Learn the amazing benefits of fish oil and omega-3 for health, heart, brain and children.

Why Do Vegetable Oils Increase Inflammation?

The average reader on this site has probably heard that vegetables oils increase inflammation and wreak havoc on your body’s immune system.

Usually, people take this seriously — while others simply dismiss this nutritional fact because they aren’t sure what it means or (more likely) wonder if there’s any real science to support this claim.

Here’s the thing, though…

Vegetable Oils DO Increase Inflammation.

In scientific communities, this claim is not up for debate. Rather, it’s a well known fact that consuming too many vegetable oils will trigger your body’s inflammation response.

Let’s talk about why.

Vegetable Oils Are Loaded With Omega-6

As it turns out, vegetable oils are packed full of omega-6s in the form of linoleic acid, or LA.

Specific sources of “BAD”, or inflammatory omega-6s include:

  • Soybean oil
  • Peanut oil
  • Grapeseed oil
  • Sesame oil
  • Corn oil

At this point, you might be wondering….

What About Supplements That Advertise Omega-6s?!

In small amounts, omega-6 is a good thing.

Yep, no joke.

But that’s not the whole story…

In and of itself, omega-6 really isn’t too bad because when it’s in the form of LA, it can be converted into GLA — which is one oddball omega-6 that happens to have positive health benefits.


Your body can actually convert some of this GLA into DHA (yep – an ingredient you can get directly from fish oil) and that’s why you sometimes see omega-6 included in supplements.

Sources of “good”, or anti-inflammatory omega-6s are:

  • Borage oil
  • Primrose oil
  • Black currant seed oil

But, we started out talking about why vegetable oils increase inflammation.

Let’s get back to that.

The downside with vegetable oils is that it has too many omega-6s in the wrong form. And, too much omega-6 will cause the body to produce an excess of hormone-like chemical signals.  That’s a major problem because inflammation is largely responsible for chronic conditions like obesity, crohn’s disease, arthritis, etc.

So What Happens After You Eat Vegetable Oils?

When fish and vegetable oils are digested something of a chain reaction happens inside your body. During this process, prostanoids (which are a particular class of eicosanoids, which you can read more about here) are released.

These special eicosanoids tell your body whether to increase or reduce inflammation. In small amounts, these signals help your body fight off allergies, regulate blood pressure, and defend against illness.

In large amounts, these signals can lead to chronic health conditions. Too many signals will force markers of inflammation (such as C-reactive proteins, tumor necrosis factor, and IL-6) through the roof.

Many different chemical reactions start occurring in the body and quality of life goes down the drain.

Not pretty.

What’s more, research indicates that women are more susceptible to inflammation caused by vegetable oils. According to an article published in the journal of Clinical Nutrition, women who consumed vegetable oils had inflammation markers that were anywhere from 45-76% higher than those who did not.

But Fish Oil Lowers Inflammation, Right??

Plenty of people think taking fish oil is enough to protect you from the harmful side effects of vegetable oils.

But, they’re only half right…

Sure, fish oil is an anti-inflammatory. However, important new studies (like this one) show that taking fish oil only *lessens* the anti-inflammatory effects of vegetable oils; it does not completely mitigate them.

In fact, fish oil only blocks HALF of the negative effects from vegetable oils.

Here’s something else that might surprise you…

Vegetable Oils Can ‘Prime’ You To Crave MORE Inflammatory Foods

It’s true. Consuming lots of vegetable oils can also have the effect of making you want more inflammatory foods. Studies show that high levels of omega-6 found in vegetable oils may be linked to emotional eating, poorer impulse control, and depression.

Perhaps more importantly, the link between depression and essential fatty acids is strongest not when omega-3 is low — but when omega-6 is HIGH.

So Should You Give Up Vegetable Oils?

Not necessarily.

There was a time when the average American diet was closer to the healthy ideal — when people consumed less processed meats, more vegetables, and fewer foods cooked in pro-inflammatory vegetable oils.

Now, figures suggest the typical American diet is 10x higher in omega-6s. This imbalance is not without consequence, either. Scientific literature is replete with evidence showing unbalanced omega-3s contribute to depression and other mental disorders.

In my opinion, swearing off entire food categories (no matter how nutritionally bankrupt they are) is the easiest way to set yourself up for failure.

Instead, aim for an omega-3 to omega-6 ratio of 1:2. The easiest way know what your levels actually are is to get an SIP test. You can also estimate your levels by using your fasting cholesterol levels — drop Marshall a line for instructions.