The brain, genes, fish oils and folic acid

The mammalian central nervous system is a very complicated system, with an array of different cell types each with its singular morphology , connections and function. The phenotypic properties of each cell are the product of combinations of expressed gene products peculiar to that cell type. The Allen brain atlas project ( is studying the genetic structural and cellular architecture of the mouse brain. A mammoth undertaking using complex techniques. There are approximately 20,000 expressed genes in the adult mouse brain. The project looks at genes with regional expression patterns allowing descriptions for functional similarities across the 12 major brain regions.
Classical definitions of brain regions is based upon a combination of overall morphology, cellular cytoarchitecture, ontological development and functional connections. Such studies offer insights into brain structure and function, and may also challenge our definitions of brain structure which are anatomical and to an extent functional.
Lein et al 2007, Nature Jan 11, vol 445 pp 168-176

However these genes can only effectively express themselves if they have substrates to work with. The foetal brain grows rapidly during gestation ,weighs 350g (of which 50% is lipid ) at birth and triples in weight during the first two years of life. The lipids are predominantly polyunsaturated long chain fatty acids , some of which are essential fatty acids. .These are derived from preformed fatty acids or precursors. Of the fatty acids docosahexaenoic and arachidonic acids are the most important. Much of which is obtained from the diet.
It would appear that eating fish results in better neurological development than when the mother has a poor or absent fish intake.
This raises two questions. Fish contain small amounts of unwanted contaminants e.g. methylmercury, and possible toxicity problems for the foetus. .
And raises the irreverent thought, should Eskimos be the cleverest people on earth.
Lancet vol 369, February 17th, pp537-8 ; and Hibbeln et al Lancet , vol 369. pp 578-85
Flippancy apart this is very important observation

At the other end of life the brain begins to loose cognitive function, largely expressed as failing memory. The elderly with low serum folate and raised homocysteine concentrations are at risk of reduced cognitive function. In a large double blind randomised placebo controlled clinical trial in the Netherlands it was shown that taking 800 ųg of folic acid a day significantly improved cognitive memory. Again nutrition affecting a complex system.
Durga et al Lancet 2007, vol 369, pp 208-16

We Nutritionists live in a world which generates a fantastic array of scientific advances especially in molecular biology which appear to make nutrition less relevant. Perhaps we should see this as a great opportunity to clarify many of the mysteries of nutrition and health.

Martin Eastwood
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