Glycemic Index - Variability Among Individuals

This study is currently recruiting participants. (see Contacts and Locations)
Verified May 2014 by Tufts University
Sponsor:
Collaborator:
Information provided by (Responsible Party):
Tufts University
ClinicalTrials.gov Identifier:
NCT01023646
First received: November 30, 2009
Last updated: May 21, 2014
Last verified: May 2014
  Purpose

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.


Condition Intervention
Diabetes
Obesity
Metabolic Syndrome
Cardiovascular Disease
Other: Carbohydrate
Other: Carbohydrate Load
Other: Carbohydrate plus Protein
Other: Carbohydrate plus Fat
Other: Fiber

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Investigator, Outcomes Assessor)
Primary Purpose: Basic Science
Official Title: Evaluation of Glycemic Index to Assess Diet Associated Chronic Disease Risk

Resource links provided by NLM:


Further study details as provided by Tufts University:

Primary Outcome Measures:
  • Glucose, Insulin, Free Fatty Acids. [ Time Frame: 5 hours ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Fasting and non-fasting plasma lipids and lipoproteins, C reactive protein (CRP), HbAIc. [ Time Frame: 5 hours ] [ Designated as safety issue: No ]

Estimated Enrollment: 124
Study Start Date: December 2007
Estimated Study Completion Date: June 2015
Estimated Primary Completion Date: December 2014 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
glycemic index Other: Carbohydrate
Glucose and White bread
Other: Carbohydrate Load
Refined Carbohydrate
Other: Carbohydrate plus Protein
Light Tuna Packed in water.
Other: Carbohydrate plus Fat
Butter
Other: Fiber
Unrefined Carbohydrate

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.

  Eligibility

Ages Eligible for Study:   18 Years to 85 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Criteria

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.
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01023646

Contacts
Contact: Alice H Lichtenstein, D.Sc. 617/556-3127 alice.lichtenstein@tufts.edu

Locations
United States, Massachusetts
Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University Recruiting
Boston, Massachusetts, United States, 02111
Contact: Alice H Lichtenstein, DSc    617-556-3127    alice.lichtenstein@tufts.edu   
Contact: Nirupa R Matthan, PhD    617-556-3114    nirupa.matthan@tufts.edu   
Sub-Investigator: Nirupa R Matthan, PhD         
Sponsors and Collaborators
Tufts University
Investigators
Principal Investigator: Alice H Lichtenstein, D.Sc. JM USDA Human Nutrition Research Center on Aging at Tufts University
  More Information

Publications:
Wolever TMS, Vorster HH, Bjorck I, et al. Determination of the glycemic index of foods:interlaboratory study. European Journal of Clinical Nutrition 2003;57:475-482.

Responsible Party: Tufts University
ClinicalTrials.gov Identifier: NCT01023646     History of Changes
Other Study ID Numbers: RO1DK073321, RO1 DK073321
Study First Received: November 30, 2009
Last Updated: May 21, 2014
Health Authority: United States: Institutional Review Board

Keywords provided by Tufts University:
Glycemic Index
Glycemic Load
Glucose
Insulin
Lipoproteins
Free fatty acids

Additional relevant MeSH terms:
Nutrition Disorders
Cardiovascular Diseases
Obesity
Metabolic Syndrome X
Overnutrition
Overweight
Body Weight
Signs and Symptoms
Insulin Resistance
Hyperinsulinism
Glucose Metabolism Disorders
Metabolic Diseases

ClinicalTrials.gov processed this record on August 28, 2014