Effects of Daily Walnut Intake Among the Subjects With Metabolic Syndrome

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

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.

Study Overview

• Status: Completed
• Conditions: Metabolic Syndrome
• Intervention / Treatment: Other: food

• Study Type: Interventional
• Enrollment (Actual): 119
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Korea, Republic of
  • Seoul, Korea, Republic of, 07327
    • ICAN Nutrition Education and Research

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 55 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Walnut-Control	Other: food; 45 g of walnut / iso-caloric white bread
Experimental: Control-Walnut	Other: food; 45 g of walnut / iso-caloric white bread

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: ICAN Nutrition Education and Research
• Collaborators: California Walnut Commission

Publications and helpful links

General Publications

• Hwang HJ, Liu Y, Kim HS, Lee H, Lim Y, Park H. Daily walnut intake improves metabolic syndrome status and increases circulating adiponectin levels: randomized controlled crossover trial. Nutr Res Pract. 2019 Apr;13(2):105-114. doi: 10.4162/nrp.2019.13.2.105. Epub 2019 Feb 11.

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2015
• Primary Completion (Actual): July 30, 2017
• Study Completion (Actual): July 30, 2017

Study Registration Dates

• First Submitted: August 14, 2017
• First Submitted That Met QC Criteria: August 28, 2017
• First Posted (Actual): August 30, 2017

Study Record Updates

• Last Update Posted (Actual): August 30, 2017
• Last Update Submitted That Met QC Criteria: August 28, 2017
• Last Verified: August 1, 2017

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Pathologic Processes; Glucose Metabolism Disorders; Metabolic Diseases; Disease; Insulin Resistance; Hyperinsulinism; Syndrome; Metabolic Syndrome
• Other Study ID Numbers: CWC-2016-MetS

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No