MODULATION OF CYTOKINE PRODUCTION IN-VIVO BY DIETARY ESSENTIAL FATTY-ACIDS IN PATIENTS WITH COLORECTAL-CANCER

1. The effects of essential fatty acids (gamma-linolenic acid, eicosap entaenoic acid, docosahexaenoic acid), at a dose of 4.8 g/day, given i n combination as dietary supplements, on cytokine production were inve stigated in patients with colorectal cancer. 2. Total serum cytokines - interleukin (interleukin-1 beta, 2, 4 and 6), tumour necrosis factor -alpha and interferon-gamma - were analysed using the enzyme-linked im munosorbent assay technique at different time intervals during the cou rse of essential fatty acid supplementation. 3. Fatty acid uptake and patient compliance were confirmed by a significant increase in serum l evels of gamma-linolenic acid, eicosapentaenoic acid and docosahexaeno ic acid in all three fractions: triacylglycerol, cholesterol and phosp holipid. 4. There was no significant alteration in total serum cytokin e concentration/levels in the first 2 months of essential fatty acid i ngestion, but the levels of serum cytokines steadily declined thereaft er, reaching minimum levels after 6 months of essential fatty acid sup plementation. 5. Essential fatty acids, at the dose and duration (6 mo nths) used in this study, reduced total serum interleukin-1 beta level s by 61% (P=0.044), interleukin-2 by 63% (P=0.05), interleukin-4 by 69 % (P=0.025), interleukin-6 by 83% (P=0.030), tumour necrosis factor-a by 73% (P=0.040) and interferon-gamma by 67% (P=0.050). 6. Three month s after cessation of essential fatty acid intake, however, these cytok ine levels returned to presupplementation values. 7. This present stud y has shown that long-term n - 3 and n - 6 EFA ingestion results in a significant reduction in circulating key cytokines. The precise mechan ism of this reduction is unclear.