Karen wrote:
>
><<A recent study ('98 I believe), showed that the ALA in flax (and other
>plant
>sources) are very poorly converted to the bioavailable EPA and DHA.
>(something like 6 % and 1 % respectively). The enzyme responsible for the
>conversion may be affected by the following factors: presence of Omega-6
>oils in the diet; deficiencies of magnesium, zinc, and B6; and presence of
>trans-fats in the diet.>>

Deficiencies of magnesium, zinc, and B6 will do *a lot* of damage, not only
slow down the d6d enzyme.

A blocked d6d enzyme will not only decrease the DHA/EPA generated, but most
important (IMO) block eicosanoid production (from w-6 fats).

You seem to count only on EPA/DHA as benefit from w-3 fats.
There are some more purposes for the original ALA.
The use in cell membranes for exapmle.
And they are as fats more easily fuelled than more saturated ones.

Thinking paleolithically (what was eaten/available then), just look how much
ALA is in nature fats of plants and animals.
I recall something about 1/3 to 1/4 of all fats beeing PUFA (few exceptions
in a few plants)
And ratios with w-6 excess only in certain plant fats (nuts).
2.paleopoint: Was DHA/EPA eaten by paleolithic humans?
I mean from 2mio years back, up to neolithicum?
The only source worth to mention would be brains... (no cold water fish)

On Wed, 13 Jun 2001 08:47:17 -0400, siobhan <[log in to unmask]> wrote:

>**  This is true.  The presence of high levels of saturated,
>monounsaturated, trans-fst, and cholesterol will inhibit conversion of ALA
>to EPA.
>
> The conversion of ALA to EPA relies upon adequate levels of B3, B6, C,
>Magnesium and Zinc to fuel the action of the D6 desaturase enzyme (this
>action of this enzyme is required for conversion).

And all that would block also the conversion of LA to eicosanoids...

Amadeus