Soy Protein Intake and the Metabolic Syndrome (SOY)
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 Design:||Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Single Blind (Investigator)
Primary Purpose: Prevention
|Official Title:||Soy Protein Intake and the Metabolic Syndrome: Reducing Inflammation to Improve Insulin Resistance and Glucose Homeostasis|
- Insulin sensitivity [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]Insulin sensitivity is measured with an intravenous glucose tolerance test (IVGTT).
- Adipose tissue gene expression [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]Adipose tissue samples will be collected for subsequent gene expression analysis.
- Blood lipids [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]Circulating triglycerides, free fatty acids (FFA), and HDL and total cholesterol will be measured in fasted blood samples, LDL will be calculated.
- Inflammation markers and adipokines [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]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.
- Cardio-metabolic risk factors [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]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.
- Hepatic lipid content [ Time Frame: 4 weeks ] [ Designated as safety issue: No ]Hepatic lipid content The lipid content in liver will be quantified by proton magnetic resonance spectroscopy (1H -MRS)
|Study Start Date:||September 2012|
|Study Completion Date:||December 2012|
|Primary Completion Date:||December 2012 (Final data collection date for primary outcome measure)|
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%)
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.
|Wageningen, Netherlands, 6703 HD|
|Study Chair:||Marco Mensink, PhD||Departement of Human Nutrition, Wageningen University|