*3.1. Dietary Saturated Fatty Acids Acutely Increase Serum GM-CSF Levels in the Postprandial State of Healthy Volunteers*

Serum from healthy volunteers was collected at fasting (TG concentration 0.42±0.1 mmol/L) and at the postprandial hypertriglyceridemic peak (1–3 h) after SFA-enriched (TG concentration 1.54 ± 0.4 mmol/L), MUFA-enriched (TG concentration 0.65 ± 0.2 mmol/L), or PUFA-enriched (TG concentration 0.63 ± 0.2 mmol/L) meal ingestion. As depicted in Figure 1a, only the meal rich in SFAs postprandially increased serum GM-CSF levels when compared to the other fatty acid-enriched and no-fat meals. Thus, the total area under the curve (AUCTOTAL) values for serum GM-CSF were significantly higher (*p* = 0.0170) only after the ingestion of the high-fat meal enriched in SFAs in healthy volunteers (Figure 1b). Interestingly, serum GM-CSF levels, which is a DC maturation factor, were acutely increased by the SFA-enriched meal at the postprandial hypertriglyceridemic peak, suggesting that dietary fatty acids present in TRLs modulate the DC maturation process. In addition, serum TG correlated with the levels of serum GM-CSF in healthy volunteers (*R*<sup>2</sup> 0.9977, *p* = 0.0308, Figure 1c).

**Figure 1.** (**a**) Serum granulocyte/macrophage colony-stimulating factor (GM-CSF) levels at fasting and at the postprandial period after the administration of a control meal (with no fat) or high-fat meals enriched in saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) or MUFAs + omega-3 long-chain polyunsaturated fatty acids (PUFAs) in healthy subjects. (**b**) Area under the curve of serum GM-CSF during postprandial period in response to test meals. (**c**) Correlation between postprandial serum GM-CSF levels and serum triglycerides (TGs) in healthy subjects after administration of test meals. Values are presented as means ± SD (*n* = 6).
