The purpose of this study is to determine if supplementing a Chilean diet with Chilean hazelnut (Gevuina avellana) improves cholesterol levels in adults with hypercholesterolemia. The main question is whether this supplementation reduces total serum cholesterol compared to a low-fat diet without hazelnut.
This is a 6-month randomized controlled parallel study involving hypercholesterolemic volunteers (serum cholesterol \> 200 mg/dL, with or without triglycerides \> 150 mg/dL) aged 18-60 years from Concepción, Chile. Participants are randomly assigned to two groups: Intervention group: Receives the Chilean diet supplemented daily with 30 g of Chilean hazelnut (Gevuina avellana). Control group: Receives dietary advice to follow a low-fat diet based on American Heart Association recommendations, without hazelnut supplementation. Primary outcome is total serum cholesterol. Secondary assessments include anthropometric measures, blood pressure, diet adherence, physical activity, sociodemographic variables, smoking habits, medical diagnoses, medication use, and biochemical markers of lipid profile, oxidative damage, antioxidant capacity, endothelial peptides, and inflammation. Data collection occurs at baseline, 2, 4, and 6 months. Individual motivational interviews and group motivational sessions (approximately 25 participants each) are conducted to enhance adherence. Blood samples for lipid profiling and other biochemical analyses are collected fasting at baseline and study completion. Blood fractionation is performed to obtain plasma, serum, erythrocytes, and peripheral blood mononuclear cells (PBMCs) for detailed fatty acid profiling and biomarker measurements. This study aims to provide insight into the potential cardiovascular benefits of Gevuina avellana supplementation in a Chilean dietary context.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
106
The group follows a Chilean diet (adapted from the Mediterranean Diet using Chilean ingredients) supplemented with 30 g/day of Gevuina avellana and providing 40% of total energy value from fat. To promote adherence to the diet, individual motivational interviews and group sessions (with approximately 25 participants) are conducted once per month. Each participant is provided once a month with individually packaged Chilean hazelnuts to reach a daily intake of 30 g.
The group maintains a low-fat diet (\<30% of total energy value) based on the Chilean Ministry of Health (MINSAL) technical guidelines for dyslipidemia management. To promote adherence to the diet, individual motivational interviews and group sessions (with approximately 25 participants) are conducted once per month.
Laboratorio Prevegen
Concepción, Biobio, Chile
Total cholesterol (mg/dL)
Total serum cholesterol under fasting condition
Time frame: From enrollment to the end of treatment at 6 months
Blood pressure (mmHg)
Blood pressure measured by a semi-automatic sphygmomanometer
Time frame: From enrollment to the end of treatment at 6 months
Body weight (kg)
Body weight is measured using a portable digital scale (Seca®) with a precision of 100 g, placed on a flat, horizontal, and firm surface. Participants are asked to remove their shoes and wear minimal clothing to ensure accurate measurement.
Time frame: From enrollment to the end of treatment at 6 months
Height (m)
Height is measured using a portable stadiometer (Seca® 213) with 0.1 cm precision. Participants stand barefoot with heels together (forming a 45-60° angle), back straight and in contact with the stadiometer, fully extended. The head is positioned in the Frankfurt horizontal plane. Participants are instructed to take a deep breath and remain still. The headpiece is gently lowered to contact the head, applying slight pressure to compress the hair.
Time frame: From enrollment to the end of treatment at 6 months
Body Mass Index (kg/m2)
Weight and height will be combined to report BMI in kg/m2)
Time frame: From enrollment to the end of treatment at 6 months
Waist circumference (mm)
Waist circumference is measured using a non-stretchable measuring tape (Seca® 201) with 0.1 cm precision. The participant stands upright, shirtless or with the waist area exposed, feet 25-30 cm apart, arms relaxed at the sides, and weight evenly distributed. Measurement is taken at the midpoint between the lower rib and the iliac crest along the midaxillary line. Reference points are palpated and marked. The tape is placed horizontally, snug but not compressing soft tissues, and measurement is taken at the end of a normal exhalation. Two measurements are taken; if they differ by more than 1 cm, a third is taken. The final value is the average of the two closest readings.
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Time frame: From enrollment to the end of treatment at 6 months
LDL cholesterol (mg/dL)
LDL cholesterol under fasting condition
Time frame: From enrollment to the end of treatment at 6 months
HDL cholesterol (mg/dL)
HDL cholesterol under fasting condition
Time frame: From enrollment to the end of treatment at 6 months
Triglycerides (mg/dL)
Triglycerides under fasting condition
Time frame: From enrollment to the end of treatment at 6 months
Superoxide dismutase activity
Superoxide dismutase activity is measured in plasma and erythrocytes using spectrophotometric methods.
Time frame: From enrollment to the end of treatment at 6 months
Catalase activity
Catalase is measured in plasma and erythrocytes using spectrophotometric methods.
Time frame: From enrollment to the end of treatment at 6 months
Homocysteine
Plasma homocysteine is measured using a commercial ELISA kit, following the manufacturer's instructions.
Time frame: From enrollment to the end of treatment at 6 months
Adiponectin
Adiponectin levels in plasma are measured using a commercial ELISA kit according to the manufacturer's protocol
Time frame: From enrollment to the end of treatment at 6 months
Oxidized low-density lipoprotein (LDLox)
Oxidized low-density lipoprotein (LDLox) levels in plasma are measured using a commercial ELISA kit following the manufacturer's instructions.
Time frame: From enrollment to the end of treatment at 6 months