The invention relates to an oil, fat and/or lecithin-based fat blend containing polyunsaturated fatty acids. The inventive fat blend is characterized in that the fatty acids gamma-linolenic, stearidonic acid and eicosapentaenoic together make up 10 to 500 mg/g total fatty acids. The gamma-linolenic and eicosapentaenoic acids each represent 20 to 50 wt. % and the stearidonic acid represents 15 to 50 wt. % of the sum of these three fatty acids. The inventive fat blend can be incorporated into a dietetic or a pharmaceutical product, especially a dietetic food, and can be used especially for administering to patients suffering from chronic/inflammatory diseases, disorders of the lipid metabolism, a weakened immune function and/or a restricted lipolytic capacity of the gastrointestinal tract.