The Effect of Quality and Quantity of Dietary Fat on the Immune System

Abstract

The effect of the quality and quantity of dietary fats on the morphology and function of the immune system of Sprague-Dawley rats fed either 5% mixed fat, 24% saturated fat, 24% polyunsaturated fat, or 24% partially saturated fat was examined. After 2.5 months of dietary treatment high fat groups showed evidence of splenic hyperplasia, however, no consistent morphologic changes were seen in the mesenteric lymph nodes (MLN). Splenocytes from rats fed the 24% polyunsaturated fat diet were cultured in fetal bovine serum (FBS) and had a depressed lymphocyte transformation response, which persisted after 5 months of dietary treatment. Supplementing the culture medium with 10% rat serum altered the transformation response profile, but high fat serum did not have an immunosuppressive effect. MLN lymphocytes from rats fed the 24% partially saturated diet for 2.5 months had an enhanced response to concanavalin A; at five months the response was elevated in the groups fed saturated as well as partially saturated fat diets. These results suggest that the modulating effect of fat on the immune system depends on the duration of feeding, the type of fat consumed and the organ examined.

Arachidonic acid supplementation enhances synthesis of eicosanoids without suppressing immune functions in young healthy men

“…Studies conducted in cultured cells and animal models show that n-6 polyunsaturated fatty acids (PUFA) inhibit immune cell functions (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). The results from studies in humans are mixed.…”

Training and natural immunity: effects of diets rich in fat or carbohydrate

“…Several studies indicate that fat-rich diets or obesity are associated with impaired immune function, whereas lowfat-diets improve immune function (Barone et al 1989; Table 1 The eect of training, independent of diet, on natural killer (NK)-cell activity (%), either unstimulated, or interleukin (IL-2)-or interferon (IFN)-a-stimulated, and blood mononuclear cell subpopulations, in n = 20 subjects. Data are given as the mean (SEM) Erickson et al 1980;Kelly et al 1989;Locniskar et al 1983;McHugh et al 1977;Nieman et al 1999;Stallone 1994). However, the impact of fat type is currently less clear (Rasmussen et al 1994).…”

“…Similar ®ndings were reported by the same group in a study including 42 elderly females (Nieman et al 1993). It has recently been concluded that although research data on humans are limited, obesity does appear to be associated with impaired immune function (Stallone 1994), and several studies tend to show that immune function is enhanced by a low-fat diet (Barone et al 1989;Erickson et al 1980;Kelly et al 1989;Locniskar et al 1983;McHugh et al 1977). Thus, the ®ndings on NK-cell activity and training are controversial, and it is possible that the increased NK-cell activity reported to occur in some groups of athletes is not directly related to training, but is dependent upon other lifestyle factors, such as diet.…”

Influence of Diets Containing Olive Oil, Sunflower Oil or Hydrogenated Coconut Oil on the Immune Response of Mice.

“…Previous studies have reported that diets containing oils or fatty acids added to the culture medium have strong effects on lymphocyte functions, in both animals and humans [1][2][3][4]. Polyunsaturated fatty acids (PUFA) such as (n-3) PUFA suppressed mitogen-stimulated proliferation of lymphocytes isolated from lymph nodes [ 1 ] and spleen of rats [ 5 ] , as well as from spleen of mice [ 5 ] and peripheral blood mononuclear cells from humans [4].…”

“…Previous studies have shown that fatty acids are involved in the modification of lymphocyte proliferation in both humans and animals [2,6,24], IL-2 synthesis [25,26], NK cell activity [11] and antigen presentation [27] both in vitro and in vivo and that these changes depend on the type of dietary lipid and the age of the experimental animals [28]. The results presented in this paper show that the supply of diets containing olive oil may increase the lymphocyte proliferation, although at the end of dietary supplementation the values decreased and these were very similar to those obtained at the beginning of the dietary supplementation, whereas IL-2 production was reduced except at the end of dietary administration where we have observed a significant increase with regard to the values obtained from the other groups.…”