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Soy Protein Intake and the Metabolic Syndrome (SOY)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01694056
Recruitment Status : Completed
First Posted : September 26, 2012
Last Update Posted : January 4, 2013
Alpro Foundation
Information provided by (Responsible Party):
Wageningen University

Brief Summary:
Soy protein has a high biological value, and contains several potential health-related nutritional factors, i.e. its amino acids pattern, biological active peptides and non-protein compounds such as isoflavones. In the field of obesity and blood lipids soy protein is well-studied and appreciated; it improves circulating blood lipids and is associated with weight reduction. The effect of soy on insulin resistance, glucose homeostasis and the metabolic syndrome is less frequently studied. However, several molecular mechanisms of action of soy protein make it a promising approach.

Condition or disease Intervention/treatment Phase
Metabolic Syndrome X Other: Soy protein diet Other: Control diet Not Applicable

Detailed Description:

Objective: The primary objective of the present study is to evaluate the effect of a high soy protein diet on insulin resistance and glycemic control in participants with characteristics of the metabolic syndrome. Secondly, the present study will evaluate whether reduced low-grade inflammation is a possible mechanism underlying the improvement in insulin resistance and glucose homeostasis. Finally, it will be assessed whether soy protein has beneficial effects on components of the metabolic syndrome, such as cardio-metabolic risk factors, blood lipid profile, blood pressure and endothelial function, fat storage in the liver and gene-expression in subcutaneous abdominal adipose tissue.

Study design: Single-blind, cross-over strictly-controlled dietary intervention.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 15 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Investigator)
Primary Purpose: Prevention
Official Title: Soy Protein Intake and the Metabolic Syndrome: Reducing Inflammation to Improve Insulin Resistance and Glucose Homeostasis
Study Start Date : September 2012
Actual Primary Completion Date : December 2012
Actual Study Completion Date : December 2012

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Soy protein diet
High mixed protein diet (20 en%) with 25gr of soy protein per day
Other: Soy protein diet
4 weeks high protein diet (20 en%) with 25gr of soy protein per day

Active Comparator: Control diet
High mixed protein diet (20 en%)
Other: Control diet
4 weeks high mixed protein diet (20 en%)

Primary Outcome Measures :
  1. Insulin sensitivity [ Time Frame: 4 weeks ]
    Insulin sensitivity is measured with an intravenous glucose tolerance test (IVGTT).

Secondary Outcome Measures :
  1. Adipose tissue gene expression [ Time Frame: 4 weeks ]
    Adipose tissue samples will be collected for subsequent gene expression analysis.

  2. Blood lipids [ Time Frame: 4 weeks ]
    Circulating triglycerides, free fatty acids (FFA), and HDL and total cholesterol will be measured in fasted blood samples, LDL will be calculated.

  3. Inflammation markers and adipokines [ Time Frame: 4 weeks ]
    For low-grade inflammation interleukins, tumor necrosis factor-α, C-reactive protein and adipokines will be measured in fasting blood samples. Furthermore, peripheral blood mononuclear cells (PBMC's) will be collected to measure expression of genes involved in lipid handling and inflammation.

  4. Cardio-metabolic risk factors [ Time Frame: 4 weeks ]
    Blood pressure and macro vascular regional arterial stiffness will be assessed by Pulse Wave Analysis (PWA). Besides PWA, we will also measure markers for endothelial function in fasting blood samples.

  5. Hepatic lipid content [ Time Frame: 4 weeks ]
    Hepatic lipid content The lipid content in liver will be quantified by proton magnetic resonance spectroscopy (1H -MRS)

Information from the National Library of Medicine

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Ages Eligible for Study:   45 Years to 70 Years   (Adult, Older Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Women
  • 45-70 years
  • No menstrual cycle for ≥1 year
  • Stable body weight for ≥6 months (no weight gain/loss > 3 kg)
  • Stable exercise habits during the last 6 months, and not participating in any vigorous exercise program
  • Central obesity: waist circumference ≥80 cm

Plus any one of the following four factors:

  • Raised triglyceride level: ≥1.7 mmol/L;
  • Reduced high-density lipoprotein (HDL) cholesterol: <1.29 mmol/L
  • Raised blood pressure: systolic blood pressure ≥135 mmHg or diastolic BP ≥85 mmHg or use of blood pressure lowering medication
  • Raised fasting plasma glucose ≥ 5.6 mmol/L

Exclusion Criteria:

  • (Undiagnosed) Diabetes - but not impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT) as evaluated by an oral glucose tolerance test at screening
  • Active hearth disease, i.e. history of myocardial infarction, stroke or angina pectoris
  • Active or a history of thyroid disease
  • Cancer or other malignancies in the past 5 years
  • Two sided ovariectomy
  • Drug use knowing to interfere with objectives of the study
  • oral corticosteroids, lipid-lowering drugs (statins)
  • anti-conceptive use (such as the pill or IUD)
  • hormone replacement therapy
  • long-term antibiotics use
  • Habitual intake of soy foods (>1 soy food per week)
  • Isoflavone supplements
  • Vegetarian
  • Following, or have recently followed a (weight-loss) diet
  • Allergic to soy or dairy products
  • Smoking
  • Consuming more than 14 glasses of alcohol per week
  • Donated or intended to donate blood 2 months before till two months after the study
  • Participation in another biomedical study within 1 month before the first screening visit
  • Not willing to be informed if deviations are found in blood samples
  • Contraindications to MRI scanning

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01694056

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Wageningen University
Wageningen, Netherlands, 6703 HD
Sponsors and Collaborators
Wageningen University
Alpro Foundation
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Study Chair: Marco Mensink, PhD Departement of Human Nutrition, Wageningen University

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Wageningen University Identifier: NCT01694056    
Other Study ID Numbers: NL39991.081.12
First Posted: September 26, 2012    Key Record Dates
Last Update Posted: January 4, 2013
Last Verified: January 2013
Additional relevant MeSH terms:
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Metabolic Syndrome
Pathologic Processes
Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases