Overview

This trial is active, not recruiting.

Condition overweight
Treatments decaffeinated coffee, caffeinated coffee
Sponsor National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Start date March 2006
End date September 2008
Trial size 45 participants
Trial identifier NCT00305097, DK46200 (completed), P30 DK46200

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.

United States No locations recruiting
Other Countries No locations recruiting

Study Design

Allocation randomized
Endpoint classification safety/efficacy study
Intervention model parallel assignment
Masking single blind (investigator)
Primary purpose prevention
Arm
(Experimental)
Caffeinated coffee
caffeinated coffee Instant Nestle caffeinated coffee
5 cups per day for 8 weeks
(Experimental)
Decaffeinated coffee
decaffeinated coffee Instant Nestle decaffeinated coffee
5 cups per day for 8 weeks

Primary Outcomes

Measure
glucose tolerance / insulin sensitivity
time frame: 4 and 8 weeks

Secondary Outcomes

Measure
body weight/fatness, blood pressure, concentrations of blood lipids, adipokines, inflammatory markers
time frame: 4 and 8 weeks

Eligibility Criteria

Male or female participants at least 18 years old.

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.

Additional Information

Official title Effects of Caffeinated and Decaffeinated Coffee on Body Weight and Glucose Tolerance
Principal investigator Rob M van Dam, PhD
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.
Trial information was received from ClinicalTrials.gov and was last updated in February 2011.
Information provided to ClinicalTrials.gov by National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK).