Omega-3 and Omega-6: a Delicate Balance

Omega-3 and Omega-6: a Delicate Balance


It’s time to understand now why it is so
important to make a distinction, within the polyunsaturated fatty acids, between the omega-6
and the omega-3 families. Although their structural functions which
we already discussed are very similar, their regulatory role as precursors of the eicosanoids
is very different. Remember that the eicosanoids are important
hormone-like substances that orchestrate many vital metabolic processes at the cardiovascular,
immune, and nervous system level. The main classes of eicosanoids are prostaglandins,
prostacyclins, thromboxanes and leukotriens. We can build all these molecules both from
omega-6 and from omega-3 fatty acids, and these molecules will affect the same areas
of metabolsim, but in different ways. Every cell in our body makes eicosanoids.
Their complex biochemistry is often challenging to understand, because for every molecule
in this group that does something, there is another that does the exact opposite. To complicate
things even more, both molecules are potentially useful, but both are potentially dangerous.
I know it sounds like the riddle of the sphinx, but let me make a couple examples to clarify
what I mean. There are some eicosanoids, called thromboxanes,
that promote platelet aggregation and blood clotting, and then there are others, called
prostacyclins, that instead inhibit platelet aggregation and promote blood fluidity. Which
is the good, and which is the bad? If we consider that formation of clots in the bloodstream
can sometimes trigger a heart attack, the eicosanoids that inhibit clotting could be
considered the good guys, since they keep our blood fluid. But on the other end, even
a little cut on our finger would cause us to bleed to death if it wasn’t for the eicosanoids
that promote platelet aggregation and clotting to close the wound. Prostacyclins also promote vasodilation in
our arteries, while thromboxanes, guess what, promote vasoconstriction. Excessive vasoconstriction
causes high blood pressure and cardiovascular risk, but on the other hand excessive vasodilation
would cause a dangerous blood pressure drop to the point of fainting.
Some eicosanoids promote immune function, some other depress it. Well, you may think,
this one’s easy. The good ones are those that promote immunity, to help us fight viruses,
bacteria and cancer cells. Well, it depends. If it wasn’t for their counterparts that
slow down this immune defense drive, this could go overboard resulting in autoimmune
disease, in which our overstimulated immune systems starts attacking the healthy cells
of our own body. Some eicosanoids have pro-inflammatory activity,
and needless to say, some other are anti-inflammatory. Inflammation is definitely something we’d
prefer to live without, it causes us pain, fever, and production of free radicals that
damage our tissues and accelerate the aging process and risk for chronic disease. However,
when it comes to fighting pathogens that attack our body, it is precisely the inflammatory
response what we need to get rid of these enemies as soon as possible. Some eicosanoids promote pain transmission,
other suppress it. Nobody likes to suffer, and the reason we take aspirin when our head
aches is precisely to block the production of this pain promoting eicosanoids. But on
the other hand, pain is a life-saving mechanism that enables us to realize that something’s
wrong so that we can take the necessary action. If we touch a very hot surface, we immediately
remove our hand to avoid a serious burn. If we feel a strong pain in our chest, we can
run to the hospital and save us from a heart attack. As you probably know, those individuals
that for genetic defect cannot feel any pain, usually die within their first years of life. Some eicosanoids promote cell proliferation,
some other inhibit it. Controlled cell proliferation is necessary so that our body can grow, develop
and repair damaged tissues. But if cell proliferation hadn’t a check, the risk for tumor development
and growth would be much higher. Some prostaglandins promote mucus and bicarbonate
secretion in our stomach, protecting it from acid corrosion that may lead to ulcers. However,
an excessive buffering of stomach acidity would impair its primary physiologic function,
which is helping food digestion and at the same time killing the vast majority of potential
pathogens that come with it. I think you got the idea. Now these opposite
actions are often performed by omega-6 derived eicosanoids and omega-3 derived ones. They
way I picture this is sort of a pulling-rope game, with the omega-3 team at one end of
the rope and the omega-6 team at the other. The omega-6 teams pulls toward inflammation,
platelet aggregation, vasoconstriction, pain transmission and strong immunity, the omega-3
teams pulls toward anti-inflammation, blood fluidity, vasodilation, pain suppression and
immunosuppression. We don’t really want any of the two teams
to win, because any of their effects brought to the extreme would be bad. What we want
instead is a balance between the two. We want a little bit of both and we should get both
of them from diet in appropriate proportions. The ideal omega-3 to omega-6 ratio is between
1:2 and 1:4, meaning that for every 2 to 4 grams of omega-6 in our diet, we want at least
1 gram of omega-3. Unfortunately the average US diet is far from this ideal ratio, and
we tend to have way too many omega-6 compared to the omega-3, promoting blood clotting,
inflammation, and hypertension.

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