Lipids (2) – Refined polyunsaturated fatty acids dangers:

“People should be informed of the dangers of consuming vegetable oils”

Dr. David M Diamond and Dr. Uffe Ravnskov

As we mentioned in the introduction of the lipids blogs, the oils and the fats we eat are a mixture of all three types of fatty acids (saturated, monounsaturated, and polyunsaturated) and depending on the type of lipid we consume, we could be radically changing the proportion of these.

For example, butter or coconut oil are basically composed of saturated fatty acids, olive oil of monounsaturated fatty acids and seed oils of polyunsaturated fatty acids.

Besides the controversy about the potential damage that may occur with high amounts of linoleic acid in the diet, based on science, the clear danger with lipids may be in consuming oxidized fatty acids, something that we will develop below. But first, let’s take a very brief look at the oxidation potential of each fatty acid.

Without going into too many details, the capacity of oxidation of a lipid depends on the amount of double bonds that their fatty acids have between their carbon atoms, since it is in that double bond where the oxygen gets in…

Saturated fatty acids have a form that does not allow oxygen to enter due to the lack of double bonds between their carbon atoms, which is why they resist oxidation very well:

(Butyric acid, eg from saturated fatty acid)

Monounsaturated acids have only one double bond:

(Oleic acid – ex. Monounsaturated fatty acid)

… and therefore, only one place where oxygen can enter, making them quite resistant to oxidation as well.

Polyunsaturated fatty acids, (ubiquitous in the modern diet), have two or more double bonds:

(Linoleic acid – ex. Polyunsaturated fatty acid)

… but this, instead of making them twice as susceptible as monounsaturated ones, makes them billions of times more sensitive to reacting with oxygen, something that gives them the potential to generate a cascade of free radicals.

Reactive oxygen species in the right amount have a physiological role (1), but abnormal amounts, are involved in all diseases (2) and every molecule that comes in contact with them becomes dysfunctional or toxic.

The oxidative damage that these oils may suffer in their natural state is delayed by the antioxidants contained in the seeds, but once refined and deprived of all protection, this changes dramatically.

Standard refinement involves heat, hexane (a component of gasoline), deodorization, and bleaching.

Once bottled, they potentially have a great deal of oxidation, but as if that wasn’t enough, they are used for cooking.

Exposure to heat multiplies the oxidation of the oil, the oxidation of the food that is cooked in it and the oxidation of the organism that consumes it.

(Note: I leave to the reader’s imagination, the potential oxidation that restaurant frying oil can have, which in most places is reheated multiple times.)

More studies:

In the animal model, the more polyunsaturated fatty acids they consume, the shorter their life span (3).
High amounts of linoleic acid produce ataxia and neuroinflammation in animals (4)
High amounts of linoleic acid is related to obesity and abnormal development in humans (4,5,6,7),
The delicate polyunsaturated fatty acids can become toxic compounds (8). This means that all refined vegetable oils and all products that contain them (most processed foods) can contain trans fats and oxidized fatty acids.
Chemical analyzes show that some polyunsaturated vegetable oils contain up to 5% trans fats, cyclic hydrocarbons and oxyphytosterols (9), which are carcinogenic and cause arterial damage.
Elevated 4-Hydroxynonenal (4-HNE) formation is related to many dysfunctions including cardiovascular and neurodegenerative diseases (10).

4-HNE is a product of lipid peroxidation, it can be endogenously synthesized following consumption of dietary linoleic acid and is present in heated vegetable oils (11). Actually, when the formation of 4-HNE were quantitatively assessed by RP-HPLC, 4-HNE was detected in all polyunsaturated vegetable oils tested (12) regardless of heating temperature.

In another study, sunflower oil exhibited the highest quantities of 4-HNE (13)
Polyunsaturated fatty acids have the potential to inhibit the production of prostacyclin (14), which is essential for blood to flow properly, increasing the possibility of clotting that can lead to heart disease.
Once they are part of cell membranes, polyunsaturated fatty acids react with oxygen producing peroxyl radicals, the primary free radicals in lipid peroxidation (15), changing the fluidity of the cell membrane and its function.
Polyunsaturated fatty acids generate compounds like acrylamide and cyclic aldehydes with the potential of mutating DNA (16), a central factor in health and longevity.
Polyunsaturated fatty acids can oxidize LDL (17), a known risk factor for heart disease.
13-HPODE, the most common dietary peroxidized lipid formed from the oxidation of polyunsaturated fatty acid, has demonstrated pro-inflammatory activity in a variety of immune cells and may produce intestinal inflammation (18).

And what about margarine?

Margarine used to be a calorie-dense and easy-to-carry solid, composed of an oily substance extracted from pressing animal fats blocks and dried milk, which was originally created in France by Hippolyte Mèges-Mouries to feed Napoleon’s troops.

Made in this way, it was a healthy substance, but shortly after selling his patent to a Norwegian company called Jurgens, Margarine came to the US.

Once in America, it underwent transformations until decades later, they found a much cheaper way to make a similar product by hydrogenating seed oils.

This version, unlike the one created by Hippolyte Mege-Mourie, didn’t have any nutritional value and was a source of trans fats and oxidized fatty acids.

Margarine today:

It is incredible that this dangerous substance, whose atherogenic capacity has been known since the 50′ (19), has been recommended as the “healthy alternative” to butter.

In 2013, thanks to almost six decades of warnings from lipid scientists such as Dr Fred Kummerow (19) and Dr Mary Enig (20), the dangers have become more popular (although many still remain in the shadows).

This persuaded governments to take action on trans fats, so manufacturers had to figure out how to make margarines without hydrogenation in order to minimize the content of these harmful fats.

The new process is called interesterification and even if this successfully reduces the trans-fat content, it is still a potentially dangerous industrial process.

Interesterification is obtained in two ways.

One is through enzymes that produce interesterified fats and the other involves chemical catalysts, product neutralization (to remove the caustic catalyst), bleaching and deodorization. But whatever the method, it is still a highly industrialized process whose end result will contain degradation products full of free radicals, chemical residues and hexanes (21).

In addition, the new versions of Margarine continue to contain refined oils, so that in their total composition, there is still a great oxidation potential.

As if that were not enough, many contain interesterified soybean oil, which is linked to glucose intolerance, weight gain, and increased stress markers in the liver (22).

Luckily, the science below will tell us that there is no reason to be looking for a man-made alternative substance when nature gave us the wonderful gift of butter.

In fact, many experts recommend a good consumption of this delicious fat (23), since apart from having vitamins A, E and B12, thanks to its content of vitamin K2, conjugated linoleic acid and butyrate; it can have anti-inflammatory properties, improve digestive health and potentially prevent heart disease, osteoporosis, and cancer (24,25,26,27,28,29,30,31,32).

(Note: These properties are present at their optimal levels in butter made from organic milk from grazing cows, and may vary according to the process and origin of the raw material.)

So, according to what we know, which vegetable oils should we choose?

One of the potential dangers lies in the sensitivity of polyunsaturated fatty acids to oxidation, so the best options seems to be virgin vegetable oils (from fruits, not seeds) with a different composition.

Two examples of this are coconut oil and olive oil since these lipids are rich in saturated and monounsaturated fatty acids respectively, so they resist oxidation while preserving their properties.

Other options could be the virgin versions of avocado oil, almond oil or walnut oil, but I would use them only as a dressing, since because of their richness in polyunsaturated fatty acids, it does not seem to be a good idea to expose them to high temperatures.

(TakeAway: While fats and oils rich in saturated and monounsaturated fatty acids such as butter, extra virgin coconut oil or extra virgin olive oil are stable, the oils of conventional use (sunflower, corn, etc.) are mostly composed of by unstable refined polyunsaturated fatty acids. These fatty acids can be easily oxidized and potentially become toxic compounds, contain trans fats, 4-HNE and 13-HPODE, increase coagulation, produce free radicals, alter cell membranes, collaborate with fatty liver, atherosclerosis and other dysfunctions.)

In the next blogs we are going to analyze how the idea of saturated fat arose and if we should stop consuming this fats,