Analysis of the 2nd symposium "Anomalies of fatty acids, ageing and degenerating pathologies".

The second symposium on anomalies of fatty acids, ageing and degenerating pathologies for the French-speaking community was held during January 2002 in Paris (France) and reunited more than 200 participants, including a majority of medical practitioners. It was organised around 8 conferences treating the following subjects: a general presentation of the metabolism of fatty acids and their biological functions (in particular polyunsaturated fatty acids or PUFA), the exploration of PUFA in man during situations of nutritional and pathological disequilibrium, and the importance of PUFA in the aetiology and prevention of pathophysiologies such as cardiovascular, autoimmune and inflammatory diseases, diabetes and obesity, cancer and certain neuropsychiatric affections such as depression. Indeed, even though edible fatty acids present a common energetic function, by beta-oxidation, and a structural function, as a constituent of membrane lipids, some of them have a more specific role as an essential nutrient. These are essential fatty acids including the two families of polyunsaturated fatty acids (n-6 and n-3 PUFA). Their metabolism leads to the synthesis of derivatives found in cellular membranes (structural role) and oxygenated molecules, the eicosanoids, whose main action is of the same type as that of hormones. These derivatives and oxygenated molecules also regulate different metabolic pathways by modulating the expression of target genes via activation of specific transcription factors. Due to their quality and their quantity in food, the PUFA may interfere with the incidence of a large number of pathologies whose causes are varied (cardiovascular and inflammatory diseases, cancers, neuropathologies, ...). The particular interest in nutrition of PUFA of the n-3 series (or omega3) and in particular of long-chain derivatives mainly found in high quantity in fish oils (eicosapentaenoic acid and docosahexaenoic acid) is now widely confirmed for cardiovascular and inflammatory physiology and formed the subject of increasing investigations for prevention of certain pathologies of the central nervous system. In this paper, we are first going to recall the generalities of metabolism and functional properties of PUFA. Secondly, we will list the pathologies whose frequency and symptoms are susceptible to be corrected by the dietary intake of PUFA, notably by reaching the nutritional equilibrium between the family of linoleic acid (n-6 or omega6) and that of alpha-linolenic acid (n-3 or omega3).