Amadeus wrote:

>"My conclusion would be that DHA is not a limiting factor to
>brain growth, except in diseased states like intoxication with
>tFA, alcohol, excess w-6 acids, high insulin."

Todd said:
>I think I agree with this.  There are people all around us, with
>normal-sized brains and great intelligence who are the products
>of a diet in which om-3 fats are quite scarce.  They don't eat
>fish; they don't eat veggies; they don't eat flax oil; etc.
>Whatever om-3 fat they get must come from the tiny amounts in
>grain-fed meats and grain-based foods.  I'm not arguing, of
>course, that this is a good thing, but it suggests that our
>bodies greedily harvest every bit of om-3 from our food and
>utilize it pretty well.

Recall, however, that in the last 35000 years human brain size has in fact
decreased by 11%. Most of that decrease (8% of the 11%) has come in just
the last 10000 years. This is a significant decrease in a very short period
of evolutionary time. Thus while people these days may seemingly appear to
be maintaining brain size (the observation appears anecdotal to me, I'd
like to see some support), it would be so only up to a point and only in
the short run, since the historical evidence says otherwise.

Granted, the human species has gone through much cultural flowering and
technological/scientific advance over 10000 years, so there is obviously
still a large quota of intelligence in the human brain even given that it
is 11% smaller now. How much additional intelligence might we demonstrate,
however, if our brains were growing to their full potential?

What is noteworthy about the brain size decrease over the last 35000 years
is that not only has it come during a time period when DHA consumption has
decreased considerably, but when starch consumption has gone to an all-time
high for humans due to the agricultural revolution of the last 10000 years.
This evidence flies directly in the face of the tuber (starch) hypothesis
for brain size evolution on both the DHA issue and the starch issue at the
same time.

For info/refs on this point, see:

http://www.beyondveg.com/nicholson-w/hb/hb-interview1f.shtml#brain-gut%20conn'n%
201

http://www.beyondveg.com/billings-t/comp-anat/comp-anat-4b.shtml#brain%20size%20
decr

Herb