n6:n3 ratio


"From The Center for Genetics, Nutrition and Health, Washington, DC.

Human beings evolved consuming a diet that contained about equal
amounts of n-3 and n-6 essential fatty acids. Over the past
100-150 y there has been an enormous increase in the consumption
of n-6 fatty acids due to the increased intake of vegetable oils
from corn, sunflower seeds, safflower seeds, cottonseed, and
soybeans. Today, in Western diets, the ratio of n-6 to n-3 fatty
acids ranges from {approx}20-30:1 instead of the traditional
range of 1-2:1."

I have two major concerns with these statements.

First, the time scale. I'm old enough to well remember when lard,
suet and butter were replaced in Canada by margarines and
vegetable oils, and it was no 100-150 years ago, it was less than
60. For years after the introduction of margarine, the dairy
lobby made sure that it was illegal to sell any margarine here
unless it was yucky-looking white. (Later, it became legal to
include a dye packet. Margarines instantly became soft and were
packed in plastic bags so that all you had to do to have butter-
coloured margarine was to knead the unopened package.) I don't
remember when pre-coloured margarine became legal because I
couldn't stand the smell of early margarines, so always used
butter until I moved to Ottawa, where the large Italian
population ensured that fine olive oils were available.

Second, the reference population for 'traditional'. My mother's
family lived since 1818 over 100 miles from any significant fish-
bearing water. And, with transportation by farm horse and wagon
and with no refrigeration other than river ice, their consumption
of seafood was mighty close to zero. (No, they didn't use salted
fish - my mother never heard of it and my grandmother's recipe
box contains not a single mention of it.) They didn't grow flax,
they couldn't grow olives with the climate, so almost all their
lipids came from corn (maize), wheat, or grass-eating meat.
Before that, her family (including most of her in-laws) came from
the Alston Moor in England (see http://sankey.ws/wallacea.html),
where the diet would have been very similar for longer than we
have recorded history there, except that the primary grain would
have been barley. I don't believe they could have had anything
remotely close to an n6:n3 ratio of 2:1.

Personally, I aim for a maximum ratio of 4:1 and achieve it
easily, given the plentitude of fine fish resulting from air
transport and freezing (cf. http://sankey.ws/dietref.html). But,
I'm very uncomfortable with the claims made for 2:1, let alone
1:1, for my effective ancestry.
.