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Glycemic Index and Brain Function

1. februar 2012 oppdatert av: David Alsop, Beth Israel Deaconess Medical Center

The Effects of Dietary Glycemic Index on Brain Function

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.

Studieoversikt

Status

Fullført

Forhold

Intervensjon / Behandling

Detaljert beskrivelse

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.

Studietype

Intervensjonell

Registrering (Faktiske)

12

Fase

  • Ikke aktuelt

Kontakter og plasseringer

Denne delen inneholder kontaktinformasjon for de som utfører studien, og informasjon om hvor denne studien blir utført.

Studiesteder

  • Forente stater
    • Massachusetts
      • Boston, Massachusetts, Forente stater, 02215
        • Beth Israel Deaconess Medical Center
      • Boston, Massachusetts, Forente stater, 02115
        • Children's Hospital Boston
      • Boston, Massachusetts, Forente stater, 02215
        • Brigham and Women's Hospital

Deltakelseskriterier

Forskere ser etter personer som passer til en bestemt beskrivelse, kalt kvalifikasjonskriterier. Noen eksempler på disse kriteriene er en persons generelle helsetilstand eller tidligere behandlinger.

Kvalifikasjonskriterier

Alder som er kvalifisert for studier

18 år til 35 år (Voksen)

Tar imot friske frivillige

Ja

Kjønn som er kvalifisert for studier

Mann

Beskrivelse

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

Studieplan

Denne delen gir detaljer om studieplanen, inkludert hvordan studien er utformet og hva studien måler.

Hvordan er studiet utformet?

Designdetaljer

  • Primært formål: Behandling
  • Tildeling: Randomisert
  • Intervensjonsmodell: Crossover-oppdrag
  • Masking: Firemannsrom

Våpen og intervensjoner

Deltakergruppe / Arm
Intervensjon / Behandling
Aktiv komparator: Low GI
Annen: 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.
Eksperimentell: High GI
Annen: 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.

Hva måler studien?

Primære resultatmål

Resultatmål
Tidsramme
Blood Flow in Brain Areas of Intake Control.
Tidsramme: 4 hours postprandial
4 hours postprandial

Sekundære resultatmål

Resultatmål
Tiltaksbeskrivelse
Tidsramme
Subjective Hunger Rating
Tidsramme: Every 30 minutes for 5 hours.
Every 30 minutes for 5 hours.
Blood Glucose Level
Tidsramme: Every 30 minutes for 5 hours.
Every 30 minutes for 5 hours.
Blood Insulin Level
Tidsramme: Every 30 minutes for 5 hours
Every 30 minutes for 5 hours
Blood Glucagon Level
Tidsramme: Every 30 minutes for 5 hours.
Every 30 minutes for 5 hours.
Blood Growth Hormone Level
Tidsramme: Every 30 minutes for 5 hours.
Every 30 minutes for 5 hours.
Blood Epinephrine Level
Tidsramme: Every 30 minutes for 5 hours.
Every 30 minutes for 5 hours.
Blood Fatty Acids Level
Tidsramme: Every 30 minutes for 5 hours.
measuring metabolite profiles
Every 30 minutes for 5 hours.

Samarbeidspartnere og etterforskere

Det er her du vil finne personer og organisasjoner som er involvert i denne studien.

Sponsor

Beth Israel Deaconess Medical Center

Samarbeidspartnere

Boston Children's Hospital
Brigham and Women's Hospital

Etterforskere

  • Studieleder: Belinda S Lennerz, MD, PhD, Boston Children's Hospital
  • Hovedetterforsker: David Alsop, PhD, Beth Israel Deaconess Medical Center

Publikasjoner og nyttige lenker

Den som er ansvarlig for å legge inn informasjon om studien leverer frivillig disse publikasjonene. Disse kan handle om alt relatert til studiet.

Generelle publikasjoner

Studierekorddatoer

Disse datoene sporer fremdriften for innsending av studieposter og sammendragsresultater til ClinicalTrials.gov. Studieposter og rapporterte resultater gjennomgås av National Library of Medicine (NLM) for å sikre at de oppfyller spesifikke kvalitetskontrollstandarder før de legges ut på det offentlige nettstedet.

Studer hoveddatoer

Studiestart

1. februar 2010

Primær fullføring (Faktiske)

1. juni 2011

Studiet fullført (Faktiske)

1. september 2011

Datoer for studieregistrering

Først innsendt

5. februar 2010

Først innsendt som oppfylte QC-kriteriene

5. februar 2010

Først lagt ut (Anslag)

8. februar 2010

Oppdateringer av studieposter

Sist oppdatering lagt ut (Anslag)

2. februar 2012

Siste oppdatering sendt inn som oppfylte QC-kriteriene

1. februar 2012

Sist bekreftet

1. februar 2012

Mer informasjon

Begreper knyttet til denne studien

Nøkkelord

Andre studie-ID-numre

  • RA-003

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