[Effect of polyunsaturated fatty acids on immune status: importance as structural and mediator building blocks]

A review of pharmacodynamic effects induced by polyunsaturated fatty acids (PUFA) with special emphasis on their significance as components of biomembranes and as precursors for mediator formation.

Original papers as well as review articles in German and English were retrieved by repeated MEDLINE research.

Pertinent original papers as well as review articles since 1983 as well as some significant original papers of earlier origin were used.

The current classification of different groups of fatty acids, due to their degree of desaturation, implies that various classes of fatty acids can be correlated to either energetic or structural or functional tasks, respectively. PUFAs are an integral part of membrane structures and serve as precursors of mediator synthesis. They are therefore prone to have major impact on cell function. In particular, interactions between PUFAs and the immune system are substantially determined by the effects of different eicosanoids, which are also derived from PUFAs. However, their impact on various immune functions is dose dependent as well as quantitatively different. If the immune response mediated by eicosanoids is under consideration, actions on the specific immune system have to be discriminated from effects on nonspecific immunity.

During homeostasis, PUFAs as well as their derived mediators are important factors for a well-operating immune system. If, however, eicosanoid synthesis becomes either diminished or augmented, functions related to the specific immune response are impaired. By contrast, the intensity of the nonspecific immune response is strongly related to the amount of mediators released. During nutritional therapy, lipids not only provide an energetic source but also interfere with structural integrity and functional performance of the cell.