A Mediterranean Diet-Based Culinary Intervention in Adults With Metabolic Syndrome (CUINAMET)

Comparador Ativo: Grupo de controle

Comportamental: Standard nutritional counseling

Participants assigned to the control group will receive standard nutritional counseling in Mediterranean diet, consisting of three individual consultations at baseline, 3 months, and 6 months to monitor adherence to dietary recommendations. At each visit, health parameters will be assessed and questionnaires will be administered to evaluate dietary behavior and related outcomes.

At baseline, 3 months, and 6 months, participants will undergo the same measurements as the intervention group. After completion of the study, participants in the control group will be provided with the Mediterranean recipe booklet and access to the educational videos on Mediterranean culinary preparations used in the intervention group.

Experimental: Culinary-Nutritional Intervention Group

Comportamental: Mediterranean diet-based culinary intervention

Participants assigned to the culinary-nutritional intervention group will receive three individualized nutritional counseling sessions in Mediterranean diet, at baseline, 3 months, and 6 months, including health assessments and questionnaire administration at each visit. At the baseline visit, participants will receive a Mediterranean recipe booklet. Throughout the intervention, they will also receive educational videos featuring Mediterranean culinary preparations and cooking techniques.

In addition, participants will attend nine hands-on culinary medicine workshops over the 6-month intervention period. Workshops will be conducted every two weeks during the first 3 months (six workshops) and monthly during the last 3 months (three workshops). The workshops will focus on Mediterranean diet principles, healthy cooking skills, meal planning, food selection, and preparation of Mediterranean-style recipes to facilitate adherence to the dietary intervention.

Changes in metabolic syndrome components

Changes in metabolic syndrome components according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria, including waist circumference, blood pressure, fasting glucose, triglycerides, and HDL cholesterol, measured as continuous variables, using a score ranging from 1 to 5.

Body weight, fat mass and lean mass

Weight in kilograms (kg) using a calibrated electronic scale. Fat mass and lean mass in kilograms (kg) measured using dual-energy X-ray absorptiometry (DXA).

Body fat

Body fat expressed as a percentage (%) measured using dual-energy X-ray absorptiometry (DXA).

Height

Height, measured in centimeters (cm) using a wall-mounted stadiometer

Lipid profile

Lipid profile including total cholesterol (mg/dl), LDL cholesterol (mg/dl), HDL cholesterol (mg/dl), triglycerides (mg/dl), VLDL cholesterol (mg/dl), and non-HDL cholesterol (mg/dl) measured using standard enzymatic methods.

Liver enzymes

Liver enzymes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), and alkaline phosphatase (ALP), measured in units per liter (U/L) using standard laboratory methods.

Total and direct bilirubin

Total and direct bilirubin, measured in micromoles per liter (µmol/L) using standard laboratory methods.

Serum albumin and total protein

Serum albumin and total protein, measured in grams per liter (g/L) using standard laboratory methods.

Glycated hemoglobin

Glycated hemoglobin (HbA1c), measured as a percentage (%) using standardized laboratory assays.

Dietary intake

Dietary intake, assessed using a validated Food Frequency Questionnaire (FFQ) to estimate habitual energy and nutrient intake. Nutrient and energy intake are expressed in grams per day (g/day), milligrams per day (mg/day), micrograms per day (µg/day), or kilocalories per day (kcal/day), depending on the dietary component evaluated.

Mediterranean diet adherence

Mediterranean diet adherence, assessed using the 14-item Mediterranean Diet Adherence Screener (MEDAS). Scores range from 0 to 14, with higher scores indicating greater adherence to the Mediterranean diet.

Culinary habits

Culinary habits, assessed using the Home Cooking Frequency Questionnaire (HCFQ). The questionnaire evaluates the frequency of home cooking, food preparation behaviors, and culinary skills. Higher scores indicate greater frequency of home cooking and healthier culinary practices.

Reduced and oxidized glutathione

Reduced and oxidized glutathione (GSH and GSSG), measured in micromoles per liter (µmol/L) using enzymatic or chromatographic methods.

Gut microbiota composition

Gut microbiota composition, assessed by 16S ribosomal RNA (16S rRNA) gene sequencing of fecal DNA. Relative abundance of bacterial taxa is expressed as percentage (%).

Superoxide dismutase

Superoxide dismutase (SOD), measured in units per milliliter (U/mL) using standardized enzymatic assays.

F2-isoprostanes

F2-isoprostanes, measured in picograms per milliliter (pg/mL) using liquid chromatography-tandem mass spectrometry (LC-MS/MS) or enzyme-linked immunosorbent assay (ELISA).

Malondialdehyde

Malondialdehyde (MDA), measured in micromoles per liter (µmol/L) using high-performance liquid chromatography (HPLC) or validated colorimetric assays.

Catalase

Catalase (CAT), measured in units per liter (U/L) using standardized enzymatic assays.

Inflammatory biomarkers

Inflammatory biomarkers, including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and ghrelin, measured in picograms per milliliter (pg/mL) using multiplex immunoassays or enzyme-linked immunosorbent assay (ELISA).

Adipokines

Adipokines, including leptin and visfatin, measured in nanograms per milliliter (ng/mL) using multiplex immunoassays or enzyme-linked immunosorbent assay (ELISA).

Adiponectin

Adiponectin, measured in micrograms per milliliter (µg/mL) using enzyme-linked immunosorbent assay (ELISA).

High-sensitivity C-reactive protein

High-sensitivity C-reactive protein (hs-CRP), measured in milligrams per liter (mg/L) using immunoturbidimetric or immunoassay methods.

Circulating polyphenols and plasma carotenoids

Circulating polyphenols and plasma carotenoids, measured in micromoles per liter (µmol/L) using high-performance liquid chromatography (HPLC) coupled with mass spectrometry.

Urinary polyphenols

Urinary polyphenols, measured in milligrams of gallic acid equivalents per gram of creatinine (mg GAE/g creatinine) using the Folin-Ciocalteu method or chromatographic techniques.

Advanced glycation end products

Advanced glycation end products (AGEs), measured in nanograms per milliliter (ng/mL) using enzyme-linked immunosorbent assay (ELISA).

Fecal short-chain fatty acids

Fecal short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate, measured in micromoles per gram of feces (µmol/g) using gas chromatography with flame ionization detection (GC-FID).

Health-related quality of life

Health-related quality of life, assessed using the 36-Item Short Form Health Survey (SF-36). Scores range from 0 to 100 for each of the eight domains and the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores, with higher scores indicating better health-related quality of life.

Physical activity,

Physical activity, assessed using the International Physical Activity Questionnaire-Short Form (IPAQ-SF). Physical activity is expressed as metabolic equivalent of task (MET)-minutes per week (MET-min/week), with higher values indicating greater levels of physical activity.