Effects of Daily Walnut Intake Among the Subjects With Metabolic Syndrome

Study Overview
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Brief Summary
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Investigators planed to conduct a randomized, controlled, crossover trial to examine the effects of daily walnuts intake among Korean subjects with metabolic syndrome. Primary objective of this study was to investigate the effects of daily walnut intake on changes of metabolic syndrome indices in Koreans with metabolic syndrome age over 30 years old. This study was consisted of four periods: run-in, first intervention, wash-out, and second intervention phases. As 16 weeks of first intervention period began after the run-in phase, the subjects were randomly assigned into one of two groups: walnut group and control group. Participants in walnut group consumed 45 grams of walnuts on a daily basis and participants in control group were provided iso-caloric white bread for first 16 weeks. After the first intervention and wash-out period (6 weeks), second intervention which is crossover of first intervention was started during the next 16 weeks. Anthropometric measurements and biochemical analyses were done at the beginning and the end of each intervention (0, 16, 22, and 38 weeks of trial). Habitual diet was randomly observed using 3-day diet record once during each phase. Investigators expected to evaluate 1)effects of walnut ingestion on reverting metabolic syndrome to normal status especially by reducing waist circumference and improving serum levels of triglyceride and high-density lipoprotein, 2)beneficial effects of daily walnut consumption on changes of body composition in the subjects with metabolic syndrome, and 3)regulatory effects of daily walnut intake on inflammatory markers and diabetic markers.

Official Title
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Effects of Daily Walnut Intake Among the Subjects With Metabolic Syndrome in South Korea

Conditions
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Metabolic Syndrome

Intervention / Treatment
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* Other: food


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: at least three out of five metabolic syndrome components waist circumference (WC) >90 cm for men and >80 cm for women hypertension (DBP ≥85 and <110 mm Hg) hyperglycemia (≥100 mg/dL) elevated plasma TG concentrations (≥150 mg/dL) decreased plasma HDL-C concentrations (<40 mg/dL for men and <50 mg/dL for women) Exclusion Criteria: the presence of morbid obesity (BMI ≥40) the use of any medication for the control of blood pressure, glucose, or lipid metabolism a medical history of hypocaloric diet consumption within the past year gastrointestinal tract disorders post-menopausal women smokers

Ages Eligible for Study
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Minimum Age: 30 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Walnut-Control<br> | Other: food<br>* 45 g of walnut / iso-caloric white bread<br>|
| Experimental: Control-Walnut<br> | Other: food<br>* 45 g of walnut / iso-caloric white bread<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| changes of waist circumference | Waist circumferences (cm) were obtained at the midpoint between the lowest rib and the iliac crest and rounded to the nearest 0.1 cm after inhalation and exhalation. | after 16 weeks of daily walnut consumption | 
| changes of blood triglyceride level | Serum triglycerides (mg/dL) levels were measured by an enzymatic-colorimetric method. | after 16 weeks of daily walnut consumption | 
| changes of blood high-density lipoprotein cholesterol levels | High density lipoprotein cholesterol (mg/dL) levels were determined by a homogeneous enzymatic-colorimetric method. | after 16 weeks of daily walnut consumption | 
| changes of blood pressure | Blood pressure (mmHg) was measured on the right arm using an up-load blood pressure monitor with participants in a comfortably seated position after at least a 5-minute rest. | after 16 weeks of daily walnut consumption | 
| changes of blood glucose level | Blood glucose levels (mg/dL) were measured using blood glucose monitor and test stripts from the finger tip. | after 16 weeks of daily walnut consumption | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| changes of total cholesterol level | Serum total cholesterol levels (ml/dL) were measured by an enzymatic-colorimetric method. | after 16 weeks of daily walnut consumption | 
| changes of serum apolipoprotein B level | Serum apolipoprotein B (ml/dL) was measured using a turbidimetric immunoassay. | after 16 weeks of daily walnut consumption | 
| changes of serum adiponectin level | Blood adiponectin (ug/mL) levels were measured using ELISA. | after 16 weeks of daily walnut consumption | 
| changes of serum leptin level | Blood leptin (ug/mL) levels were measured using ELISA. | after 16 weeks of daily walnut consumption | 
| changes of serum insulin level | Serum insulin (μU/mL) was measured with a commercially available kit, the ultrasensitive insulin ELISA kit using an Epoch microplate spectrophotometer. | after 16 weeks of daily walnut consumption | 
| changes of low-density lipoprotein cholesterol level | Low-density lipoprotein cholesterol levels (ml/dL) were determined by a homogeneous enzymatic-colorimetric method. | after 16 weeks of daily walnut consumption |