EFFECT OF DIETARY OMEGA-3-FATTY-ACIDS ON CELL-MEDIATED CYTOTOXIC ACTIVITY IN BALB/C MICE

The effects of feeding a diet rich in omega-3 (n-3) fatty acids on immune cell prostaglandin production and cytotoxic activity before and after a viral challenge were studied in female BALB/c mice. Weanling mice were fed purified diets containing either 10% by weight corn oil (CO), 10% linseed oil (LO), or 8% menhaden oil+2% corn oil mix (FO) for 8-12 weeks. The LO diet provided 5.6 g/kg of 18:3n-3 and the FO diet 1.6 g/kg and 0.5 g/kg of 20:5n-3 and 22:6n-3, respectively. Natural killer (NK) cell activity in the unchallenged FO-fed mice was significantly lower than in CO-fed mice. Seven days after a viral challenge, cell-mediated cytotoxic (CMC) activity by splenocytes and peritoneal exudate cells from LO-fed mice was higher compared to CO and FO-fed mice. The feeding of n-3 rich diets significantly influenced the number of cells obtained from the spleen and peritoneum. Splenocyte prostaglandin E and F production was decreased by over 70% in both the LO and FO-fed, compared to CO-fed mice. The fatty acid profile of total lipids from serum and splenocytes reflected the relative n-6 and n-3 composition of the dietary fats. In summary, dietary n-3 fatty acids significantly influenced CMC activity of immune cells. Alterations in immune cell PG production do not seem to explain these differences in CMC activity. Changes in the fatty acid composition of immune cells may be an important factor. © 1990 Pergamon Press plc.