Glycemic Index - Variability Among Individuals

April 24, 2017 updated by: Tufts University

Evaluation of Glycemic Index to Assess Diet Associated Chronic Disease Risk

The purpose of this study is to determine the variability in glycemic index determinations for individual foods and food combinations. The study will also evaluate the changes in insulin and free fatty acid levels, plasma lipid and lipoprotein profiles, C-reactive protein-a marker of inflammation and glycosylated hemoglobin- a marker of glucose metabolism during a five-hour period after eating the food or foods. Additionally, supplementary data on variation in oral sensation, habitual food intake, food preferences and genes mediating sensory perception and dietary behaviors (supported by a grant from the Tufts Ross Aging Initiative) will be related to the outcomes on the present study.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

The objective of this proposal is to investigate the intra-individual reproducibility (within the same individual, when repeatedly measured) and inter-individual variability (among individuals) of glycemic index (GI) and glycemic load (GL) value determinations for individual foods and food combinations. The specific aims to accomplished this objective are to evaluate reproducibility and variability of GI value determinations in volunteers differing in biologic characteristics - body mass index (BMI), age and gender; assess the effect of macronutrient amounts and combinations, and fiber on variability of GI and GL value determinations; assess the effect of prior meal macronutrient composition ('second meal' effect) on GI value determinations; and relate these data to chronic disease risk factors monitored prior to and during the intervention period. These aims will be accomplished by assessing intra-individual reproducibility and inter-individual variability of repeated GI value determinations for white bread, commonly used as a reference food, relative to glucose, in volunteers selected to represent a range of BMI's (18-24.9, 25-29.9, 30-35) and ages (18-49.9, 50-85 y), and on the basis of gender, and relate these data to body composition and insulin sensitivity (Phase I). This work will then be extended to address issues related to variability potentially introduced by differences in macronutrient and fiber combinations and loads (Phase II), and finally by 'second meal' effects (Phase III). Prior to each set of food challenges (glucose and test food[s] in random order) volunteers will be characterized on the basis of fasting HbA1c; lipids and lipoproteins; insulin, glucose and C-reactive protein. During the 5-hour challenge (sampling at 0, 15, 30, 45, 60, and every 30 minutes thereafter) volunteers will be monitored for changes in blood glucose, insulin, triglycerides, total, low density lipoprotein and high density lipoprotein cholesterol, and non-esterified fatty acid levels. Additionally, supplementary data on variation in oral sensation, habitual food intake, food preferences and genes mediating sensory perception and dietary behaviors (supported by a grant from the Tufts Ross Aging Initiative) will be related to the outcomes on the present study. The concepts of both GI and GL are in the public domain and it has been suggested that the concepts be incorporated into U.S. federal dietary guidance (U.S. Dietary Guidelines and Dietary References Intakes) formulated to promote health and reduce chronic disease risk. This proposal addresses some of the understudied areas for which additional information would be useful in order to determine whether GI and GL should be used to classify foods on an individual basis, as has been suggested, and when formulating dietary guidance for the general population.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Anticipated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
124

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Massachusetts
      • Boston, Massachusetts, United States, 02111
        • Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 85 years (ADULT, OLDER_ADULT)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • For Phase 1 (Study 1) a total of seventy five volunteers will be included in the study. This study will be conducted in adult men and women (18-85 y) free of known chronic disease with BMI 18 to 35 kg/m2.
  • For Phase 2 (Studies 2, 3, 4, and 5) a total of 80 volunteers will be included, 20 volunteers per study. Phase 2 studies will be conducted in adult men and women (50 - 85 y) free of known chronic disease and with a BMI of 25 to 35 kg/m2.
  • For Phase 3 (Study 6) a total of 20 volunteers will be included in the study. Phase 3 study will be conducted in adult men and women (50-85 y) free of known chronic disease and with a BMI of 25 to 35 kg/m2.

Exclusion criteria:

  • BMI ≥ 35 kg/m2 for Phase I, and BMI ≤ 25 to ≥ 35 kg/m2 for Phase II and III
  • Renal disease, as defined by a history of chronic kidney disease or by glomerular filtration rate of < 60 ml.min/1.73 m2 calculated from screening blood tests.
  • Liver disease, as defined by a history of chronic hepatitis B or C, cholestatic or cirrhotic liver disease, nonalcoholic fatty liver disease, elevations of serum glutamate pyruvate transaminase (SGPT) or serum glutamate oxaloacetate transaminase (SGOT) greater than 1.5 times the upper limit of normal at screening, bilirubin greater than 2 mg/dL (in the absence of benign causes of elevated bilirubin such as Gilbert's syndrome) at screening, or albumin below the lower limit of normal.
  • Untreated hypertension, defined as systolic blood pressure (SBP) > 140 mm and diastolic blood pressure (DBP) > 90 mm.
  • Irritable bowel syndrome.
  • Malabsorptive disorder and inflammatory bowel disease.
  • Disorders of esophageal and gastrointestinal motility, and previous esophageal or gastric resection.
  • History of chronic pancreatitis, or history of acute pancreatitis within the last year.
  • Hypothyroidism or hyperthyroidism, as defined as screening thyroid-stimulating hormone (TSH) outside of normal ranges.
  • Anemia, as defined by screening hematocrit of 34% for women and 38% for men.
  • Smoking within the past 6 months.
  • Diabetes.
  • Fasting glucose ≥ 125 mg/dL.
  • Pregnancy.
  • Breastfeeding.
  • History of polycystic ovary syndrome
  • History of autoimmune or other connective tissue disorders associated with chronic inflammation, such as rheumatoid arthritis.
  • Alcohol consumption > 7 drinks/week.
  • Use of medications or supplements known to affect glucose metabolism.
  • Use of medications or supplements known to affect lipid metabolism.
  • Established cardiovascular disease (myocardial infarction, stroke, heart failure, coronary artery. bypass graft, stenosis > 50%, peripheral arterial disease).
  • Unwillingness to adhere to study protocol.
  • Weight gain or loss of more than 15 lbs within 6 months prior to enrollment.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: BASIC_SCIENCE
  • Allocation: RANDOMIZED
  • Interventional Model: CROSSOVER
  • Masking: DOUBLE

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
OTHER: carbohydrate load
Food challenge - Carbohydrate load
Other: Carbohydrate load
Carbohydrate
OTHER: Carbohydrate + Protein
Food challenge - carbohydrate + protein
Other: Carbohydrate + Protein
Light Tuna Packed in water.
OTHER: Carbohydrate + Fat
Food challenge - carbohydrate + fat
Other: Carbohydrate + Fat
Butter
OTHER: Fiber
Food challenge - carbohydrate + fiber
Other: Fiber
Unrefined Carbohydrate

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Time Frame
Glucose, Insulin, Free Fatty Acids.
Time Frame: 5 hours
5 hours

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Time Frame
Fasting and non-fasting plasma lipids and lipoproteins, C reactive protein (CRP), HbAIc.
Time Frame: 5 hours
5 hours

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Tufts University

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Alice H Lichtenstein, D.Sc., JM USDA Human Nutrition Research Center on Aging at Tufts University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
December 1, 2007

Primary Completion (ACTUAL)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2015

Study Completion (ACTUAL)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2016

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
November 30, 2009

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 1, 2009

First Posted (ESTIMATE)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
December 2, 2009

Study Record Updates

Last Update Posted (ACTUAL)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 25, 2017

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 24, 2017

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2017

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • R01DK073321 (NIH)

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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