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Soy Nut Study on Markers of Health

Sponsor
University of California, Davis (Other)
Overall Status
Completed
CT.gov ID
NCT01173380
Collaborator
(none)
18
Enrollment
1
Location
2
Arms
25
Duration (Months)
0.7
Patients Per Site Per Month

Study Details

Study Description

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
  • Other: Soy nuts
  • Other: Matched food
 N/A

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 Design

Study Type:
Interventional
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 :
Aug 1, 2010
Actual Primary Completion Date :
Sep 1, 2012
Actual Study Completion Date :
Sep 1, 2012

Arms and Interventions

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 Names:
  • Genisoy

    		•

    Outcome Measures

    Primary Outcome Measures

    1. Improve lipid profile [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 [After 4 week intervention]

      Brachial artery flow mediated dilation, reactive hyperemia peripheral arterial tonometry, blood pressure, endothelin-1

    3. Attenuate glycemic responses [After 4 week intervention]

      Fasting plasma glucose, insulin, fructosamine, homeostasis model assessment of insulin resistance

    Secondary Outcome Measures

    1. Decrease inflammatory markers [After 4 week intervention]

      High sensitivity C reactive protein, vascular cell adhesion molecule-1, intercellular adhesion molecule-1

    2. Follow anthropometrics for stable weight [After 4 week intervention]

      Weight, height, body mass index, waist circumference, hip circumference, waist:hip ratio

    Eligibility Criteria

    Criteria

    Ages Eligible for Study:
    21 Years and Older
    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

    Contacts and Locations

    Locations

    Site City State Country Postal Code
    1 Ragle Human Nutrition Center Davis California United States 95616

    Sponsors and Collaborators

    • University of California, Davis

    Investigators

    • Principal Investigator: Francene M Steinberg, PhD, RD, UC Davis

    Study Documents (Full-Text)

    None provided.

    More Information

    Publications

    Responsible Party:
    University of California, Davis
    ClinicalTrials.gov Identifier:
    NCT01173380
    Other Study ID Numbers:
    • 200715715-4
    First Posted:
    Aug 2, 2010
    Last Update Posted:
    May 30, 2017
    Last Verified:
    May 1, 2017
    Keywords provided by University of California, Davis
    Soy
    Equol
    Metabolic syndrome
    Endothelial function
    Additional relevant MeSH terms:
    Metabolic Syndrome

    Study Results

    No Results Posted as of May 30, 2017