Soy Protein Intake and the Metabolic Syndrome (SOY)

Wageningen University

Status

Completed

Conditions

Metabolic Syndrome X

Treatments

Other: Soy protein diet

Other: Control diet

Study type

Interventional

Funder types

Other

Identifiers

NCT01694056

NL39991.081.12

Details and patient eligibility

About

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.

Full 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.

Enrollment

15 patients

Sex

Female

Ages

45 to 70 years old

Volunteers

Accepts Healthy Volunteers

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