The word “eicosanoid” often appears on my web page, so I will explain it briefly.

In simple terms, “Eicosanoid” is the final substance produced in the cell membrane from essential fatty acids, and has 20 carbon atoms in the skeleton that acts like a powerful hormone in and around the cell. (In Greek, eikosi means 20). Therefore, it can be said that it is a local hormone.

Unsaturated fatty acids of omega 3 (ω3) and omega 6 (ω6) are closely related to the production of eicosanoids. Omega 3 and omega 6 are classified according to the position of the carbon double bond constituting the unsaturated fatty acid. However, the explanation is too technical and will be omitted here.

Just as insulin and glucagon, which are hormones involved in sugar metabolism, regulate blood sugar while acting oppositely, numerous eicosanoids take on their roles and antagonize, responding to the micro environmental adjustment of neighboring cells and tissues at the cellular level without interruption.

I classify many eicosanoids as malignant ones with an effect that promotes inflammation and as benign ones with an anti-inflammatory effect. It’s a very rough way of classifying, but here I give priority to easy understanding. The brief summary is as follows:

Effects of benign eicosanoids:

Anti-inflammation, vasodilation, platelet aggregation suppression, immune system enhancement, cancer suppression, allergy symptom relief.

Effects of malignant eicosanoids:

Anti-inflammation, vasodilation,  promotion of platelet aggregation, decrease immune system, allergic symptoms.

For example, prostaglandin E1 classified as a benign eicosanoid has platelet aggregation suppression effect and vasodilatory effect, and prevents hypertension and cardiovascular diseases, while thromboxane A2 classified as a malignant eicosanoid has a vasoconstrictive effect and platelet aggregation effect. Because of these two effects thromboxane A2 is prone to induce heart and vascular diseases.

But we need malignant eicosanoids, too. For example, when the finger is inadvertently injured, bleeding will not stop if thromboxane A2 does not have a vasoconstrictive or platelet aggregation promoting effect.
Also, if only the benign eicosanoid prostaglandin E1 is present in excess, blood pressure is unnecessarily lowered and we are in shock. However, we don’t hurt any part of the body every day, and usually the vasoconstrictive effect of thromboxane A2 is not so much needed, and instead it is easy to cause high blood pressure, myocardial infarction, etc. Therefore it is categorized as a malignant eicosanoid.
But in the case of a battle, malignant eicosanoids are more advantageous. In order to win the battle, at the moment of the battle the blood pressure should be high and the chance of getting a wound is high, so the blood must be easy to clot.
Benign eicosanoids and malignant eicosanoids are just like sympathetic and parasympathetic nerves. Both are necessary. But in our daily life if malignant eicosanoids dominate benign eicosanoids, we will get sick. Hypertension, myocardial infarction, cerebral infarction, lupus, asthma, arthritis, psoriasis, and even cancer are closely related to malignant eicosanoids. If defined at the cell membrane level, disease can be said to be an imbalance of eicosanoids or chronical domination of malignant eicosanoids over benign eicosanoids.

Benign and malignant eicosanoids are metabolized from both ω3-unsaturated fatty acid and ω6-unsaturated fatty acid. But malignant eicosanoids metabolized from arachidonic acid from ω6 have stronger effects than malignant eicosanoids from ω3 (for example, TXA3 <TXA2). And leukotrienes such as LTB4, LTC4, LTD4, and LTE4 are also metabolized from arachidonic acid, which are highly active malignant eicosanoids that are deeply involved in allergies. In particular, LTC4, LTD4, and LTE4 are said to be 100 to 1000 times more powerful than histamine.
In addition, PG3 and TA3 from EPA metabolized from ω3-unsaturated fatty acid prevent ω6-unsaturated fatty from being metabolized to arachidonic acid. Therefore EPA increases benign eicosanoids as a whole.

Alpha-linolenic acid belongs to ω3-unsaturated fatty acid. And linoleic acid belongs to ω6-unsaturated fatty acid. (Please pay attention to the difference, “LINOLENIC” and “LINOLEIC”.
Often confused). Therefore taking foods that contain α-linolenic acid a lot promote our health. Flaxseed oil (perilla oil, sacha inch oil) are abundant in α-linolenic acid. Fish (Krill) contains EPA/DHA which are ω3-unsaturated fatty acids. And animal meat contains lot of linoleic acid.

Simple Summary

Fish (Krill) → EPA/DHA → benign eicosanoids
Flaxseed oil → α-linolenic acid → benign eicosanoids
Animal meat → linoleic acid → arachidonic acid → malignant eicosanoids


Vegetable oils such as safflower oil, sunflower oil, corn oil, rapeseed oil, soybean oil, cotton seed oil, sesame oil, peanut oil, wheat germ oil, evening primrose oil, grape seed oil are abundant in linoleic acid. Therefore please don’t take them often.

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