EFFECT OF DIET AND PLASMA FATTY-ACID COMPOSITION ON IMMUNE STATUS IN ELDERLY MEN

The relationship between fatty acids in plasma and basal (B), interleu kin-2-(IL-2), and interferon-alpha (IFN-alpha)-stimulated natural kill er (NK) cell activity was studied in healthy elderly men aged on avera ge 70.5 y (65-81 y). B-NK correlated significantly with the fraction o f plasma fatty acids consisting of total polyunsaturated fatty acids ( PUFAs), total n-6 fatty acids, and linoleic acid (r = -0.68, r = -0.62 , and r = -0.52, respectively). Significant negative correlations were also found between IFN-alpha stimulated NK cells and the three groups of fatty acids and between IL-2-stimulated NK cells and PUFAs. Likewi se, negative correlations between PUFAs in the diet and BNK, IL-2, and IFN-alpha stimulated NK cell activity were found. The number of NK ce lls increased significantly but NK cell activity did not change after 5 wk on a diet lower in fat but higher in PUFAs than the subjects' hab itual diet. It is concluded that the amount and type of dietary fatty acids influence in vitro measures of immune function in elderly men. F rom an immunological point of view, a high intake of n-6 PUFAs may be inadvisable.