Don Matesz wrote:
>Amadeus Schmidt <amadeus–GMX.DE> wrote:
>>
>>But I *don't* think that brain eating or DHA eating was essential
>>to having large and functional brains, IMO not.
>>Otherwise we would have lost the metabolic capability
>>to build it up ourselves from precursors, just like cats lost it.

>Well the evidence is that we do not have the ability to produce
>DHA ourselves AT THE RA REQUIRED FOR PROPER DEVELOPMENT AND
>MAINTENANCE OF THE BRAIN.  The point is that an ani may have the
>ability to produce some DHA but not enough to meet all needs or
>achieve proper development or health.

I heard and read the claims that the EFA systhesis capability of
humans wasn't "enough". The references are a few studies
considering the syntheses rate "not enough". But how could we (or they)
judge the synthesis rate correctly? Compared to what?
Additionally, the body synthesizing its own enzymes and stuff
is a cybernetic process. With a regulating mechanism such as
availability of precursors and need/shortage signals.
The synthesis rate may vary to big extents therefore.

The other point: if DHA was so abundant in the real paleolithic food
(may it be brain or marrow or mussle) the body might have
discarded his EFA synthesis metabolism. Just like he did it
by the abundance of Vitamin C.
But he kept the synthesizing capability, and i think if he kept it
he will have kept it in the adequate and necessary quality.
So, luckily all the people short on brain polyunsaturated fats
(DHA) survive with a normally well funtionating brain.
And this applies more to meatatarians as for vegetarians IMO.
Because most of the first group (when not paleo thinking) most
exately leave out brain and marrow. And many leave out fish.
Many vegetarians are concious about PUFA fats. But most I know
consume predominately w-6 fat donators (like sunflower)
And aren't concious about w-3 fats.

>It is estimated that under the best circumstances humans require at
>least 100 molecules ALA to make one molecule of DHA (see Smart Fats by
>Michael Schmidt, Ph.D.).
And how many molekules of DHA are really used up per day?
(The count of antioxidants may determine the usage rate)
And how many grams flax or hemp oil provide that much
molekules times 100?

>And it has been shown repeatedly that vegetarians have much lower
>DHA levels than is optimal.  "In a study of the blood levels of
>long chain fatty acids of vegetarians, doctorsw found that DHA
>levels were very low, especially in long-term vegetarians.
We already discussed the DHA-veggie child study, you mention it
and i see no new argument here.
Especially I still miss an explanation why there was a much higher
difference in DHA between british and US meatatarians,
as comparing meatatarians (tuttivore) to  vegetarians.
I still suspect hydrogenated fats or an oversupply of w-6 fats
as responsible.

We're not discussing vegetarianism, are we?
Both groups (veggies or not) have their disadvantages of supply.
Even if someone decides to be a vegan for some reason
(or, like me paleo-oriented vegetarian)
then he or she may easily decide to get additional DHA
(as well as b12) from supplements.
From cultivated microorganisms that produce the
DHA (and B12) anyway - may it go through a fish/cow or not.

>
>>Neolithic trading ...
>>>But fish go bad ...
>... we know that primitive
>diets have included "rotten" fish, that is what fermented fish
>sauces are ...
Romans did that. One of their favourite souces was from fermented
fish. Its transportation needs 1.Pottery 2.a kind of cart
3.horses. Neolithics were the first who had pottery.
I still doubt that linearband imported fish. They had flax.

>>Nets and fishooks are a recent invention only about 40kyears old.
>We don't need nets and fish hooks to catch fish,
>and certainly not to get shellfish, fish roe, tiny new fish, etc.  I
>recall Hans reporting he caught a fish with his hands and ate it alive
>not too long ago.
We don't need the nets/hooks for occasionally lucky or difficult
catches. But to catch then in quantity IMO requires them.
Catches by spears and hand catches (like Hans') are most ever only
in sweet water (rivers or lakes with a bank nearby).
But sweet water fish aren't the good DHA donators.

If nutrition would have had effects on human bodies'
specializations, big quantities (like fish from nets)
would be necessary IMO.
But i think its opposite: first comes the spezialization
then there may be additional needs of nutrition.
And additional brain needs at first more carbohydrates and nerve
vitamins, then PUFAs too. I think thats a founded POV.

regards
Amadeus

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