Major advances have been made in understanding the biochemistry of essential fatty acids (FA) and their interactions with metabolic pathways leading to the production of longer and more complex fatty acids and lipids.

Less understood are the roles played by FA which are known to affect neurotransmitters, peptides, releasing factors, hormones, and a variety of physiological and cognitive processes.

Based on empirical findings we propose that
(a) FA exert a controlling function in the modulation of neuronal membrane fluidity, and
(b) the critical factor in FA action and efficacy is not absolute level but rather the ratio between various groups of FA.

This approach unifies the biochemical and cognitive results obtained from many different and unrelated fields of research.