Wednesday, June 30, 2010

Fish as brain food helped homo become sapiens?

Fish as brain food helped homo become sapiens?

What gave rise to the rapid brain size increase that made us ‘thinking' men? The answer: we began eating fish

One of the puzzles in biology is how rapid the human brain developed.

It took hardly a million or so years for us to become the “thinking man” or homo sapiensfrom our immediate ancestors and cousins, the homo habilis, erectusorrudolfensis. How do we know this?

From a comparison of the brain to body ratio. While the other homoshad a brain volume of 600-800 ml (based on skull size), we have about 1250 ml, and all for roughly the same body size.

Thus, we have far more within our head than our immediate ancestors or the chimpanzees (brain about 410 ml).



A recent paper by Dr. David Braun and colleagues in the June 1, 2010 issue of the Proceedings of the National Academy of Sciences, USA, reports on the historical evidence of a large collection of fish bones near a putative settlement of homo, dated to about 1.95 million years ago, in the Rift Valley of Africa. This is the area from where we humans are thought to have originated.

And the fish bones they found had bite marks matching those of human (and not great ape) teeth.

Why is this paper important? For this, may I refer you to an excellent review article by Drs. C L Broadhurst, S.C. Cunnane and M A Crawford that appeared 12 years ago in the British Journal of Nutrition (1998; 79:3-21), a review that reminds us of the logic of Sherlock Holmes?


Also note that fish contain those vital nutrients that the brain needs in order to develop and grow. The human brain is “oily”, containing as much as 600g of lipid per kg, with long chain fatty acids like arachidonic acid (AA) docosa-hexenoic acid (DHA), that the body does not produce; they are thus “essential nutrients” – and fish have them in good measure.

So then, where do vegetarians get their essential lipids from?

From green vegetables, walnuts and peanuts, sesame and mustard, cotton, sunflower and other oil sources. And this is why modern-day nutritionists insist on our intake of poly-unsaturated fatty acids (PUFA), rather then Dalda or trans-fats.


Note too that meat (pork, beef, chicken and such) is muscle or protein-rich. The fat content meat has is not the type that feeds the brain. It is, as my granddaughter Kimaya says, “body food” while nuts, fish or greens are “brain food”. Thus in having chanced upon eating fish, homos had struck the jackpot, in comparison to the largely veggie primates or the carnivorous animals in the neighborhood.


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