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Effects of Caffeinated and Decaffeinated Coffee on Body Weight and Glucose Tolerance

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ClinicalTrials.gov Identifier: NCT00305097
Recruitment Status : Completed
First Posted : March 21, 2006
Last Update Posted : March 6, 2018
Sponsor:
Collaborators:
Harvard School of Public Health
Beth Israel Deaconess Medical Center
Information provided by (Responsible Party):
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Brief Summary:
Habitual consumption of coffee may have substantial beneficial effects on glucose metabolism according to recent findings of epidemiological studies in the U.S., Europe, and Japan. However, data from longer-term human intervention studies with appropriate outcome measures are lacking. We will study the effects of caffeinated and decaffeinated coffee consumption on body fatness, insulin sensitivity and glucose tolerance that may underlie the observed associations with a lower risk of type 2 diabetes in a randomized controlled trial. We hypothesize that both caffeinated and decaffeinated coffee will improve insulin sensitivity and glucose tolerance. Before starting a larger, long-term intervention study, we will conduct a pilot study to test the feasibility of such a trial. The pilot study will be an 8-week parallel trial in 45 overweight individuals, who will be randomized to drinking 5 cups per day of 1) caffeinated coffee (n=15), 2) decaffeinated coffee (n=15), or 3) water (n=15). Body fatness (weight, waist circumference, bioelectrical impedance), insulin sensitivity (HOMA model), and glucose tolerance (oral glucose tolerance test) will be the primary outcomes. We will assess the adherence of participants to their assigned treatment by measuring serum caffeine concentrations, documentation of coffee use in diaries by the participants, and counting unused coffee packets. We will also obtain feedback from participants on how to improve compliance in a future trial. If successful, this study will form the basis for a definitive trial of coffee consumption, body fatness, and glucose tolerance. Given the extensive use of coffee and the rapidly increasing health burden of type 2 diabetes, such a trial would have important public health implications.

Condition or disease Intervention/treatment Phase
Overweight Dietary Supplement: Decaffeinated coffee Dietary Supplement: Caffeinated coffee Dietary Supplement: No coffee Not Applicable

Detailed Description:
Habitual consumption of coffee may have substantial beneficial effects on glucose metabolism according to recent findings of epidemiological studies in the U.S., Europe, and Japan. However, data from longer-term human intervention studies with appropriate outcome measures are lacking. We will study the effects of caffeinated and decaffeinated coffee consumption on body fatness, insulin sensitivity and glucose tolerance that may underlie the observed associations with a lower risk of type 2 diabetes in a randomized controlled trial. We hypothesize that both caffeinated and decaffeinated coffee will improve insulin sensitivity and glucose tolerance. Before starting a larger, long-term intervention study, we will conduct a pilot study to test the feasibility of such a trial. The pilot study will be an 8-week parallel trial in 45 overweight individuals, who will be randomized to drinking 5 cups per day of 1) caffeinated coffee (n=15), 2) decaffeinated coffee (n=15), or 3) water (n=15). Body fatness (weight, waist circumference, bioelectrical impedance), insulin sensitivity (HOMA model), and glucose tolerance (oral glucose tolerance test) will be the primary outcomes. We will assess the adherence of participants to their assigned treatment by measuring serum caffeine concentrations, documentation of coffee use in diaries by the participants, and counting unused coffee packets. We will also obtain feedback from participants on how to improve compliance in a future trial. If successful, this study will form the basis for a definitive trial of coffee consumption, body fatness, and glucose tolerance. Given the extensive use of coffee and the rapidly increasing health burden of type 2 diabetes, such a trial would have important public health implications.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 45 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single (Investigator)
Primary Purpose: Prevention
Official Title: Effects of Caffeinated and Decaffeinated Coffee on Body Weight and Glucose Tolerance
Actual Study Start Date : May 2006
Actual Primary Completion Date : September 2008
Actual Study Completion Date : September 2008

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Body Weight

Arm Intervention/treatment
Experimental: Caffeinated coffee
Caffeinated coffee
Dietary Supplement: Caffeinated coffee
5 cups per day for 8 weeks
Other Name: Instant Nestle caffeinated coffee

Experimental: Decaffeinated coffee
Decaffeinated coffee
Dietary Supplement: Decaffeinated coffee
5 cups per day for 8 weeks
Other Name: Instant Nestle decaffeinated coffee

Active Comparator: No coffee Dietary Supplement: No coffee



Primary Outcome Measures :
  1. glucose tolerance / insulin sensitivity [ Time Frame: 4 and 8 weeks ]

Secondary Outcome Measures :
  1. body weight/fatness, blood pressure, concentrations of blood lipids, adipokines, inflammatory markers [ Time Frame: 4 and 8 weeks ]


Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Aged at least 18 years with an ability and willingness to give written informed consent.
  • Body mass index 25-35 kg/m2
  • Users of at least 2 cups of caffeinated coffee per day who are willing to be randomized to any of the interventions.
  • Non-smoking

Exclusion Criteria:

  • Any condition/illness that may affect the study outcomes or would make participation potentially harmful such as pregnancy or breastfeeding, diabetes mellitus, heart disease, stroke, hypertension, malabsorption syndromes, Gastroesophageal reflux disease GERD, a history of ulcer, according to a detailed medical history.
  • Abnormal hepatic function (liver function test > twice the normal range), abnormal renal function (creatinine > 1.1 mg/dl), fasting plasma glucose in the diabetic range (>/= 126 mg/dl), or blood pressure > 140/90 mmHg.
  • Present alcoholism or drug abuse or use of medications that could interfere with the treatment including bronchodilators, quinolone antibiotics, monoamine oxidase inhibitors, anxiolytics, ranitidine, corticosteroids, growth hormone, antihypertensives.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00305097


Locations
United States, Massachusetts
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States, 02215
Sponsors and Collaborators
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Harvard School of Public Health
Beth Israel Deaconess Medical Center
Investigators
Principal Investigator: Rob M van Dam, PhD Harvard School of Public Health
Principal Investigator: Christos Mantzoros, MD Beth Israel Deaconess Medical Center

Publications of Results:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
ClinicalTrials.gov Identifier: NCT00305097     History of Changes
Other Study ID Numbers: DK46200 (completed)
P30DK046200 ( U.S. NIH Grant/Contract )
First Posted: March 21, 2006    Key Record Dates
Last Update Posted: March 6, 2018
Last Verified: March 2018

Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No

Keywords provided by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK):
coffee
caffeine
glucose tolerance
body weight
insulin sensitivity
randomized controlled trial

Additional relevant MeSH terms:
Overweight
Body Weight
Signs and Symptoms