EFFECT OF DIETARY N-3 N-6 FATTY-ACID RATIO ON THE TOTAL COUNT, FATTY-ACID COMPOSITION, AND HISTAMINE AND LEUKOTRIENE CONCENTRATIONS OF MAST-CELLS IN TUNICA MUCOSA BRONCHIORUM OF TYPE-I ALLERGIC GUINEA-PIG/

To search for the most effective dietary n-3/n-6 ratio to suppress the type I allergic response, we performed basic experiments that applied parameters associated with the type I allergy, Guinea pigs fed on die ts containing lipids with the n-3/n-6 ratio at different levels and th e polyunsaturated fatty acid/saturated fatty acid ratio of a fixed lev el were sensitized with ovalbumin and reared for two weeks, The lowest or critical level of the n-3/n-6 ratio which produced a significant d ifference in the parameters was as follows: about 2.0 for the response of mast cells and eosinophils; 0.5 and 1.0, respectively, for the upt ake of n-3 and n-6 polyunsaturated fatty acids and decreased histamine production; and 0.2 for decreased leukotriene B-4 and total leukotrie nes 4, and increased leukotrienes 5/leukotrienes 4, The critical level of the n-3/n-6 ratio thus differed widely according to the parameter, Overall, the upper limit for the dietary n-3/n-6 ratio to suppress an tigen-induced type I allergic responses is suggested to be around 1.0.