LONDON: Scientists have uncovered the secret of mankind’s soaring intellect — fish. Thanks to our predilection for cockles and mussels, shrimps and the odd bit of cod, our chimp-brained ancestors were transformed into a species so smart it now rules the Earth.
This startling idea was outlined at a recent evolutionary conference when neurochemists, nutritionalists, anthropologists and archaeologists gathered to debate current research on the origins of humans’ big brains, and concluded that we got our head at the seaside.
‘A shore-based diet was essential for the evolution of human brains,’ Professor Stephen Cunnane of Toronto University told the annual meeting of the American Association of Physical Anthropologists.
The fish theory also provides evolutionary backing for studies that have suggested that even today the consumption of fish food supplements can help people with modern problems. For example, one recent project has shown they help children with dyslexia, hyperactivity and even autism.
On the other hand, the theory flatly contradicts several other hypotheses that have been put forward to explain our brains’ evolution. Some say that climate catastrophes which triggered droughts and forest fires forced early humans to develop flexible, adaptive minds. Others say our adoption of a carnivore lifestyle provided us with a rich source of energy that fuelled our crania’s expansion; while for some it was our love of high-protein foods such as nuts, roots and tubers, such as potatoes.
But these ideas both contain crucial flaws, say fish theory supporters: in particular, neither can explain how mankind supplied itself with a plentiful supply of omega fatty acids, chemicals that are crucial to brain development and which are found in significant amounts in fish and shellfish but are scarce in other foods, even meat.
In particular, two fatty acids — docosahexaenic acid (DHA) and arachidonic acid (AA) — make up almost 60 per cent of the brain’s structural material, the former being vital for the development of neuron membranes, the latter for the construction of blood vessels in the brain.
“We may think we are clever,” declared Professor Michael Crawford, of the Institute of Brain Chemistry at North London University. “However, we
Both DHA and AA — which are found primarily in fish — are passed through placentas and breast milk, so that offspring of the first primitive men and women who opted for a life on the shore were provided with the essential components that ensured brain growth.
In effect, our access to seafood created a biological loop. We ate more and more seafood, got smarter, and thought up ever more cunning ways to obtain seafood. However, as Leigh Broadhurst, of the US Department of Agriculture, said: ‘It was the diet that came first.’
It is not clear, however, when mankind first took to the shore to bolster its brainpower with the odd winkle or crab. Some researchers argue that the process began five or six million years ago when the human lineage first split from that of the apes.
Others believe that the process was much more recent. Anthropologist Alison Brooks, of George Washington University, told the journal Science that the best direct evidence for the emergence of our fish preferences are recent: middens of shellfish and fishbones left by Homo sapiens 100,000 years ago, and elaborately carved fishing spears dated at around 90,000 years old.
It could have been the adoption of a seashore life at this time that propelled Homo sapiens to intellectual greatness, while our rivals the Neanderthals became extinct.
Even today infants who are deprived of these fatty acids grow up to suffer cognitive deficiency as well as attention deficit problems, while senile dementia and schizophrenia have also been linked to diets low in DHA and AA.—Dawn/The Observer News Service.