Effects of a Chilean Diet Supplemented With Gevuina Avellana on Lipid Profile in Humans With Hypercholesterolemia

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.

• High-fat diet (Dietary supplement), also known as Chilean hazelnut supplementation, Gevuina avellana supplementation: 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.
• Low-fat diet (Dietary supplement), also known as MINSAL guidelines for dyslipidemia management, Chilean Ministry of Health technical guidelines for dyslipidemia management: 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.

Primary outcomes

• Total cholesterol (mg/dL) [From enrollment to the end of treatment at 6 months]: Total serum cholesterol under fasting condition

Secondary outcomes

• Blood pressure (mmHg) [From enrollment to the end of treatment at 6 months]: Blood pressure measured by a semi-automatic sphygmomanometer
• Body weight (kg) [From enrollment to the end of treatment at 6 months]: 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.
• Height (m) [From enrollment to the end of treatment at 6 months]: 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.
• Body Mass Index (kg/m2) [From enrollment to the end of treatment at 6 months]: Weight and height will be combined to report BMI in kg/m2)
• Waist circumference (mm) [From enrollment to the end of treatment at 6 months]: 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.
• LDL cholesterol (mg/dL) [From enrollment to the end of treatment at 6 months]: LDL cholesterol under fasting condition
• HDL cholesterol (mg/dL) [From enrollment to the end of treatment at 6 months]: HDL cholesterol under fasting condition
• Triglycerides (mg/dL) [From enrollment to the end of treatment at 6 months]: Triglycerides under fasting condition
• Superoxide dismutase activity [From enrollment to the end of treatment at 6 months]: Superoxide dismutase activity is measured in plasma and erythrocytes using spectrophotometric methods.
• Catalase activity [From enrollment to the end of treatment at 6 months]: Catalase is measured in plasma and erythrocytes using spectrophotometric methods.
• Homocysteine [From enrollment to the end of treatment at 6 months]: Plasma homocysteine is measured using a commercial ELISA kit, following the manufacturer's instructions.
• Adiponectin [From enrollment to the end of treatment at 6 months]: Adiponectin levels in plasma are measured using a commercial ELISA kit according to the manufacturer's protocol
• Oxidized low-density lipoprotein (LDLox) [From enrollment to the end of treatment at 6 months]: Oxidized low-density lipoprotein (LDLox) levels in plasma are measured using a commercial ELISA kit following the manufacturer's instructions.

Sex: All, ages: 18 Years to 60 Years

Inclusion Criteria:

* Serum cholesterol level greater than 200 mg/dL with or without triacylglycerol greater than 150 mg/dL
* Have received both doses included in the SARS-CoV-2 vaccination campaign and possess their corresponding mobility pass.

Exclusion Criteria:

* Be undergoing medical treatment for hypercholesterolemia.
* Have systemic diseases such as diabetes, hypertension, kidney, or liver disease.
* Pregnant or breastfeeding women.
* Have a household member or close relative who has been previously recruited.
* Have allergies to tree nuts.
* Have an electronic implant such as a pacemaker.
* Also, individuals who do not meet the minimum conditions compatible with the study modality will not be able to participate in the intervention, such as: having access to an electronic device such as a cellphone or computer; having access to mobile internet or Wi-Fi at home; or having the necessary knowledge or support to use the platform

• Results publication: Ramos-Pardo S, Ramirez-Alarcon K, Gonzalez-Contreras C, Valdebenito E, Sureda A, Martorell M. Effect of a Chilean diet supplemented with Gevuina avellana molina versus a low-fat diet on cardiometabolic, oxidative stress, and inflammatory biomarkers in Chilean adults with hypercholesterolemia: A randomized controlled trial. Nutr Metab Cardiovasc Dis. 2026 Jun;36(6):104608. doi: 10.1016/j.numecd.2026.104608. Epub 2026 Feb 4. PMID 41791910

• Miquel Martorell, PhD, Principal investigator, Centro de Vida Saludable