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The ''Truth'' about Omega 3 and Omega 6 fatty acids


Wednesday, March 13 2002 - Filed under: General

Dear All
This will undoubtedly expose my ignorance but I am having a very hard time with all the push on omega-3 fatty acids.
I expect some of the experts on these listserves to help us all out and not keep hitting us with words we do not understand.
First off, the word ''omega'' is Greek for the last letter of the alphabet, viz ''alpha to omega.''
That means that among all the different kinds of fatty acids (the triglyceride fats in our diet) the carbons which can go up to 20) are lined up in a chain and when we hear omega, we should know that we are talking about the last carbon in the chain.
So, as a biochemist, I am looking at the chains of carbons in linolenic acid (omega-3) and linoleic acid (omega-6).. All that means that in both of these chains of 18 carbons in each chain, if we count from the last carbon, a double bond (unsaturated carbons) appears after carbon 3 in linolenic (omega-3) and after carbon 6 in linoleic (omega-6).

Now, Dr. Mercola and his followers makes this kind of statement:
<Omega-3 Fatty acids are essential fatty acids, necessary from conception through pregnancy and infancy and, undoubtedly, throughout life.


The ratio of omega-6 to omega-3 fatty acids has increased in industrialized societies because of increased consumption of vegetable oils rich in omega-6 fatty acids, ie, linoleic acid, and reduced consumption of foods rich in omega-3 fatty acids.>



What he is saying is that the omega-6's (linoleic) are not that good for us and should be reduced.

It is no wonder that I have been confused because I have studied fat biochemistry and we were not taught this way (and I am not talking about what I was taught in nutrition but in basic biochemistry)

This is one sentence in my very best nutrition text by Pike and Brown, Nutrition: An Integrated Approach,

The polyunsaturated acids, linolenic, linoleic, and archidonic, have often been designated the essential fatty acids (needed because the body cannot make them), although current practice is to consider only linoleic acid as significant in human dietary needs.

I am going into this because I have always been terribly confused by alternative medicines big hype on diets too high in linoleic which has always looked at as a good guy fatty acid.

I also have been taught that one must, if using fats like vegetable oils (and I use sunflower) that we should be sure to eat foods with sufficient vitamin E (like our nuts) or take a supplement in order to prevent the double bonds in vegetable oils from breaking (double bonds are weak bonds) and can easily break in cell membranes and form free radicles (sp?)

I would like to have a debate on some of this hype on ratios of omega 6 to omega 3. C'mon Debbie, C'mon Paul Idol.

Response from Seth

You opened this up for debate, so here it goes:

Omega-6 (n-6) and Omega-3 (n-3) are both essential PUFAs
(polyunsaturated fatty acids) which are subject to oxidation.
If you are consuming high amounts of either one of these, it would be
wise to take Vitamin E along with it to help protect these fatty
acids from oxidizing and forming free radicals, etc.

These fatty acids, n-6 and n-3, are deemed essential because the body
cannot make them on their own.
The n-6 fatty acids are converted into eicosanoids ( ie
prostaglandins, prostacyclins, leukotrienes, and thromboxanes) that
increase inflammation, constrict blood vessels, and encourage blood
clotting.
The n-3 fatty acids are converted into eicosanoids that reduce
inflammation, dilate blood vessels, and inhibit blood clotting.

Now the story goes that a long long time ago (during the Paleolithic
era), the diet of humankind consisted
of a 1:1 ratio of these n-3 and n-6 fatty acids. Therefore our bodies
are genetically ready for a balance of these fats. However, in the
last 100 years, the ''modern'' diet has been bombarded with n-6 oils
and receives very little n-3 oils.
(The current ratio is like 45:1, n-6 to n-3). This, apparently, leads
to all kinds of inflammatory problems: arthritis, heart disease,
crohn's disease, high blood pressure, etc.

The reason that n-3's are such big news now-a-days starts out with
the Inuit (Eskimo). The Inuit traditionally ate a high percentage of
meat and fat. Researchers couldn't believe that these guys weren't
falling over from heart disease, diabetes, etc. So they tried to
figure out the ''protective'' factor that kept the Inuit healthy. They
concluded that it must be the n-3 fatty acids. They also looked at
various cultures (ie Mediterranean diet) and found that diets high in
n-3 seemed to be protective against these diseases of modern man.

Now here is my take.
We know that Omega-3's are converted into eicosanoids that ease
inflammation.
So it is no wonder that n-3 has been shown to help these disease of
inflammation ( the Crohn's disease - fish oil studies).
However, I do not think that this imbalance of fatty acids is the
cause of these disease. The body does not just get inflammed for no
reason. It must be in response to something. There is a casual
relationship showing some bacterial infections with coronary heart
disease. So it is no wonder that the body is getting inflammed if it
has a chronic infection.
My take is that n-3 is not what protected the Inuit from disease, but
that their entire diet did. They were not eating sugars and starches
that pathogenic bacteria like to eat. So they were not infested with
bacteria - so they had no trigger for inflammation to begin with.
People now think that n-6's are bad fats and n-3's are good fats. But
n-6's play a critical role and without inflammation, we would be
suffering from other diseases.

PUFAs have also been shown to inhibit the thyroid. So it would be
wise to minimize both n-3 and n-6 if you are having thryoid problems
and/or need to lose weight. Saturated fats do not inhibit thyroid
function and have been unfairly criticized as causing diseases. There
are a large number of cultures that consumed high amounts of
saturated fats and did not have the disease that we do today.
Saturated fats also are not as easily oxidized as PUFAs.

How's that for starters?

Seth

Response from Marj
>How's that for starters?

Very nice summary. I tend to agree with your assessment that it is
probably not the omega-3s that are so healthful for the Inuit. Ray Peat
wrote an article that began by discussing a western researcher who ate a
diet of what HE thought was a typical Inuit diet - high levels of whale
blubber. The guy ended up with lots of problems. Peat's conclusion is
that the guy ignored/forgot the fact that the Inuit ate the ENTIRE animal -
not just the flesh meat parts - including organ meats, glands, etc. I
believe that one must eat things like organ meats, etc. in order to balance
minerals in this type of a diet. Otherwise, the Inuit diet would be highly
imbalanced for zinc, copper, magnesium, and manganese.

Just my $.02,





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