Soy Nut Study on Markers of Health

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: NCT01173380
Recruitment Status : Completed
First Posted : August 2, 2010
Last Update Posted : May 30, 2017
Information provided by (Responsible Party):
University of California, Davis

Brief Summary:
The investigators hope to learn about the effects of soy nuts on markers of health. When some people eat soy foods, their gut bacteria make equol. Equol is a soy metabolite (small molecule made during metabolism). The investigators will be testing blood samples to determine if markers of health are different for people who make equol versus people who do not make equol.

Condition or disease Intervention/treatment Phase
Metabolic Syndrome X Other: Soy nuts Other: Matched food Not Applicable

Detailed Description:

The objective of the study is to investigate the metabolomic response to consumption of soy protein containing polyphenolic phytochemicals (isoflavones). The aim of this pilot study is to demonstrate proof of concept and ability to detect metabolomic changes that are responsive to soy. This preliminary data will then be used to design future research projects.

Food phytochemicals such as the polyphenolic flavonoids from a wide variety of foods and beverages have been associated with cardiovascular protective effects in epidemiologic studies. Significant controversy exists in the literature regarding the efficacy and mechanisms for the cardiovascular protection of soy foods. The soy hypothesis for cardiovascular risk reduction has been focused mainly on the isoflavone content of soy, but uncertainty still exists regarding the bioactive component(s). In particular, consumption of soy protein foods has been associated with favorable cardiovascular disease (CVD) risk profiles in population based studies. Controlled clinical trials and meta-analyses however, have resulted in the conclusions that soy protein with associated isoflavones has only modest hypocholesterolemic effects in the range of 3-5% reduction in LDL-cholesterol. Additional cardioprotective effects have been demonstrated in clinical trials, promoting small but significant changes in vascular endothelial function and antioxidant protection. An important observation is that animal studies have shown reduction in atherosclerotic lesion size both with and without decreased blood lipid levels. These results taken together suggest that soy and soy phytochemicals can promote positive risk factors and outcomes by mechanisms in addition to, and other than lowering serum cholesterol levels. There is a need for greater understanding of the cellular and molecular mechanisms underlying the physiologic responses to isoflavones in the vascular compartment. Increasing evidence is emerging that biologically relevant concentrations of isoflavones may impact cell signaling processes in vascular and other tissues.

The large body of literature on human clinical trials of soy proteins and isoflavones has focused primarily on traditional lipid and lipoprotein parameters, biomarkers of CVD risk, and functional changes in endothelial function, platelet activation and total blood antioxidant capacity as described above. It is possible and likely that the effect of soy consumption on CVD risk is a net result of multiple subtle changes in metabolic pathways, vascular inflammatory responses and cell-signaling pathways which are not readily detected in healthy individuals. Since individuals with metabolic syndrome (MetS) present with many of the metabolic aberrations purported to be improved through soy food ingestion, these individuals may be an excellent study population in order to investigate the effects of a soy food intervention on metabolic markers of health. Equol is the end-product of daidzein biotransformation, and is produced only by some humans, resulting in a phenotypic characteristic in response to dietary soy. It is hypothesized by some researchers that the "equol producers" may have additional metabolic and phenotypic responses to soy which may help to explain some of the variances in the literature. Few investigators have examined this question in existing studies, with two reporting an association with outcomes and one no association. A recent study using microarray analysis of lymphocytes from postmenopausal women demonstrated differential gene expression in women who form equol compared to those who do not, suggesting that equol status may be an important modulator of responses to soy isoflavones. No studies have examined this question in a metabolomic investigation. This demonstrates a gap in the literature and provides an opportunity to contribute significant novel data using cutting-edge approaches.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 18 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Effects of Soy on Metabolite Markers of Health
Study Start Date : August 2010
Actual Primary Completion Date : September 2012
Actual Study Completion Date : September 2012

Resource links provided by the National Library of Medicine

U.S. FDA Resources

Arm Intervention/treatment
Sham Comparator: Matched food
Control food (matched for calories and macronutrients) per day for 4 weeks
Other: Matched food
Control food (matched for calories and macronutrients) per day for 4 weeks
Active Comparator: Soy nuts
Oil roasted soy nuts with 101 milligrams of soy isoflavones per day for 4 weeks
Other: Soy nuts
Oil roasted soy nuts with 101 milligrams of soy isoflavones per day for 4 weeks
Other Name: Genisoy

Primary Outcome Measures :
  1. Improve lipid profile [ Time Frame: After 4 week intervention ]
    Total cholesterol, low density lipoprotein cholesterol, high density lipoprotein cholesterol, triglyceride level, apolipoproteinA1, apolipoproteinB100, apolipoproteinB100:apolipoproteinA1, urinary F2-isoprostane

  2. Increase endothelial function [ Time Frame: After 4 week intervention ]
    Brachial artery flow mediated dilation, reactive hyperemia peripheral arterial tonometry, blood pressure, endothelin-1

  3. Attenuate glycemic responses [ Time Frame: After 4 week intervention ]
    Fasting plasma glucose, insulin, fructosamine, homeostasis model assessment of insulin resistance

Secondary Outcome Measures :
  1. Decrease inflammatory markers [ Time Frame: After 4 week intervention ]
    High sensitivity C reactive protein, vascular cell adhesion molecule-1, intercellular adhesion molecule-1

  2. Follow anthropometrics for stable weight [ Time Frame: After 4 week intervention ]
    Weight, height, body mass index, waist circumference, hip circumference, waist:hip ratio

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Ages Eligible for Study:   21 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Postmenopausal women
  • Men ages 45 or above
  • Blood pressure greater than or equal to 130/85 mmHg but not greater than 160/100 and meeting an additional 2 of the remaining 4 Metabolic syndrome diagnostic criteria as defined by NCEP ATP III:

    1. Elevated waist circumference: men equal to or greater than 40 inches, women equal to or greater than 35 inches
    2. Reduced HDL cholesterol: men less than 40 mg/dL, women less than 50 mg/dL
    3. Fasting glucose greater than or equal to 100 mg/dL
    4. Fasting blood triglycerides greater than or equal to 150 mg/dL but less than 400 mg/dL
  • Weight of at least 110 pounds

Exclusion Criteria:

  • Smokers
  • Chronic disease, such as diabetes, cancer, renal disease, and blood disorders
  • History of intestinal disorders, which affect absorption or transit, such as ulcerative colitis or crohns disease
  • Allergy to soy
  • Antioxidant supplement usage

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): NCT01173380

United States, California
Ragle Human Nutrition Center
Davis, California, United States, 95616
Sponsors and Collaborators
University of California, Davis
Principal Investigator: Francene M Steinberg, PhD, RD UC Davis


Responsible Party: University of California, Davis Identifier: NCT01173380     History of Changes
Other Study ID Numbers: 200715715-4
First Posted: August 2, 2010    Key Record Dates
Last Update Posted: May 30, 2017
Last Verified: May 2017

Keywords provided by University of California, Davis:
Metabolic syndrome
Endothelial function

Additional relevant MeSH terms:
Metabolic Syndrome X
Insulin Resistance
Glucose Metabolism Disorders
Metabolic Diseases