*2.2. Blood Collection*

Venous blood (10 mL) samples were collected after overnight fasting using S-Monovette® 4.9 mL and a Clotting Activator/Serum blood collection system (Sarstedt, Nümbrecht, Germany). Serum was obtained by centrifugation (at 2000× *g*, 10 min) and stored at −80 ◦C for later analyses (but no longer than a six-month period). No hemolysis was observed in any of the samples.

### *2.3. Fatty Acids Assay*

Serum samples were thawed and a mixture of chloroform/methanol (2:1 *v*/*v*) was added to a 50-μL aliquot. Samples were flushed with nitrogen gas and stored at 4 ◦C. The next step was to perform double extraction. After drying, lipids (in lower phase) were saponified (using a mixture of KOH and methanol) and subsequently methylated by boron trifluoride (14%). The analysis was carried out using gas chromatography–mass spectrometry (GC/MS) (Shimadzu GC-2010 PLUS gas chromatograph coupled to a Shimadzu QP2010 Ultra mass spectrometer (Shim-pol, Warsaw, Poland)). Compounds were separated on a fused-silica capillary column SPTM-2560 (100 m, 0.25 mm inner diameter (i.d.)) with a film thickness of 0.20 mm (Supelco, Darmstadt, Germany). The injection volume was 1.0 μL, and the temperature of the injection port was 230 ◦C with a split ratio of 1:20, while helium was used as a carrier gas; the temperature program was 70 ◦C/2 min, 175 ◦C/25 min, and 200 ◦C/17 min. As done by other authors, non-endogenous C17:0 free fatty acid (5 μg of 1 mg/mL stock) was used as an internal standard [16].
