Effect of dietary supplementation with black currant seed oil on the immune response of healthy elderly subjects

Background: We have shown that the age-associated increase in prostaglandin E-2 production contributes to the decline in T cell-mediated function with age. Black currant seed oil (BCSO), rich in both gamma-linolenic (18:3n-6) and alpha-linolenic (18:3n-3) acids, has been shown to modulate membrane L ipid composition and eicosanoid production. Objective: Our objectives were to 1) test whether dietary supplementation w ith BCSO can improve the immune response of healthy elderly subjects, and 2 ) determine whether the altered immune response is mediated by a change in the factors closely associated with T cell activation. Design: A randomized, double-blind, placebo-controlled (soybean oil) study was conducted to examine the effect of 2 mo of BCSO supplementation on the immune response of 40 healthy subjects aged greater than or equal to 65 y. In vivo immune function was determined by delayed type hypersensitivity ski n response. Peripheral blood mononuclear cells (PBMCs) were tested for in v itro immune response. Results: In subjects supplemented with BCSO, the total diameter of indurati on at 24 h and individual responses to tetanus toroid and Trichophyton ment agrophytes were significantly higher than their baseline values. The change in response to tetanus toroid was significantly different from that of the placebo group. The BCSO group showed a significant increase in proliferati ve response of PBMCs to the T cell mitogen phytohemagglutinin that was not significantly different from that observed in the placebo group. BCSO had n o effect on concanavalin A-induced mitogenic response, interleukin 2 and -1 beta production, and PBMC membrane fluidity. Prostaglandin E-2 production was significantly reduced in the BCSO-supplemented group, and this change w as significantly different from that of the placebo group. Conclusion: BCSO has a moderate immune-enhancing effect attributable to its ability to reduce prostaglandin E-2 production.