Good Eicosanoids - Bad Eicosanoids

Definition and Functions

What are eicosanoids?

Eicosanoids are biological agents that regulate many organic functions. They belong to this category:

• Prostaglandins
• Prostaciciline
• lipoxins
• thromboxanes
• Leukotriene.

What functions do they perform?

They perform many functions and for this reason they are also known as superhormones .

On the other hand, these effects are often universally opposed

This is why in medicine it is used to differentiate them summarily into "good" and "bad" eicosanoids .

Eicosanoids modulate:

• The cardiovascular system
• Blood clotting
• Renal function
• The immune response
• inflammation
• Numerous other functions.

What do fats have to do with eicosanoids?

For many years now there has been much talk of essential fatty acids, emphasizing their importance in promoting the synthesis of good eicosanoids at the expense of bad ones.

It is worth underlining again that the distinction between good and bad eicosanoids is a forcing, since both have decisive functions for the organism.

Importance of Eicosanoids

All eicosanoids are crucial for the body

We examine the biological role of prostaglandins, a group of eicosanoids capable of regulating the inflammatory response.

When the organism is attacked by biological agents (bacteria, viruses, etc.), physical (trauma, heat, UV rays) or chemical (acids, etc.), it defends itself, giving rise to the so-called inflammatory response.

This is a rather complex event, where many mediators participate, including bad eicosanoids (which, as we will see, are not so "perfidious").

Bad prostaglandins and acute inflammation

In the early stages, which characterize the so-called acute inflammation, the bad eicosanoids, in particular the PGE2 prostaglandins, act above all.

Thanks to the action of these eicosanoids, in the area attacked the vessels dilate and increase their permeability, favoring the passage of leukocytes (white blood cells) into the inflammation site.

At this point the white blood cells can, depending on the case, incorporate the damaging agents, kill the bacteria, degrade necrotic tissue, foreign agents etc., allowing the body to restore the conditions prior to aggression.

Good prostaglandins and acute inflammation

To restore the conditions prior to inflammation it is necessary for the white blood cells to release other types of eicosanoids, or good ones.

These are the anti-inflammatory prostaglandins PGE1, PGI2 and PG3.

If this did not happen the inflammation would persist and become chronic.

Chronic inflammation

This condition is recorded, for example:

• In persistent infections
• In autoimmune diseases (rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, rectal ulcerative colitis, psoriasis, etc.)
• Intoxication or poisoning by some exogenous toxic substances (silica, asbestos, foreign bodies)
• In the excessive permanence of certain endogenous substances (gastric acid).

Chronic inflammation can cause significant damage to the tissue affected by this process, due to the intense proliferation and activity of some cells responsible for destroying the invaders.

Other eicosanoids that participate in inflammation

Prostaglandins are not the only eicosanoids involved in this series of events, involving, for example, also thromboxanes (TX) and leukotrienes (LT).

After a general view of the inflammatory process, we can therefore make the classic distinction between good eicosanoids (inhibit the inflammatory process) and bad eicosanoids (promote inflammation).

Eicosanoids and Diet

Is there a diet capable of intervening on inflammation?

Since essential fatty acids are precursors of eicosanoids, we have tried to study an optimal dietary regime to favor the balance between molecules with pro- and anti-inflammatory action.

This research has given rise - among other things - to the principles of the so-called zone diet.

It must be said, however, that the metabolic pathways leading to the synthesis of the various eicosanoids are rather complex, integrated and therefore promiscuous. It is therefore reasonable to think that trying to control them only with the diet is at least optimistic.

What fats are responsible for producing bad eicosanoids?

From a general point of view, the "bad" eicosanoids derive from arachidonic acid (AA), a fatty acid present in animal fats.

Arachidonic acid is also produced from linoleic acid (LA) which is contained in numerous seed oils.

Sources of essential fatty acids or essential seeds omega 6

The omega 6 are mainly found in foods of vegetable origin. in particular in the seeds or oils extracted from: salicornia, safflower, evening primrose, poppy, grapes, sunflower, prickly pear, hemp, corn, wheat germ, cotton, soy, walnut, sesame, rice bran, argan, pistachio, peanuts, peach, almond, canola, flax, olive, palm, cocoa, macadamia, coconut etc.

The exception is arachidonic acid, which abounds mainly in products of animal origin such as: egg yolk, lard, butter, chicken, bovine, etc.

For the avoidance of doubt, we recall that linoleic acid is an essential fatty acid; it is the progenitor and precursor of all the essential seeds omega 6, among which there are also various molecules destined to the production of good eicosanoids (for example GLA gamma linolenic acid).

The semi essential omega 6s are:

• Gamma Linolenic Acid (GLA): it is a substrate from which the body produces some good anti-inflammatory eicosanoids
• Diomo-Gamma-Linolenic Acid (DGLA): its functions are still little known.
• Arachidonic acid (AA): it is the one produced with less effectiveness by LA, but it represents a substrate for pro-inflammatory eicosanoids.

Moreover, it is good to repeat it, to certain eicosanoids the adjective "bad" can be attributed only if present in non physiological and excessive concentrations.

Through the sequential activity of the elongases and desaturases (two enzymes involved in the metabolic processes of all essential fatty acids) linoleic acid is converted into arachidonic acid, which as we have seen has a pro-inflammatory action.

However, recent data show that this conversion is inefficient in vivo.

Moreover, the metabolic levels of arachidonic acid are subject to a fine regulation, which is largely independent of the dietary intake of LA, but could instead be influenced by the direct intake of arachidonic acid with the diet.

Not by chance, the pro-inflammatory activity of omega 6 (although widely theorized and demonstrated in vitro) does not seem to find unequivocal confirmation in the in vivo studies carried out on humans.

What fats are responsible for producing good eicosanoids?

Although good anti-inflammatory eicosanoids can also originate from certain omega-6s, the safest and most effective source is the essential or semi-essential omega-3s.

These are:

• Alpha linolenic acid (ALA): frankly essential as well as a precursor of the two essential seeds; it is considered metabolically less active than its derivatives
• Eicosapentaenoic acid (EPA): essential seed, it is the main substrate from which the body produces good anti-inflammatory eicosanoids
• Docosahexaenoic acid (DHA): essential seeds, it has many functions, among which the composition of nervous and ocular tissue seems to be dominant.

Sources of essential fatty acids or essential seeds omega 3

Most plant-based foods used as a source of essential lipids contain both omega 6 and omega 3, although in proportions almost always favorable for omega 6.

Foods that contain high levels of omega 3 are on average lacking in the western diet.

The best sources of omega 3 are those that contain the two essential seeds EPA and DHA: blue fish (mackerel, sardine, bonito, lanzardo, aguglia etc.), fish from the cold seas (salmon, etc.), other fishery products (molluscs and crustaceans ), krill, algae and related oils (of salmon, cod liver, krill, algae).

They are less important because they contain ALA (biologically less active) and omega 6, vegetable sources such as seeds and oils extracted from: chia, kiwi, perilla, flax, cranberry, camellia, porcelain, sea buckthorn, hemp, walnut, canola and soy.

The omega 3 also hinder the synthesis of prostaglandins deriving from arachidonic acid, promoting, in addition to the already mentioned increase in good eicosanoids, also a decrease in the bad ones.

To promote the right balance between good and bad eicosanoids the ratio between omega 3 and omega 6 in the diet should be at least 1: 6 (the most recent studies suggest trying to reach values ​​between 1: 2 and 1: 4), in the face of the current tendency to exceed 1: 10 (typical value of western industrialized countries).

To rebalance this ratio it is essential to increase the consumption of fish, especially the blue one and the species that populate the northern seas, or to use specific food supplements such as krill oil, seaweed oil, salmon and cod liver oil.