Effects of Caffeinated and Decaffeinated Coffee on Body Weight and Glucose Tolerance
Recruitment status was Active, not recruiting
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Purpose
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 | Intervention |
|---|---|
|
Overweight |
Behavioral: Decaffeinated coffee Behavioral: caffeinated coffee |
| Study Type: | Interventional |
| Study Design: | Allocation: Randomized Endpoint Classification: Safety/Efficacy Study Intervention Model: Parallel Assignment Masking: Single Blind (Investigator) Primary Purpose: Prevention |
| Official Title: | Effects of Caffeinated and Decaffeinated Coffee on Body Weight and Glucose Tolerance |
- glucose tolerance / insulin sensitivity [ Time Frame: 4 and 8 weeks ] [ Designated as safety issue: No ]
- body weight/fatness, blood pressure, concentrations of blood lipids, adipokines, inflammatory markers [ Time Frame: 4 and 8 weeks ] [ Designated as safety issue: No ]
| Estimated Enrollment: | 45 |
| Study Start Date: | March 2006 |
| Estimated Study Completion Date: | September 2008 |
| Estimated Primary Completion Date: | September 2008 (Final data collection date for primary outcome measure) |
| Arms | Assigned Interventions |
|---|---|
|
Experimental: 1
Caffeinated coffee
|
Behavioral: caffeinated coffee
5 cups per day for 8 weeks
Other Name: Instant Nestle caffeinated coffee
|
|
Experimental: 2
Decaffeinated coffee
|
Behavioral: Decaffeinated coffee
5 cups per day for 8 weeks
Other Name: Instant Nestle decaffeinated coffee
|
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.
Eligibility| Ages Eligible for Study: | 18 Years and older |
| Genders Eligible for Study: | Both |
| Accepts Healthy Volunteers: | Yes |
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, 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.
Contacts and Locations| United States, Massachusetts | |
| Beth Israel Deaconess Medical Center | |
| Boston, Massachusetts, United States, 02215 | |
| Principal Investigator: | Rob M van Dam, PhD | Harvard School of Public Health |
| Principal Investigator: | Christos Mantzoros, MD | Beth Israel Deaconess Medical Center |
More Information
No publications provided by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
| Responsible Party: | Rob M. van Dam, Harvard School of Public Health |
| ClinicalTrials.gov Identifier: | NCT00305097 History of Changes |
| Other Study ID Numbers: | DK46200 (completed), P30 DK46200 |
| Study First Received: | March 20, 2006 |
| Last Updated: | February 10, 2011 |
| Health Authority: | United States: Federal Government |
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:
|
Body Weight Overweight Signs and Symptoms |
ClinicalTrials.gov processed this record on May 19, 2013