
Linoleic acid is an omega-6 fatty acid.
And here’s something important that can easily get lost in the seed-oil debate:
Your body needs omega-6.
Linoleic acid is an essential fatty acid. “Essential” means our bodies cannot make it, so we have to get it from food.
Therefore, the message from this research should NOT be:
“Omega-6 is poison.”
It’s not.
The more useful question is:
How much are we getting, and what is happening to the balance between omega-6 and omega-3?
Linoleic acid occurs naturally in many foods, but it is especially concentrated in oils such as soybean, corn, sunflower, and safflower oils.
These oils are also widely used in fried foods, chips and snack foods, salad dressings, mayonnaise, sauces, baked goods, packaged foods, and restaurant meals.
That means you don’t have to keep a bottle of soybean oil in your kitchen to consume a lot of linoleic acid.
It can show up throughout the day without you even thinking about it.
The authors of the new study noted that linoleic acid typically provides about 6% to 9% of calories in a modern Western diet. [1]
And that brings us back to EPA.
EPA Went Down. Why Should We Care?
Eicosapentaenoic acid is one of the important long-chain omega-3 fatty acids.
EPA can become part of the body’s fatty-acid pools and can also provide raw material for chemical messengers involved in inflammation and other biological processes. [1]
Here’s an easy way to think about inflammation.
Imagine your body has a fire department.
If you cut your finger, twist your ankle, or develop an infection, you want the fire department to respond.
Inflammation is part of that response.
So, inflammation itself isn’t the enemy.
But after the emergency is handled, your body also needs ways to control and resolve that response.
You don’t want the firefighters spraying water through your house three weeks after the fire has been put out.
EPA can provide raw material for molecules involved in regulating inflammatory responses.
So, when researchers found that the higher-linoleic-acid diet resulted in lower EPA, that deserves our attention.
It doesn’t mean that lower EPA automatically causes disease.But it raises an important question:
What happens to our fatty-acid balance when EPA goes down?
Think of Omega-6 and Omega-3 Like Traffic
Omega-6 and omega-3 fatty acids aren’t operating in completely separate worlds.
Imagine two groups of cars traveling toward a city.
One group represents omega-6.
The other represents omega-3.
At certain points, both groups need to use some of the same roads, intersections, and toll booths.
Something similar happens inside the body.
Linoleic acid begins an omega-6 pathway.
Alpha-linolenic acid (ALA) begins an omega-3 pathway.
These pathways use some of the same enzymes to make longer-chain fatty acids. [1]
Now imagine suddenly putting many more omega-6 cars on those shared roads.
The omega-3 cars haven’t disappeared.
But now there is more competition for some of the same machinery.
The researchers concluded that increasing dietary linoleic acid appeared to affect these shared pathways and reduce the amount of long-chain omega-3 fatty acids, particularly EPA. [1]
And that’s what they measured:
More linoleic acid. Lower EPA.
That gives us a much more useful conversation than simply asking whether a particular food or oil is “good” or “bad.”
Sometimes What Goes Down Matters as Much as What Goes Up
Another important finding involved arachidonic acid (AA).
Arachidonic acid is an omega-6 fatty acid.
Interestingly, researchers did not find a significant difference in arachidonic acid concentrations between the two diets. [1]
That’s important.
Someone might assume:
“If people eat more linoleic acid, arachidonic acid must shoot through the roof.”
That’s not what happened in this study.
But remember what DID happen:
EPA went down.
That meant the relationship between arachidonic acid and EPA changed.
The AA-to-EPA ratio increased significantly in the high-linoleic-acid group. [1]
Here’s a simple way to understand why.
Imagine you have:
10 red balls and 5 blue balls.
The ratio is:
10 ÷ 5 = 2
Now keep the 10 red balls but remove three blue balls.
You now have:
10 red balls and 2 blue balls.
The ratio becomes:
10 ÷ 2 = 5
You didn’t add a single red ball.
But the balance changed dramatically because the number of blue balls went down.
That’s similar to what makes the EPA finding so interesting.
Arachidonic acid didn’t have to increase significantly for the relationship to change.
EPA decreased.
And when EPA decreased, the AA-to-EPA ratio increased.
Sometimes we become so focused on whether one thing is too high that we forget to ask whether something else may be too low.
Your Fats Can Become Messages
Here’s where the study gets even more interesting.
The fats in your body aren’t simply sitting around doing nothing.
Some fatty acids can be converted into compounds called oxylipins.
Think of oxylipins like text messages sent between cells.
Different fatty acids provide the raw materials for different messages.
Researchers wanted to see whether changing dietary linoleic acid would also change the kinds of lipid messengers participants’ blood cells could produce under controlled conditions.
They stimulated blood samples in the laboratory and measured the resulting oxylipins.
Two of the molecules they examined were 5-hydroxyeicosatetraenoic acid (5-HETE), which is made from arachidonic acid, and 5-hydroxyeicosapentaenoic acid (5-HEPE), which is made from EPA.
The ratio of AA-derived 5-HETE to EPA-derived 5-HEPE was consistently higher in the high-linoleic-acid group. [1]
The researchers described the findings as a shift toward a more omega-6-dominant inflammatory lipid-mediator profile. [1]
But we need to understand exactly what that means.
It does not mean the study proved that everyone eating the higher-linoleic-acid diet suddenly developed chronic inflammation.
The researchers stimulated blood samples outside the body under laboratory conditions.
What it does show is fascinating:
Changing the fats people ate changed the raw materials available for certain biological messages.
Again:
Food changed biology.
Omega-6 Isn’t the Enemy
This is where nutrition conversations can quickly become too extreme.
Someone may read this study and say:
“See! Omega-6 is bad.”
That’s not what I’m saying.
And that’s not what this study proves.
Your body needs omega-6.
Your body also needs omega-3.
Think of it like driving a car.
Your car needs an accelerator.
Your car also needs brakes.
It wouldn’t make sense to say:
“Brakes are good, so let’s remove the accelerator.”
You need both systems.
The goal is for them to work together.
That’s why I believe the better conversation is about balance, not fear.
And there’s another part of this conversation that may be even more important.
Avoiding Certain Foods Is Only Half the Solution
Let’s say you read this article and decide:
“I’m going to cut back on foods made with high-linoleic-acid seed oils.”
Okay.
But I have another question:
Are you getting enough EPA and docosahexaenoic acid?
Docosahexaenoic acid (DHA) is another important long-chain omega-3 fatty acid.
Because removing something is only half of the equation.
Imagine you’re trying to fill a bathtub.
You notice that the drain is wide open.
So you close the drain.
Great.
But what happens if you never turn on the faucet?
The bathtub still doesn’t fill.
Nutrition can work the same way.
We spend enormous amounts of time telling people what they shouldn’t eat.
Don’t eat this.
Avoid that.
Cut back on this.
Stop eating that.
But we don’t spend nearly enough time asking:
What does my body need that I’m not giving it?
When we’re talking about fatty-acid balance, getting enough EPA and DHA is part of that conversation.
Getting Omega-3 Isn’t Always as Simple as It Sounds
EPA and DHA are found primarily in seafood, especially fatty fish such as salmon, sardines, mackerel, herring, anchovies, and trout.
Plant foods such as walnuts, flaxseed, and chia seeds contain alpha-linolenic acid.
ALA is important.
But ALA is not the same thing as EPA or DHA.
The human body can convert some ALA into longer-chain omega-3 fatty acids, but that conversion is limited.
And remember our traffic analogy.
The omega-6 and omega-3 pathways can use some of the same metabolic machinery.
This new study adds an important piece to that story because researchers found that increasing linoleic acid was associated with lower EPA. [1]
So when someone tells me:
“I eat walnuts, so my omega-3 must be great,”
or:
“I eat salmon sometimes, so I’m sure my omega-3 is fine,”
I have a simple question:
How do you know?
And that’s where testing becomes interesting.
The Fuel-Gauge Problem
Imagine getting into your car and wondering:
“How much gas do I have?”
You could try to remember.
“I filled it up last week.”
“I don’t think I’ve driven very far.”
“I usually keep plenty of gas in my car.”
Or you could do something much easier:
Look at the fuel gauge.
That’s how I think about fatty-acid testing.
Someone can tell me:
“I take an omega-3 supplement.”
“I eat salmon.”
“I avoid seed oils.”
“I eat healthy.”
Those statements tell me something about what they’re putting into their body.
They don’t necessarily tell me what we will measure in their blood.
There’s a difference between:
What you eat
and
What we measure.
That’s why testing can add valuable information.
This Is Where the BalanceTest Becomes Interesting
One tool I use to look at fatty-acid status is the BalanceTest, an at-home dried blood spot (DBS) test.
A person collects a small amount of blood from a fingertip. The sample is then analyzed to provide information about fatty-acid status and balance.
Now think about what researchers found in the new randomized controlled trial:
Higher linoleic acid intake → lower EPA.
And:
The AA-to-EPA ratio increased.
That makes measuring fatty acids particularly interesting.
Instead of saying:
“I think I’m getting enough omega-3.”
We can ask:
“What does the test actually show?”
There is an important scientific distinction here.
The new linoleic-acid study did not study the BalanceTest or BalanceOil+.
It does not prove that BalanceOil+ treats or prevents disease, and it does not validate every target range used by a commercial fatty-acid test.
Those are separate questions.
But the new study reinforces a much more basic idea:
Diet can change measurable fatty-acid biology.
And if we can measure something meaningful, we don’t always have to guess.
Test, Don’t Guess
I use a simple phrase:
Test, don’t guess.
Not because one test can tell us everything about someone’s health.
It can’t.
A fatty-acid test doesn’t diagnose every disease.
It doesn’t predict exactly what will happen to you in the future.
And one number should never be used to declare someone completely “healthy” or “unhealthy.”
But testing can answer a question guessing cannot:
What fatty acids are actually present in the sample we measured?
That gives us a starting point.
Then we can make changes.
And later, we can measure again.
Think about how normal this approach already is in health care.
If we’re concerned about blood pressure, we measure blood pressure.
If we’re concerned about blood sugar, we may measure glucose and hemoglobin A1C (HbA1c).
If we’re concerned about cholesterol and triglycerides, we order a lipid panel.
We don’t simply say:
“I’ve been eating better, so I’m sure everything improved.”
We check.
The same basic idea can be applied to fatty acids:
Measure → Make Changes → Measure Again
That’s very different from:
Guess → Hope → Assume
What This Study Does NOT Prove
Whenever a new nutrition study gets attention, people tend to take the findings much farther than the researchers did.
So let’s be very clear.
This study did not prove that seed oils cause heart disease, cancer, Alzheimer’s disease, diabetes, obesity, stroke, or any other chronic disease.
That’s not what the researchers studied.
The intervention lasted 12 weeks and involved healthy adults. Researchers examined fatty acids and lipid-mediator biology. [1]
So I would not take this study and say:
“This proves seed oils cause disease.”
It doesn’t.
But we shouldn’t make the opposite mistake either and pretend the findings don’t matter.
The researchers changed an important part of the participants’ diets.
Then measurable biological changes followed:
Higher linoleic acid.
Lower EPA.
Higher AA-to-EPA ratio.
Changes in the balance of certain fatty-acid-derived signaling molecules.
Those findings are important enough without exaggerating them.
Maybe We’re Asking the Wrong Nutrition Question
For decades, much of nutrition has focused on restriction.
What should I stop eating?
What should I cut out?
What’s bad for me?
Those can be useful questions.
But perhaps we need another question sitting right beside them:
What does my body need more of?
Reducing foods that provide large amounts of linoleic acid may be one way someone chooses to change their overall dietary pattern.
Making sure the body receives enough omega-3 fatty acids is another part of the conversation.
Think about a garden.
A healthy garden isn’t created simply by pulling weeds.
You also have to provide water, sunlight, good soil, nutrients, and the right seeds.
Your body is no different.
Health isn’t only about removing things that may work against you.
It’s also about providing the raw materials your body needs to work for you.
Food Changes Your Biology
This new study doesn’t end the debate over seed oils.
Science rarely works that way.
But it gives us another important piece of the puzzle.
Researchers changed the amount of linoleic acid people consumed.
Their biology responded.
EPA went down.
The AA-to-EPA relationship changed.
And the balance of certain fatty-acid-derived signaling molecules changed. [1]
That should cause us to think differently about food.
Food isn’t simply:
calories in and calories out.
Food provides building materials.
The fats you eat can influence the fatty-acid environment inside your body.
So don’t only ask:
“What should I stop eating?”
Also ask:
“What am I not getting enough of?”
And when there’s a meaningful way to measure something instead of assuming:
Test, don’t guess.
Because every meal provides your body with raw materials.
Meal after meal, day after day, those choices can influence the biological environment your body has to work with.
Food changes your biology—for better or for worse.
Ready to Find Out What YOUR Numbers Look Like?
After reading this article, you may be wondering:
“What does my omega-6 and omega-3 balance look like?”
That’s where testing can help.
You can eat salmon.
You can take an omega-3 supplement.
You can reduce foods containing seed oils.
You can believe you’re doing everything right.
But without measuring your fatty acids, you don’t actually know what your fatty-acid profile looks like.
That’s why I prefer a simple approach:
Test → Make Changes → Retest
If someone shared this article with you, contact that person and ask them how you can learn more about the BalanceTest.
You can also contact me at robert@dietfreelife.com.
My Recommendation: BalanceOil+
There are different ways to increase your intake of EPA and DHA. Food—especially fatty fish—is one option. Omega-3 supplements are another.
One product I personally recommend is BalanceOil+ from Zinzino.
Important Disclosure
For full transparency, I am an independent Zinzino partner and earn commissions when products are purchased through my partner link below. The scientific study discussed in this article did not study Zinzino, BalanceOil+, or the BalanceTest. My recommendation of these products is separate from the findings of the study.
This places the disclosure directly with my product recommendation so you know about my financial relationship before deciding whether to purchase. The Federal Trade Commission recommends that commission relationships be disclosed clearly and conspicuously and says that, for affiliate marketing, the closer the disclosure is to the recommendation, the better. [3]
Here’s How the Program Works
For customers in the United States, the current Balance Test Basic Kit is listed at $127 to start and $47 per month through Zinzino’s Subscribe & Save program. The kit includes BalanceOil+ and BalanceTests.
When choosing the BalanceOil+, my personal flavor recommendation is Orange Lemon Mint.
Here’s what I particularly like about this approach:
You test first.
You establish your starting point.
Then you use BalanceOil+ consistently while making appropriate dietary changes.
After 120 days, provided the subscription remains active and paid, Zinzino states that the second BalanceTest is provided free of charge. That gives you the opportunity to compare your before and after fatty-acid results.
And here’s the part I believe is important:
Don’t assume your numbers improved. Measure them.
Did your EPA change?
Did your DHA change?
Did your overall fatty-acid profile change?
Did the relationship between your omega-6 and omega-3 fatty acids change?
That’s the value of having a before-and-after measurement.
You’re not simply saying:
“I’ve been taking this for four months, so it must be working.”
You’re asking:
“What actually happened to my numbers?”
Because prices and subscription terms can change, check the current information on Zinzino’s ordering page before purchasing. As of this writing, Zinzino lists the program at $127 initially and $47 per month, says there is no commitment and that subscribers can cancel, and states that the second BalanceTest is sent after 120 days if the subscription is active and fully paid.
Learn More & Order the BalanceTest + BalanceOil+
You can also email me at robert@dietfreelife.com.
If someone shared this article with you, I encourage you to contact that person first so they can help you with the next steps.
The goal isn’t simply to take another supplement.
Know where you’re starting. Make meaningful changes. Give your body time to respond. Then measure again and see what actually changed.
Test, don’t guess.
References
-
- Sergeant, S., Easter, L. H., Mustin, T., Ivester, P., Legins, J. A., Seeds, M. C., Standage-Beier, C. S., Cox, A., Furdui, C. M., Hallmark, B., & Chilton, F. H. (2026). Effect of dietary linoleic acid intake on eicosapentaenoic acid status and lipoxygenase-mediated oxylipin biosynthesis in healthy adults: A randomized controlled trial. Nutrients, 18(11), Article 1814.
- National Institutes of Health, Office of Dietary Supplements. Omega-3 fatty acids: Fact sheet for health professionals.
NIH Omega-3 Fatty Acids Fact Sheet - Federal Trade Commission. (2023). FTC’s Endorsement Guides: What people are asking. The guidance explains disclosure requirements for affiliate marketers who earn commissions from purchases made through their links.
FTC Endorsement Guides - Zinzino. Balance Test Basic Kit. Current U.S. product information lists the starter kit, monthly Subscribe & Save price, and second BalanceTest after 120 days for qualifying active subscriptions.
Zinzino Balance Test Basic Kit
- Sergeant, S., Easter, L. H., Mustin, T., Ivester, P., Legins, J. A., Seeds, M. C., Standage-Beier, C. S., Cox, A., Furdui, C. M., Hallmark, B., & Chilton, F. H. (2026). Effect of dietary linoleic acid intake on eicosapentaenoic acid status and lipoxygenase-mediated oxylipin biosynthesis in healthy adults: A randomized controlled trial. Nutrients, 18(11), Article 1814.
__________
Robert Ferguson is a California- and Florida-based single father of two daughters, clinical nutritionist, Omega Balancing Coach™, researcher, best-selling author, speaker, podcast and television host, health advisor, NAACP Image Award Nominee, creator of the Diet Free Life methodology, and Chief Nutrition Officer for iCoura Health. He also serves on the Presidential Task Force on Obesity for the National Medical Association and the Health and Product Advisory Board for Zinzino, Inc.
🗓️ Schedule a FREE consultation with Robert Ferguson about becoming a client: SCHEDULE FREE CONSULTATION
👉🏽 To order the BalanceOil+ with the BalanceTEST, > CLICK HERE
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