Wednesday, April 12, 2006

Of fish and evolution

Just for kicks, I was following up on a statement I heard on Discovery Channel - and considering the recent news of the missing land-sea species link makes this even more pertinent perhaps - so was doing some well-rounded reading and came upon these gems.

To preface, I’m pretty passionate about this because it has really changed my life for the better. Something simple that when consistently and sufficiently done greatly influences one’s well-being, mental acuity, and physiological health.

An angle that probably doesn’t get a lot of airplay and thus not a lot of people know about is that Omega 3 fatty acids (e.g. fish oils) were/are crucial to human evolution, particularly for the significant growth of the frontal lobe of the hominid brain.

Regardless of how fish has been bastardized these days by modern marketing thus so negatively perceived as something for health nuts, over fished, or tainted by our man-caused mercury contamination - though smaller, cold-water fish like salmon is still clean so far - good ol’ common sense should apply today, however unsexy it may be (or you can get ultra-pure molecularly distilled fish oil capsules at Costco, which at 6 cents a softgel is a bargain insurance policy of sorts).

So I present to you, the reader, an academic paper outlining DHA’s role in evolving the hominid brain (DHA is a primary form of Omega 3’s) as well as the importance of Homo Sapien's close proximity to land-water masses. A pretty nice, readable bedtime piece or you can just skim the abstract :) ...
Evidence for the Unique Function of Docosahexaenoic Acid (DHA) During the Evolution of the Modern Hominid Brain

The African savanna ecosystem of the large mammals and primates was associated with a dramatic decline in relative brain capacity. This reduction happened to be associated with a decline in docosahexaenoic acid (DHA) from the food chain. DHA is required for brain structures and growth. The biochemistry implies that the expansion of the human brain required a plentiful source of preformed DHA.

The richest source of DHA is the marine food chain while the savannah environment offers very little of it. Consequently H.sapiens could not have evolved on the savannahs. Recent fossil evidence indicates that the lacustrine and marine food chain was being extensively exploited at the time cerebral expansion took place and suggests the alternative that the transition from the archaic to modern humans took place at the land/water interface. Contemporary data on tropical lake shore dwellers reaffirms the above view.

Lacustrine habitats provide nutritional support for the vascular system, the development of which would have been a prerequisite for cerebral expansion. Both arachidonic acid (AA) and DHA would have been freely available from such habitats providing the double stimulus of preformed acyl components for the developing blood vessels and brain.
We suggest that the evolution of the large human brain depended on a rich source of DHA from the land/water interface. We review a number of proposals for the possible influence of DHA on physical properties of the brain that are essential for its function.