Effect of an isoenergetic traditional Mediterranean diet on the high-density lipoprotein proteome in men with the metabolic syndrome.

Background/aims: The objective of this preliminary study was to examine the impact of the Mediterranean diet (MedDiet) on the high-density lipoprotein (HDL) proteome in men with the metabolic syndrome (MetS).

Methods: Twenty-six men with the MetS first consumed a standardized baseline North American isoenergetic control diet (5 weeks) and then consumed an isoenergetic MedDiet (5 weeks), both in full feeding condition. The HDL fraction was isolated by ultracentrifugation at the end of each diet and the HDL proteome assessed by isobaric tags for relative and absolute quantitation and mass spectrometry.

Results: Of all proteins identified within HDL, only 3 showed significant changes in relative abundance after the MedDiet versus the control diet, including a reduction in inflammation-related inter-α-trypsin inhibitor heavy chain H4 (fold change: 0.62) and hemoglobin subunits α (fold change: 0.40) and β (fold change: 0.46). Other HDL-bound proteins associated with functions related to lipid metabolism/cholesterol homeostasis, oxidation, coagulation, complement activation and immunity were unchanged after consumption of the MedDiet for 5 weeks.

Conclusions: Changes in the HDL proteome may explain, at least partly, the well-known anti-inflammatory effect ascribed to the MedDiet. Otherwise, short-term consumption of the MedDiet seems to have little impact on other features of the HDL proteome in men with the MetS.