Clinical trial NCT01064778: Glycemic Index and Brain Function
Official title: The Effects of Dietary Glycemic Index on Brain Function
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Obesity
Keywords: Glycemic Index
Brain
Intake Regulation
Weight Loss
Hunger
Diet
Lead sponsor: Beth Israel Deaconess Medical Center
Sponsor class: OTHER
Collaborators: name: Boston Children's Hospital
name: Brigham and Women's Hospital
First posted: 2010-02-08
Enrollment: 12
Sex: MALE
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: TREATMENT

Brief summary: 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.

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 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

Primary outcomes:
measure: Blood Flow in Brain Areas of Intake Control.
timeFrame: 4 hours postprandial
Secondary outcomes:
measure: Subjective Hunger Rating
timeFrame: Every 30 minutes for 5 hours.
measure: Blood Glucose Level
timeFrame: Every 30 minutes for 5 hours.
measure: Blood Insulin Level
timeFrame: Every 30 minutes for 5 hours
measure: Blood Glucagon Level
timeFrame: Every 30 minutes for 5 hours.
measure: Blood Growth Hormone Level
timeFrame: Every 30 minutes for 5 hours.
measure: Blood Epinephrine Level
timeFrame: Every 30 minutes for 5 hours.
measure: Blood Fatty Acids Level
timeFrame: Every 30 minutes for 5 hours.
Other outcomes:
Locations:
city: Boston
country: United States
facility: Children's Hospital Boston
state: Massachusetts
city: Boston
country: United States
facility: Beth Israel Deaconess Medical Center
state: Massachusetts
city: Boston
country: United States
facility: Brigham and Women's Hospital
state: Massachusetts
Study officials:
affiliation: Boston Children's Hospital
name: David S Ludwig, MD, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: Beth Israel Deaconess Medical Center
name: David Alsop, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: Boston Children's Hospital
name: Belinda S Lennerz, MD, PhD
role: STUDY_DIRECTOR
References:
citation: Lennerz BS, Alsop DC, Holsen LM, Stern E, Rojas R, Ebbeling CB, Goldstein JM, Ludwig DS. Effects of dietary glycemic index on brain regions related to reward and craving in men. Am J Clin Nutr. 2013 Sep;98(3):641-7. doi: 10.3945/ajcn.113.064113. Epub 2013 Jun 26.