Effect of 6-week Strawberry Supplementation on Insulin Action (STR2)

NCT ID: NCT01457612

Last Updated: 2023-02-08

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

NA

Total Enrollment

45 participants

Study Classification

INTERVENTIONAL

Study Start Date

2011-10-01

Study Completion Date

2013-03-01

Brief Summary

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The primary study objective is to investigate the potential chronic beneficial effect of polyphenolics derived from strawberry on impaired insulin signaling in insulin resistant individuals through their ability to modulate oxidative- and inflammatory-markers that lead to devastating disease, including, but not limited to, diabetes and cardiovascular disease.

Detailed Description

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This study is a single-center, randomized and single blinded, placebo-controlled, 6-week, parallel design study with follow-up to evaluate strawberry-associated chronic improvements in insulin action resulting in reduced whole body insulin resistance and improved glucose tolerance. This study will take approximately 11\~12 weeks.

Subjects will follow an extremely limited polyphenolic diet throughout the duration of their participation in the study.

The limited diet will begin 7 days before the first study visit and end before the last study visit. Following the polyphenol-free 7-day run in period, at Week 0, subjects will be scheduled to return to the Center for sequence randomization, an Oral Glucose Tolerance Test (OGTT) as well as a Flow Mediated Dilation (FMD) procedure to measure endothelial function. Subjects will incorporate either one of tow Placebo Beverages (PBO1, n=15; PBO2, n=15) or Strawberry Beverage (STR, n=15, an optimal strawberry test dose of 40 g/d) into their diet daily for a period of 6 weeks. Subjects will consume randomly assigned beverage twice per day with their breakfast and dinner meals.

All subjects will be asked to come to the Center once a week where they will receive a week's supply of beverages. Additionally, fasting clinical and laboratory variables, anthropometrics, and vital sign measurements will be assessed at each bi-weekly visit at Week 3 and Week 5.

Participants will undergo the same procedures at the end of Week 6: fasting blood sample collection for analysis of insulin, glucose, oxidative and inflammatory markers, an OGTT to assess glucose handling, as well as a FMD procedure to assess endothelial function in response to 6 weeks of either the Placebo or Strawberry treatment.

Subjects will be required to visit the Center 4 weeks after the end of their intervention period (Week 10), at which time they will undergo their last anthropometrics and vital sign measurements, a 4 hour OGTT, and the FMD procedure.

Conditions

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Insulin Resistance Nutritional Disease Metabolic Disease

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

PARALLEL

Primary Study Purpose

TREATMENT

Blinding Strategy

SINGLE

Participants

Study Groups

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Placebo1

Placebo Beverage 1 without fiber

Group Type PLACEBO_COMPARATOR

Placebo1

Intervention Type DIETARY_SUPPLEMENT

Placebo Beverage 1 without fiber

Strawberry

Strawberry Beverage 20g/BID

Group Type ACTIVE_COMPARATOR

Strawberry

Intervention Type DIETARY_SUPPLEMENT

20g twice per day (BID) in beverage

Placebo2

Placebo Beverage 2 with Fiber

Group Type PLACEBO_COMPARATOR

Placebo2

Intervention Type DIETARY_SUPPLEMENT

Placebo Beverage 2 with Fiber

Interventions

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Strawberry

20g twice per day (BID) in beverage

Intervention Type DIETARY_SUPPLEMENT

Placebo1

Placebo Beverage 1 without fiber

Intervention Type DIETARY_SUPPLEMENT

Placebo2

Placebo Beverage 2 with Fiber

Intervention Type DIETARY_SUPPLEMENT

Eligibility Criteria

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Inclusion Criteria

* Must meet ONE or MORE of the criteria (1)-(5) associated with insulin resistance along with all other criteria listed (6)-(9):

1. Blood glucose concentration between140-199 mg/dL at 2hr from OGTT.
2. Elevated fasting glucose (110 mg/dL≤ Fasting blood glucose \<126 mg/dL)
3. Elevated fasting insulin (\>75th percentile cutoff of 13.13 μU/mL)
4. Insulin resistance defined by the homeostasis model assessment method of insulin resistance (HOMA-IR) (glucose \[in millimoles per liter\] × insulin \[in microunits per milliliter\]/22.5) values of at least 2.5.
5. Waist circumference ≥ 110 cm because many epidemiology studies have been shown that waist circumferences may be related to insulin resistance.
6. Nonsmokers
7. Not taking any medications that would interfere with outcomes of the study, i.e. lipid lowering medications, anti-inflammatory drugs, or dietary supplements
8. 18 years of age and older
9. No clinical evidence of cardiovascular, metabolic, respiratory, renal, gastrointestinal or hepatic disease

Exclusion Criteria

* Pregnant and/or lactating.

* Allergy or intolerance to strawberries and dairy products.
* Current regular consumption of strawberries is \> 2 servings per day.
* Fasting blood glucose ≥ 126 mg/dL. Subjects identified with elevated fasting blood glucose levels will be advised to contact their primary care physician for appropriate follow-up care.
* Taking over the counter antioxidant supplements or other supplements that may interfere with the study procedures or endpoints.
* Subjects with unusual dietary habits (e.g. pica).
* Actively losing weight or trying to lose weight (unstable body weight fluctuations of \> 5 kg in a 60 day period).
* Excessive exercisers or trained athletes.
* Subjects with documented atherosclerotic disease, inflammatory disease, diabetes mellitus, or other systemic diseases.
* Addicted to drugs and/or alcohol.
* Medically documented psychiatric or neurological disturbances.
* Smoker (past smoker may be allowed if cessation is \> 2 years).
Minimum Eligible Age

18 Years

Maximum Eligible Age

65 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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California Strawberry Commission

OTHER

Sponsor Role collaborator

Clinical Nutrition Research Center, Illinois Institute of Technology

INDUSTRY

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Indika Edirisinghe, Ph.D

Role: PRINCIPAL_INVESTIGATOR

Institute for Food Safety and Health

Britt Burton-Freeman, Ph.D

Role: PRINCIPAL_INVESTIGATOR

Institute for Food Safety and Health

Locations

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Clinical Nutrition Research Center

Chicago, Illinois, United States

Site Status

Countries

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United States

References

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Burton-Freeman B, Linares A, Hyson D, Kappagoda T. Strawberry modulates LDL oxidation and postprandial lipemia in response to high-fat meal in overweight hyperlipidemic men and women. J Am Coll Nutr. 2010 Feb;29(1):46-54. doi: 10.1080/07315724.2010.10719816.

Reference Type RESULT
PMID: 20595645 (View on PubMed)

Edirisinghe I, Burton-Freeman B, Varelis P, Kappagoda T. Strawberry extract caused endothelium-dependent relaxation through the activation of PI3 kinase/Akt. J Agric Food Chem. 2008 Oct 22;56(20):9383-90. doi: 10.1021/jf801864t. Epub 2008 Sep 25.

Reference Type RESULT
PMID: 18816058 (View on PubMed)

Other Identifiers

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STR2 2011-076

Identifier Type: -

Identifier Source: org_study_id

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