Clinical trial NCT00305097: Effects of Caffeinated and Decaffeinated Coffee on Body Weight and Glucose Tolerance
Official title: Effects of Caffeinated and Decaffeinated Coffee on Body Weight and Glucose Tolerance
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Overweight
Keywords: coffee
caffeine
glucose tolerance
body weight
insulin sensitivity
randomized controlled trial
Lead sponsor: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Sponsor class: NIH
Collaborators: name: Harvard School of Public Health (HSPH)
name: Beth Israel Deaconess Medical Center
First posted: 2006-03-21
Enrollment: 45
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

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.

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 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.

Primary outcomes:
measure: glucose tolerance / insulin sensitivity
timeFrame: 4 and 8 weeks
Secondary outcomes:
measure: body weight/fatness, blood pressure, concentrations of blood lipids, adipokines, inflammatory markers
timeFrame: 4 and 8 weeks
Other outcomes:
Locations:
city: Boston
country: United States
facility: Beth Israel Deaconess Medical Center
state: Massachusetts
Study officials:
affiliation: Harvard School of Public Health (HSPH)
name: Rob M van Dam, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: Beth Israel Deaconess Medical Center
name: Christos Mantzoros, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Wedick NM, Brennan AM, Sun Q, Hu FB, Mantzoros CS, van Dam RM. Effects of caffeinated and decaffeinated coffee on biological risk factors for type 2 diabetes: a randomized controlled trial. Nutr J. 2011 Sep 13;10:93. doi: 10.1186/1475-2891-10-93.
citation: Peter PR, Park KH, Huh JY, Wedick NM, Mantzoros CS. Circulating irisin levels are not affected by coffee intake: a randomized controlled trial. PLoS One. 2014 Apr 11;9(4):e94463. doi: 10.1371/journal.pone.0094463. eCollection 2014.
citation: Wedick NM, Mantzoros CS, Ding EL, Brennan AM, Rosner B, Rimm EB, Hu FB, van Dam RM. The effects of caffeinated and decaffeinated coffee on sex hormone-binding globulin and endogenous sex hormone levels: a randomized controlled trial. Nutr J. 2012 Oct 19;11:86. doi: 10.1186/1475-2891-11-86.