Glycemic Index and Brain Function

This study has been completed.
Sponsor:
Collaborators:
Children's Hospital Boston
Brigham and Women's Hospital
Information provided by (Responsible Party):
David Alsop, Beth Israel Deaconess Medical Center
ClinicalTrials.gov Identifier:
NCT01064778
First received: February 5, 2010
Last updated: February 1, 2012
Last verified: February 2012
  Purpose

The investigators propose examine the effects of the dietary factor glycemic index (GI) on brain areas that control food intake and hunger. This knowledge could help design dietary approaches that decrease hunger, and thus promote new weight loss strategies.


Condition Intervention
Obesity
Other: Low GI
Other: High GI

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: The Effects of Dietary Glycemic Index on Brain Function

Resource links provided by NLM:


Further study details as provided by Beth Israel Deaconess Medical Center:

Primary Outcome Measures:
  • Blood Flow in Brain Areas of Intake Control. [ Time Frame: 4 hours postprandial ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • Subjective Hunger Rating [ Time Frame: Every 30 minutes for 5 hours. ] [ Designated as safety issue: No ]
  • Blood Glucose Level [ Time Frame: Every 30 minutes for 5 hours. ] [ Designated as safety issue: No ]
  • Blood Insulin Level [ Time Frame: Every 30 minutes for 5 hours ] [ Designated as safety issue: No ]
  • Blood Glucagon Level [ Time Frame: Every 30 minutes for 5 hours. ] [ Designated as safety issue: No ]
  • Blood Growth Hormone Level [ Time Frame: Every 30 minutes for 5 hours. ] [ Designated as safety issue: No ]
  • Blood Epinephrine Level [ Time Frame: Every 30 minutes for 5 hours. ] [ Designated as safety issue: No ]
  • Blood Fatty Acids Level [ Time Frame: Every 30 minutes for 5 hours. ] [ Designated as safety issue: No ]
    measuring metabolite profiles


Enrollment: 12
Study Start Date: February 2010
Study Completion Date: September 2011
Primary Completion Date: June 2011 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: Low GI Other: Low GI
Subjects will be instructed to consume a liquid test meal with a low GI over 5 minutes after baseline laboratory evaluations. The low and high GI meal contain similar amounts of milk, oil, dried egg whites, equal, and vanilla extract. The low GI meal corn-starch as a carbohydrate. Both meals have similar macronutrient composition (60% carbohydrate, 15% protein, 25% fat), micronutrient profiles, physical properties, palatability and sweetness. The high vs. low GI meals have a predicted difference in GI of 90 vs. 40, and consistent with this prediction, a pilot study in obese young adults found a 2.2-fold difference in glycemic response (p<0.001). The test meals will provide 25% of individual daily energy requirements.
Experimental: High GI Other: High GI
Subjects will be instructed to consume a liquid test meal with a high GI over 5 minutes after baseline laboratory evaluations. The low and high GI meal contain similar amounts of milk, oil, dried egg whites, equal, and vanilla extract. The high GI meal contains corn-syrup as a carbohydrate. Both meals have similar macronutrient composition (60% carbohydrate, 15% protein, 25% fat), micronutrient profiles, physical properties, palatability and sweetness. The high vs. low GI meals have a predicted difference in GI of 90 vs. 40, and consistent with this prediction, a pilot study in obese young adults found a 2.2-fold difference in glycemic response (p<0.001). The test meals will provide 25% of individual daily energy requirements.

Detailed Description:

Most individuals have great difficulty following reduced calorie diets because they experience increased hunger. This process is regulated by specific brain areas. Though many psychological and environmental factors are involved, physiological effects of diet may have a significant impact. The postprandial rise in blood glucose, quantified by the glycemic index (GI), is of particular interest. High GI meals elicit hormonal events that limit availability of metabolic fuels, causing hunger and overeating, especially in people with high insulin secretion.

Our aim is to examine how postprandial changes after high versus low GI meals affect hunger and brain function in areas of intake control. Specifically, we speculate that obese individuals will demonstrate functional changes in brain areas of intake control and increased hunger after a high versus low GI meal.

We will recruit obese, young adults and quantify their insulin secretion during a 2-hour oral glucose tolerance test. A brief practice MRI session will serve to familiarize the subjects with the scanning process. During the two test sessions, standardized test meals with high versus low GI will be given in a randomized, blinded cross-over design. Serial blood levels of hormones, metabolic fuels, and metabolites will be correlated with perceived hunger, and a perfusion MRI scan will be performed to assess brain activation during the late postprandial phase, at the nadir of blood sugar and insulin levels (4 hours postprandial).

This work will inform an integrated physiological model relating peripheral postprandial changes to brain function and hunger. In addition, findings may provide evidence of a novel diet-phenotype, in which baseline clinical characteristics can be used to predict which weight loss diet will work best for a specific individual. Metabolite profiling might shed light on the mechanisms linking diet composition to brain function, and provide feasible clinical markers of the identified phenotype to facilitate translation into practice.

  Eligibility

Ages Eligible for Study:   18 Years to 35 Years
Genders Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion criteria

  1. Males age 18 to 35 years
  2. BMI less than or equal to 25 for age and gender

Exclusion criteria

  1. weight > 300 lbs
  2. largest body circumference > 144cm
  3. body shape incompatible with MRI scanner or equipment
  4. MRI exclusion criteria
  5. large fluctuations in body weight (5% over preceding 6 months, 2.5% during the study)
  6. known medical problems that may affect metabolism or hormones
  7. diabetes mellitus (fasting plasma glucose ≥126 mg/dL)
  8. other abnormal laboratory screening tests
  9. taking any medications or dietary supplements that might affect body weight, appetite, or energy expenditure
  10. smoking or illicit substance abuse
  11. high levels of physical activity (>30 minutes per day, > 4days per week)
  12. currently following a weight loss diet
  13. allergies or intolerance to eggs, vanilla extract, equal, canola oil, milk, cornstarch, corn syrup
  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: NCT01064778

Locations
United States, Massachusetts
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States, 02215
Brigham and Women's Hospital
Boston, Massachusetts, United States, 02215
Children's Hospital Boston
Boston, Massachusetts, United States, 02115
Sponsors and Collaborators
Beth Israel Deaconess Medical Center
Children's Hospital Boston
Brigham and Women's Hospital
Investigators
Principal Investigator: David S Ludwig, MD, PhD Children's Hospital Boston
Principal Investigator: David Alsop, PhD Beth Israel Deaconess Medical Center
Study Director: Belinda S Lennerz, MD, PhD Children's Hospital Boston
  More Information

No publications provided by Beth Israel Deaconess Medical Center

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: David Alsop, Director of MRI Research, Beth Israel Deaconess Medical Center
ClinicalTrials.gov Identifier: NCT01064778     History of Changes
Other Study ID Numbers: RA-003
Study First Received: February 5, 2010
Last Updated: February 1, 2012
Health Authority: United States: Institutional Review Board

Keywords provided by Beth Israel Deaconess Medical Center:
Glycemic Index
Brain
Intake Regulation
Weight Loss
Hunger
Diet

Additional relevant MeSH terms:
Obesity
Overnutrition
Nutrition Disorders
Overweight
Body Weight
Signs and Symptoms

ClinicalTrials.gov processed this record on July 26, 2014