Glucose Tolerance, Meal Timing and MTNR1B
Condition: Non-Diabetic Disorder of Endocrine Pancreas
Study type: Interventional

Summary: 
      The purpose of this investigation is to assess in a community-based cohort of late-night
      eaters the effect of coincident food intake and endogenous melatonin on glycemic control, and
      the putative interaction effect of melatonin receptor 1B (MTNR1B) genetic variation on this
      relationship. With the results from this study, the investigators expect to advance in the
      understanding of the role of endogenous melatonin on glucose metabolism in late night eaters
      and carriers of the MTNR1B risk allele, with potential implications on the guidelines to
      mitigate risk of type 2 diabetes in late night eaters and carriers of the MTNR1B risk allele.
    

Detailed description: 
      Late-night dinner eating is associated with increased risk for type-2-diabetes. The
      underlying mechanism is unclear. One explanatory hypothesis is that the concurrence of
      elevated circulating melatonin and high glucose concentrations (characterizing late-eating)
      leads to impaired glucose-tolerance. However, to date, no study has tested the influence of
      physiological melatonin concentrations on glucose tolerance. The discovery of melatonin
      receptor MTNR1B as a diabetes risk gene provides evidence for a role of physiological levels
      of melatonin in glucose control.

      The aim of the current study is to test the hypothesis that the concurrence of meal timing
      with elevated endogenous melatonin concentrations results in impaired glucose control and
      that this effect is stronger in homozygous MTNR1B risk carriers than in non-carriers. To do
      so we will test glucose tolerance using identical mixed meals under two dinner conditions: a)
      delayed dinner or Late Eating (LE): starting1 hour before usual bed time, b) advanced dinner
      or Early Eating (EE): starting 4 hours before habitual bed time, in a randomized, cross-over
      study design.

      These findings could support a clinical application for the screening of this single
      nucleotide polymorphism (SNP) and the possibility of implementing tailored and cost-effective
      behavioral interventions to prevent type 2 diabetes in vulnerable populations.

      These goals will be achieved through a specific approach:

      • Interventional (randomized, cross-over controlled trials) (Aim 1): To study the potential
      interaction between meal timing (dinner) and genetic variants MTNR1B for glucose tolerance.
    

Intervention name(s): Dinner timing
Intervention type(s): Behavioral
Intervention description(s): Glucose tolerance after a late diner (1 hour before habitual bedtime) differs from early dinner (4 hours before habitual bedtime) due to the concurrence of meal timing with different levels of endogenous melatonin. This effect can be different among risk allele carriers (G) or non-rick allele carriers (C) of the MTNR1B.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Prevention
Keywords: Glucose tolerance; MTNR1B; nutrigenomics; Food timing