Dietary supplementation with ω-3-polyunsaturated fatty acids decreases mononuclear cell proliferation and interleukin-1β content but not monokine secretion in healthy and insulin-dependent diabetic individuals

The effects of dietary supplementation with omega-3-polyunsaturated fatty acids (omega-3-PUFA) on the proliferative response of PBMC and on the secretion of monokines and arachidonic acid metabolites from PBMC and monocytes (Mo) from healthy subjects and patients with recent-onset insulin-dependent diabetes mellitus (IDDM) were examined. Three groups of eight to nine healthy individuals were randomized to either 2.0 g/day or 4.0 g/day of omega-3-PUFA devoid of vitamins A and D, or an isocaloric amount of placebo. Furthermore, eight patients with recent-onset IDDM received 4.0 g/day of omega-3-PUFA. IL-1 beta production and TNF-alpha secretion was determined before and after 7 weeks of treatment, and 10 weeks after withdrawal of treatment. Significant increases in platelet and PBMC membrane eicosapentaenoic acid was found in omega-3-PUFA-treated individuals. omega-3-PUFA treatment significantly reduced the content of IL-1 beta in lysates of PBMC, but did not affect PBMC or Mo secretion of IL-1 beta, TNF-alpha or prostaglandin E2 (PGE2) or PBMC leukotriene B4 (LTB4) secretion in healthy subjects or in IDDM patients. A significant inhibition of the PHA-stimulated, but not the spontaneous or PPD-stimulated, proliferative response of PBMC was observed in healthy and diabetic subjects treated with omega-3-PUFA. No correlation was found between PHA-stimulated PBMC proliferation and PBMC secretion of TNF-alpha and IL-1 beta. There were no significant differences in the spontaneous or the PPD- or PHA-stimulated proliferative responses of PBMC between diabetic and healthy individuals at entry. We conclude that although dietary supplementation with 4.0 g/day of omega-3-PUFA inhibits the proliferation of PBMC and reduces IL-1 beta immunoreactivity in PBMC and Mo, it does not alter monokine, PGE2 or LTB4, secretion in healthy or IDDM subjects.