Hi David, the following is an excerpt of a post I sent to another
list, a mini review of "Traditional Foods Are Your Best Medicine"
(Dr. Ronald Schmid) that tackled the issue of quality fats and their
sources:

[quote]
One chapter on essential fatty acids and eicosapentaenoic acid (EPA)
includes a revealing metabolic pathway diagram (p77) that outlines
the various food sources' fatty acid precursors and their conversion
to the omega series of prostaglandins. Looking at this chart, it's
become clearer to me how a diet based on vitamin and mineral
deficient produce (or self-induced stress, lack of exercise,
sunshine, etc) can severely limit the ability of the body to form the
omega-3 variety. Although plant sources such as linseed oil contain
the needed precursors, cold-water fish oils provide EPA which can be
directly converted thus eliminating potential bottlenecks that may be
encountered from alpha-linoleic acid (a precursor) to EPA. It's all a
bit too detailed to explain in words but the diagram lays it out
nicely. From this chapter alone, I think I have a better feel for why
raw pasture-fed beef and wild salmon helped to rebuild my health so
dramatically.
[end quote]

Here's also an article describing the prostaglandin pathway:

http://www.westonaprice.org/facts_about_fats/tripping.html

About half way, the paragraph starting with "Carnivorous animals lack
both...." describes the need by certain populations to procure long
chain fatty acids from food sources directly since they lack the
enzymes necessary to elaborate them.

Maybe, genetically I'm similar to one of these groups. ;)

Cheers,
Jo

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