Dairy Fat Consumptions Do Not Modulate Immune Functions in a Swine Model of Insulin Resistance: A Preliminary Analysis

Abstract

ObjectivesBiomarkers of full-fat dairy consumption have been inversely associated with variables of insulin resistance (IR) and immune function. To understand the effect of consuming dairy fat per se on immune function in the context of IR, we used our established low birthweight (LBW) swine model of high fat diet induced IR to compare regular fat dairy products vs. low-fat dairy products and compared to a control high fat diet (CHF). We hypothesize that consuming a diet rich in dairy fat will improve immune function in the context of IR. MethodsAt 5 weeks of age, LBW piglets were randomized to consume one of the 3 experimental diets: 1) CHF, 2) HF supplemented with 3 servings high fat dairy (HFDairy) and 3) HF supplemented with 3 servings low fat dairy (LFDairy). As comparison groups, normal birthweight (NBW) piglets were fed a CHF or standard pig grower diet (Chow). A total of 35 pigs (LBW-CHF n = 8, LBW-HFDairy n = 8, LBW-LFDairy n = 8, NBW-CHF n = 6, NBW-Chow n = 5) were fed for 7 weeks. At 12 weeks of age, pigs were euthanized for tissue and blood collections. Mitogen stimulations on peripheral blood mononuclear cells were conducted to assess immune responses. ResultsResults show that there were no statistical differences in IL-2, IL-10 and TNF-α levels after pokeweed mitogen (PWM, T and antigen presenting cell mitogen) and phytohaemagglutinin (PHA, T cell mitogen) stimulations between all LBW groups. However, IL-10 levels after PHA stimulation were found to be higher in NBW-Chow compared to LBW-CHF, LBW-HFDairy and LBW-LFDairy (all P < 0.05). Similarly, IL-2 levels after PWM stimulation were found to be higher in NBW-Chow compared to LBW-CHF and LBW-HFDairy (both P < 0.05) groups but not LBW-LFDairy. ConclusionsCurrent data suggest that consumption of dairy products, regardless of the fat content, as little effect on immune function in the context of IR. However, we demonstrated that diet-induced IR piglets exhibit altered immune responses to a T cells mitogen, compared to NBW piglets. Funding SourcesAgriculture Funding Consortium, NSERC Discovery Program, Dairy Farmers of Canada-Nutrition Research Program.