Adherence to the Mediterranean Diet and Circulating Levels of Sirtuin 4 in Obese Subjects
Adherence to the Mediterranean Diet and Circulating Levels of Sirtuin 4 in Obese Subjects
The Mediterranean diet (MD), a healthy dietary pattern based on some common dietary
 characteristics in Mediterranean countries, is associated with high antioxidant capacity
 linked to the low saturated fat intake that might contribute to reduce free fatty acid (FFA)
 availability and oxidation in mitochondria, thus reducing the production of the reactive
 oxygen species (ROS) superoxide, and promoting cellular health. To assess the adherence to
 the MD, a simple 14-item questionnaire had been tested in different settings by the PREDIMED
 (PREvención con DIeta MEDiterránea) multicenter, randomized, primary prevention trial. On the
 other hand, to allow a more an accurate measurement of the actual macro and micronutrient
 intakes, including dietary anti-oxidant micronutrients, the 7-day food records is considered
 as the "gold standard" of self-administered food frequency questionnaires.

 Circulating levels of Sirtuin 4 (Sirt4), part of a complex of proteins that control diverse
 biological processes, including lipid metabolism, are low in obese patients, as a possible
 attempt to decrease fat oxidative capacity and mitochondrial ROS production, however
 promoting ectopic liver fat storage.

 The phase angle (PA), a measure determined by bioelectrical impedance analysis (BIA), and the
 visceral adiposity index (VAI), a gender-specific mathematical index based on simple
 anthropometric and metabolic parameters, represent well-validated, reliable and widely used
 markers of cellular health and ectopic adipose distribution and function, respectively. The
 fatty liver index (FLI) is a surrogate measure for fatty liver recently proposed as an
 independent predictor for diabetes mellitus.

 Aim of the present study was to investigate in adult obese individuals the levels of Sirt4
 according to the adherence to the MD evaluated by PREDIMED questionnaire, focusing on the
 possible association with single dietary components evaluated by 7-day food records, and to
 evaluate the association between circulating levels of Sirt4 and PA, as marker of cellular
 health, VAI, as index of adipocyte dysfunction, and FLI, as a predictor of fatty liver.
Inclusion Criteria:

 -  Adult obese subjects

 Exclusion Criteria:

 -  Hypocaloric diet in the last three months or specific nutritional regimens, including
 vegan or vegetarian diets;

 -  Presence of liver or renal failure, cancer, and acute or chronic inflammatory diseases
 based on a complete medical examination and laboratory investigations (psoriasis,
 rheumatoid arthritis and chronic obstructive pulmonary disease);

 -  Occasional or current of use of drugs affecting β-oxidation, including non-steroidal
 anti-inflammatory drugs, α-lipoic acid, valproic acid

 -  Use of weight loss medication or lipid-lowering drugs

 -  Altered thyroid hormone function tests or thyroid hormone treatment or altered
 somatotropic axis

 -  Alcohol abuse according to the Diagnostic and Statistical Manual of Mental Disorders
 (DSM)-V diagnostic criteria

 -  Vitamin/mineral or antioxidant supplementation

 -  Subjects dropped out from the study since they refused to undergo full
 laboratory-instrumental examinations.