Linoleic acid in sunflower and soybean oil promote inflammation

The linoleic acid in sunflower and soybean oil promotes inflammation by altering the omega-6 to 3 ratio; this has been shown to increase the prevalence of IBD.

A diet high in linoleic acid has long been connected to inflammatory bowel disease; yet it is an "essential" fatty acid. We cannot live without it.

Sunflower oil is inflammatoryGood in small amounts.

Linoleic acid

Too much of a good thing

Linoleic acid is an essential fatty acid. Human bodies cannot synthesise it and so it must be obtained from our food. It forms an extremely important part of cell membranes, controlling the movement of water across the skin barrier in particular.

But it is an omega-6 fat, so in excess it becomes inflammatory. As the parent of arachidonic acid, too much of a good thing may lead to the excessive and prolonged release of eicosanoids after injury; via the cyclooxygenase enzyme pathway and hence the development of drugs called NSAIDs which block this mechanism.

Soybean oil also contains some ALA, alpha linolenic acid, an omega 3 fat; that which is anti-inflammatory, but the amount is relatively small.

The Greek omega symbol is often used; thus Ω-3.

Be careful not to confuse linoleic acid with linolenic; they are poles apart.

Soybean oil

  • PUFAs
  • Linoleic acid Ω-6
  • Linolenic acid Ω-3

58g of total PUFAs/100g

51g linoleic acid

6.6g linolenic acid

Ratio of Ω-8/ Ω-3

= 51/6.6

= 7.7

The ideal ratio for omega-6 to 3 is generally considered below 4. In soybean oil it is nearly double; that is considered inflammatory.

Sunflower oil

  • PUFAs
  • Linoleic acid Ω-6
  • Linolenic acid Ω-3
  • Oleic acid MUFA

85g of total PUFAs/100g

60g linoleic acid

± zero ALA Ω-3

40 g oleic acid

Ratio of Ω-6/ Ω-3

= extremely high

When considering the ratio of omega-6 to 3 it is extremely high; however the saving grace of sunflower oil is its oleic acid content. In addition it also contains relatively large amounts of vitamin E.

Oleic acid is the fat that is considered to make olive oil and avocados so nutritious.

High temperature solvent extraction

Another negative in the use of both soybean and sunflower oils is that the fat is extracted using a solvent, hexane, at high temperatures; the vitamin E is destroyed. They are now considered highly processed foods that contribute large amounts of energy but little in the way of nutrients.

10% of our energy requirements

Due to the excessive consumption of soybean and sunflower oils the average person eating typical grocery store food, the so-called industrial diet, is today getting around 10% of their energy requirements from linoleic acid. But our bodies require less than 2 percent.

This huge rise in the amount of this omega-6 fat in our food has upset the apple cart; it throws the ratio of six to three way out of balance. The extreme increase in the amount of linoleic acid in sunflower and soybean oil consumed coincides with the increase of inflammatory diseases in the last fifty years; but is it the cause?

And what is the mechanism?

Inflammatory bowel disease

A new study from the University of California[1] confirms what scientists already knew; that the huge increase in these oils in processed foods was causing ulcerative colitis, obesity and diabetes. But what they were looking for was the mechanism by which this was happening.

Now we know; it's due to the adverse affect on the microbiome.


Endo-cannabinoids are naturally occurring neurotransmitters; in many complex ways they target cells all over the body helping to keep us in balance. For example they help regulate sleep, appetite and generalised inflammation, amongst many other functions[2].

They are produced naturally by many different tissues in the brain, muscles and circulating cells, for example. What astonished the researchers at UC was they found that the friendly bacteria in the gut, the so-called microbiome, also produce these helpful cannabinoids that assist in regulating the body's functions; especially protection against inflammatory bowel disease.

These endo-cannabinoids are formed from enzyme action on the important omega 3 fatty acids.

"Enzymes that metabolize fatty acids are shared between two pathways. If you swamp the system with linoleic acid, you'll have less enzymes available to metabolize omega-3s into good endocannabinoids." 

- Professor Frances Sladek

E. Coli

Here's the catch. E.coli in the gut, a pathogen, thrives on linoleic acid; and in the research was strongly linked to a decrease in these good cannabinoids. The body has greater difficulty getting back into balance after being tipped over for one reason or another; we become more prone to chronic inflammatory diseases.

As the amount of linoleic acid from our food increases, above that essential 2%, E. coli flourish and the helpful bacteria die off according to Dr Frances Sladek, professor of cell biology at UC; and the Endo-Cannabinoid System is thus also negatively affected.


As the friendly bacteria in the gut die off from high levels of linoleic acid, not only do the cannabinoids decrease; the amount of oxylipins which are strongly correlated with obesity simultaneously increase.

These industrial diet oils make us fat and our bodies angry not just from increased calories but also because they disturb profoundly important things going on in the body; like the Endo-Cannabinoid System and the microbiome. Generalised inflammation is the result; pain and chronic diseases like diabetes.

Leaky gut

Without getting into the complex science, the researchers have found that high levels of the omega 6 linoleic acid, found for example in sunflower and soybean oils also weaken the intestinal barrier; that allows noxious substances in the gut into the blood stream.

It also explains why a high omega 6 to 3 ratio has long been associated with generalised inflammation and pain in the body.

Broad beans yield large amounts of fibre and the L-dopa that the body needs to synthesise the so-called catacholamines that are essential for bowel health. You are unlikely to find them in the grocery store.

Take home

The take home from the authors is as follows.

  • Use more olive oil in our cooking; it is neutral in relation to the omegas.
  • Eat more foods containing omega-3 fatty acids; fish, freshly ground flaxseed and walnuts.
  • Avoid processed foods which generally contain large amounts of linoleic acid[4].

To which I would add:

  • At least on a weekly basis make sure we are enjoying unpasteurised probiotic foods such as kefir, sauerkraut and kimchi; yoghurt contains a limited range of these friendly bacterial.


kefir bubbling in funnel

Kefir is probably the simplest probiotic to make in the home kitchen, containing over 30 species of friendly bacteria, yeast cells and viruses. It takes about five minutes.

Kefir breakfast smoothieA kefir breakfast smoothie

Linoleic acid in sunflower and soybean oil promote inflammation

Linoleic acid in sunflower and soybean oil promotes inflammation by altering the omega-6 to 3 ratio.

This is known to increase the likelihood of us suffering from one of the inflammatory bowel syndromes; like Crohn's Disease and ulcerative colitis.

Do not confuse it with linolenic acid; that is a very beneficial omega-3 fat found predominantly in plants.

Its full name is alpha linolenic-acid, or ALA for short.


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