Abstract
Acoording to the length of the chain of the fatty acids, we distinguish short chain fatty acids (SCFA) with 2 - 5 carbons in the chain, medium chain fatty acids (MCFA) with 6 to 11 carbons, long chain fatty acids (LCFA) with 12 to 21 carbons - sometimes those with 22 C are also counted, and very long chain fatty acids (VLCFA) with more than 22 carbons in the chain. Moreover, according to the number of double bonds present in side chains fatty acids can be classified as saturated FAs (SFAs, no double bonds), monounsaturated FAs (MUFAs, a single double bond), and polyunsaturated FAs (PUFAs, >= 2 double bonds).
All these FAs play different roles in the pathophysiology of the brain. The spectrum of fatty acids found in the brain is different from the composition of FA in plasma lipids, in adipocytes of adipose tissue and other tissues.
About 50 - 60 % of the dry matter of the adult human brain consists of lipids. Of this, about 35 % are long-chain fatty acids among which arachidonic acid and docosahexaenoic acid predominate.
In the fat of the frontal cortex of people who died at the age of 25 - 45, McNamara and Carlson found 36 % SFAs, where stearic acid and palmitic acid were represented almost exclusively. The share of total PUFA n-6 was 17 % (predominantly arachidonic acids) and the share of total PUFA n-3 was about 14 % (practically only docosahexaenoic acid).
MUFA n-9 fatty acids were represented by 20 % (virtually only oleic acid). Saturated and monounsaturated FAs can be synthesized de novo in the brain, while PUFAs enter the brain mainly from the bloodstream.
The diverse roles of all abovementioned fatty acids in the pathophysiology of the brain are described in the work.