Emulsion droplet crystallinity does not affect postprandial plasma lipopolysaccharide-mediated inflammation: Secondary analysis of a randomized double-blind crossover study in healthy men

High fat meals are considered to elevate chronic disease risk factors partially via their effects on absorption of bacterial lipopolysaccharide from the gastrointestinal tract and the resulting inflammatory and atherogenic responses. The effect of lipid physical state was previously reported to alter the rate and extent of lipid digestion, which could alter these processes. However, the effect of triacylglycerol solid versus liquid state on inflammatory pathways has not been investigated, while controlling for meal composition. Evaluating these effects could enhance the understanding of how saturated fat consumption contributes to health and/or disease. This randomized crossover study tested the impact of emulsion droplet crystallinity on postprandial plasma levels of endotoxin transporters (LBP and sCD14) and selected pro-inflammatory and atherogenic markers (TNF-α, CRP, IL-1β, IFN-γ, IL-6, sICAM, sVCAM, MCP-1/CCL2, PAI-1, and fibrinogen). Fasted healthy male participants (28 ± 5.5 y, 24.1 ± 2.6 kg/m2) consumed one of two emulsions (50 g palm stearin and 0.4% Span60 in water tempered to achieve either liquid or partially crystalline emulsion droplets at 37 °C) on two occasions. Plasma from blood samples at fasting and at 2-, 4-, and 6-hours post-meal was analyzed by immunoassays. Timepoint data were analyzed by two-way repeated measures ANOVA, while net incremental area under the curve (iAUC), log total AUC (tAUC), and log peak concentration after baseline (Cmax) were analyzed via paired t-tests. Sensitivity analyses were performed with one-way repeated measures ANCOVA for log tAUC and Cmax when baseline values differed significantly. Overall, no significant treatment effects were seen for any endpoint (P > 0.05). However, TNF-α, MCP-1/CCL2, PAI-1, and fibrinogen decreased significantly with time (P < 0.05), albeit with unclear implications. In conclusion, the results of this study did not support that emulsion droplet crystallinity significantly affects plasma endotoxin transporters nor lipid-mediated inflammatory and atherogenic processes during the postprandial phase.