Observational Study of Blood Glucose Levels and Gut Microbiota in Healthy Individuals

This study is currently recruiting participants. (see Contacts and Locations)
Verified July 2013 by Tel-Aviv Sourasky Medical Center
Sponsor:
Collaborator:
Weizmann Institute of Science
Information provided by (Responsible Party):
Tel-Aviv Sourasky Medical Center
ClinicalTrials.gov Identifier:
NCT01892956
First received: May 26, 2013
Last updated: March 26, 2014
Last verified: July 2013
  Purpose

Categorization of glucose levels into 'healthy', 'pre-diabetic' or 'diabetic' is increasingly seen as artificial. Furthermore, most micro and macrovascular complications may be present already at the pre-diabetic stage.

Hyperglycemia, pre-diabetes and impaired glucose tolerance (IGT) are fully reversible, thus, maintaining normal blood sugar levels is crucial for the prevention and control of diabetes and the various other consequences of the metabolic syndrome. Only interventions that are individually tailored can achieve proper glycemic control, and the glycemic index (GI), which quantifies the glycemic response to particular foods, was developed for this purpose.

In this study the investigators will characterize the blood glucose responses and microbiota of healthy individuals, aiming to assess the influence of food intake on gut microbiota and the influence of gut microbiota on glycemic responses.


Condition
Nutritional and Metabolic Diseases
Endocrine System Diseases
Disorders of Environmental Origin

Study Type: Observational
Study Design: Observational Model: Case-Only
Time Perspective: Prospective
Official Title: Observational Study of Blood Glucose Levels and Gut Microbiota in Healthy Individuals

Resource links provided by NLM:


Further study details as provided by Tel-Aviv Sourasky Medical Center:

Primary Outcome Measures:
  • Blood glucose levels [ Time Frame: One week ] [ Designated as safety issue: No ]

Secondary Outcome Measures:
  • DNA sequencing of the gut microbiota composition [ Time Frame: Before or during the glucose testing week ] [ Designated as safety issue: No ]

Biospecimen Retention:   Samples Without DNA

Blood count, lipids, liver functions, CBP Stool sample for intestinal microbiota


Estimated Enrollment: 2000
Study Start Date: April 2013
Estimated Study Completion Date: April 2016
Estimated Primary Completion Date: April 2015 (Final data collection date for primary outcome measure)
Groups/Cohorts
Healthy volunteers

Detailed Description:

Advances in characterization and diagnosis of type 2 Diabetes Mellitus (T2DM) led to the identification of a rapidly growing number of individuals who fall under a 'gray zone' of disturbed yet non-diabetic fasting or post-prandial glucose levels, termed pre-diabetes, impaired glucose tolerance (IGT), or simply individuals with fasting or post-prandial glucose levels in the upper-normal range. All of these poorly characterized groups are at substantial risk for long-term medical complications. Consequently, categorization of glucose levels into 'healthy', 'pre-diabetic' or 'diabetic' is increasingly seen as artificial, and both glucose levels and risk of diabetes are considered as continuous variables. In the past three decades, glucose levels have been rapidly increasing in the overall population in developed and developing countries alike, resulting in a sharp incline in the prevalence of both pre-diabetes and IGT. In the U.S. alone, the estimates are that 79 million people have been affected by 2010, and the projections suggest that 472 million people will be affected worldwide by 2030. Up to 70-90% of those individuals with IGT or pre-diabetes proceed to develop full-blown T2DM. Furthermore, most micro and macrovascular complications, including chronic renal disease, sensory and autonomic neuropathy and diabetic retinopathy, may be present already at the pre-diabetic stage. In addition, pre-diabetic hyperglycemia is linked to multiple manifestations of the metabolic syndrome, such as obesity, hypertension and hypertriglyceridemia, and is an independent risk factor for major macrovascular events such as coronary heart disease and total vascular mortality. Despite these serious risks, and in striking contrast to overt diabetes, hyperglycemia, pre-diabetes and IGT are fully reversible, with up to 55- 80% of individuals reported to revert to normoglycemia and normoinsulinemia upon life-style modifications. Thus, maintaining normal blood sugar levels is crucial for the prevention and control of diabetes and the various other consequences of the metabolic syndrome. The glycemic index (GI), which quantifies the glycemic response to particular foods, was developed for this purpose, but low GI diets have poor predictive value for T2DM development in both the healthy and pre-diabetic settings. This limited success of the GI index may be an inherent problem to any method that assigns a single value to a given food, since individuals vary greatly in their glycemic response to the same food, and even the nature of variation is currently poorly characterized. Along these lines, emerging data from our group and others strongly suggest that proper control and modulation of the glycemic response to foods relies on person-specific factors and thus, only interventions that are individually tailored can achieve proper glycemic control. Although variations in host-related genetic factors affect the normal and post-prandial glycemic response, these factors are estimated to account for only ~10% of the metabolic phenotype. This low estimate is reinforced by the growing incidence of diabetes in recent years. In contrast, increasing importance in glucose homeostasis is being attributed to environmental factors such as the composition and function of the cumulative intestinal microbiota. This immense and poorly understood ecosystem of over 1500 species of bacteria, fungi, and their viruses are modulated by diet, and in turn, profoundly regulate host metabolic processes. Evidence for this host-microbiota interplay includes a distinct microbiota composition found in T2DM patients; and numerous alterations in the microbiome composition and expression of major metabolic pathways found one day after switching from a plant polysaccharide-based diet to a sugary "western" diet in germ-free mice inoculated with a human microbiota. Furthermore, microbiota-induced local gut inflammation was recently linked to a propensity for glucose intolerance, which was reversible upon antibiotic treatment. In this study the investigators will characterize the blood glucose responses and microbiota of healthy individuals, aiming to assess the influence of food intake on gut microbiota and the influence of gut microbiota on glycemic responses.

  Eligibility

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

Israeli residents and visitors

Criteria

Inclusion Criteria:

  • Healthy adults

Exclusion Criteria:

  • Under 18 years of age
  • Mental incompetence.
  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: NCT01892956

Contacts
Contact: Zamir Halpern, MD 972-36974282 halpernza@tlvmc.gov.il

Locations
Israel
Gastroenterology Institute Recruiting
Tel-Aviv, Israel, 64239
Contact: Noya Horowitz, PhD    972-3-6974297    noyah@tlvmc.gov.il   
Principal Investigator: Zamir Halpern, MD         
Sub-Investigator: Eran Elinav, PhD         
Sub-Investigator: Eran Segal, PhD         
Sponsors and Collaborators
Tel-Aviv Sourasky Medical Center
Weizmann Institute of Science
Investigators
Principal Investigator: Zamir Halpern, MD Tel-Aviv Sourasky Medical Center
  More Information

No publications provided

Responsible Party: Tel-Aviv Sourasky Medical Center
ClinicalTrials.gov Identifier: NCT01892956     History of Changes
Other Study ID Numbers: TASMC-12-ZH-658
Study First Received: May 26, 2013
Last Updated: March 26, 2014
Health Authority: Israel: Ministry of Health

Additional relevant MeSH terms:
Metabolic Diseases
Endocrine System Diseases

ClinicalTrials.gov processed this record on September 30, 2014