Soy Protein Intake and the Metabolic Syndrome (SOY)

Soy Protein Intake and the Metabolic Syndrome: Reducing Inflammation to Improve Insulin Resistance and Glucose Homeostasis

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.

Study Overview

• Status: Completed
• Conditions: Metabolic Syndrome X
• Intervention / Treatment: Other: Soy protein diet; Other: Control diet

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.

• Study Type: Interventional
• Enrollment (Actual): 15
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Netherlands
  • Wageningen, Netherlands, 6703 HD
    • Wageningen University

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 45 years to 70 years (ADULT, OLDER_ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: PREVENTION
• Allocation: RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: SINGLE

Number of Arms

2

Arms and Interventions

Participant Group / 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%)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Insulin sensitivity	Insulin sensitivity is measured with an intravenous glucose tolerance test (IVGTT).	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Adipose tissue gene expression	Adipose tissue samples will be collected for subsequent gene expression analysis.	4 weeks
Blood lipids	Circulating triglycerides, free fatty acids (FFA), and HDL and total cholesterol will be measured in fasted blood samples, LDL will be calculated.	4 weeks
Inflammation markers and adipokines	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 weeks
Cardio-metabolic risk factors	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.	4 weeks
Hepatic lipid content	Hepatic lipid content The lipid content in liver will be quantified by proton magnetic resonance spectroscopy (1H -MRS)	4 weeks

Collaborators and Investigators

• Sponsor: Wageningen University
• Collaborators: Alpro Foundation
• Investigators: Study Chair: Marco Mensink, PhD, Departement of Human Nutrition, Wageningen University

Publications and helpful links

General Publications

• van Nielen M, Feskens EJ, Rietman A, Siebelink E, Mensink M. Partly replacing meat protein with soy protein alters insulin resistance and blood lipids in postmenopausal women with abdominal obesity. J Nutr. 2014 Sep;144(9):1423-9. doi: 10.3945/jn.114.193706. Epub 2014 Jul 9.

Study record dates

Study Major Dates

• Study Start: September 1, 2012
• Primary Completion (ACTUAL): December 1, 2012
• Study Completion (ACTUAL): December 1, 2012

Study Registration Dates

• First Submitted: September 4, 2012
• First Submitted That Met QC Criteria: September 24, 2012
• First Posted (ESTIMATE): September 26, 2012

Study Record Updates

• Last Update Posted (ESTIMATE): January 4, 2013
• Last Update Submitted That Met QC Criteria: January 3, 2013
• Last Verified: January 1, 2013

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: NL39991.081.12