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Completed

NCT Number: NCT03267901

Effects of Daily Walnut Intake Among the Subjects With Metabolic Syndrome

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.

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Key information

Age range

30 year–55 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

ICAN Nutrition Education and Research

Seoul, 07327, South Korea

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Food

Other

45 g of walnut / iso-caloric white bread

Primary outcomes

  1. changes of waist circumference

    Time frame: after 16 weeks of daily walnut consumption

    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.

  2. changes of blood triglyceride level

    Time frame: after 16 weeks of daily walnut consumption

    Serum triglycerides (mg/dL) levels were measured by an enzymatic-colorimetric method.

  3. changes of blood high-density lipoprotein cholesterol levels

    Time frame: after 16 weeks of daily walnut consumption

    High density lipoprotein cholesterol (mg/dL) levels were determined by a homogeneous enzymatic-colorimetric method.

  4. changes of blood pressure

    Time frame: after 16 weeks of daily walnut consumption

    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.

  5. changes of blood glucose level

    Time frame: after 16 weeks of daily walnut consumption

    Blood glucose levels (mg/dL) were measured using blood glucose monitor and test stripts from the finger tip.

Secondary outcomes

  1. changes of total cholesterol level

    Time frame: after 16 weeks of daily walnut consumption

    Serum total cholesterol levels (ml/dL) were measured by an enzymatic-colorimetric method.

  2. changes of serum apolipoprotein B level

    Time frame: after 16 weeks of daily walnut consumption

    Serum apolipoprotein B (ml/dL) was measured using a turbidimetric immunoassay.

  3. changes of serum adiponectin level

    Time frame: after 16 weeks of daily walnut consumption

    Blood adiponectin (ug/mL) levels were measured using ELISA.

  4. changes of serum leptin level

    Time frame: after 16 weeks of daily walnut consumption

    Blood leptin (ug/mL) levels were measured using ELISA.

  5. changes of serum insulin level

    Time frame: after 16 weeks of daily walnut consumption

    Serum insulin (μU/mL) was measured with a commercially available kit, the ultrasensitive insulin ELISA kit using an Epoch microplate spectrophotometer.

  6. changes of low-density lipoprotein cholesterol level

    Time frame: after 16 weeks of daily walnut consumption

    Low-density lipoprotein cholesterol levels (ml/dL) were determined by a homogeneous enzymatic-colorimetric method.

Sponsors and collaborators

Lead sponsor

ICAN Nutrition Education and Research

Industry

Collaborators

  • California Walnut Commission

Registry information

Official study title

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

Important dates

Study start
2015
Primary completion
2017
Study completion
2017
First posted
Aug 30, 2017
Registry last updated
Aug 30, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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