The study is a multifaceted approach to investigate the effects of regular consumption of green coffee rich in polyphenols (hydroxycinnamic acids) on weight, body composition, cardiometabolic and inflammatory biomarkers in a sample population of overweight and obese people aimed at identifying a population of responders to green coffee experimenting the highest benefit from this product, and to contribute to the understanding of the influence of some of the main factors on the response to green coffee and their association with the differences between individuals (high-responders vs. low-responders).
A randomized, cross-over, blind clinical trial will be carried out to evaluate the health effects of a polyphenol-rich green (slightly roasted) coffee in comparison with traditional roasted coffee to identify high- and low-responders. Participants will consume the green and roasted coffee in a randomized order during 12 weeks, separated by a 4-week wash-out (and a previous 2-week run-in). Fasting blood samples will be collected in each of the 6 visits to the research centre. Blood pressure and body composition and anthropometric variables will be measured. In addition, urine and fecal samples will be obtained at the beginning and end of each intervention stage to analyze the bioavailability and metabolism of phenolic compounds, and the intestinal microbiota, respectively. Physical activity and energy expenditure will be measured in each of the interventions. Besides a thorough cardiometabolic and inflammatory characterization of the volunteers, the frequency of specific genotypes (related with obesity, energy metabolism, inflammation and coffee intake) will be analyzed, as well as lifestyle and dietary habits of the participants, including aspects such as chrono-nutrition, sleep quality and wellbeing perception with the aim to contribute to clarify the determinants of inter-individual variability in the health effects of coffee bioactive phenolic compounds.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
DOUBLE
Enrollment
120
Each cup of coffee provides approximately 400 mg of hydroxycinnamic acids.
Each cup of coffee provides approximately 150 mg of hydroxycinnamic acids.
Instituto de Ciencia y Tecnología de Alimentos y Nutrición
Madrid, Madrid, Spain
Body weight
Change in body weight (estimated 2.5 kg) at the end of the intervention
Time frame: 12-week
Body fat percentage
Change in body fat percentage (total and visceral) at the end of the intervention
Time frame: 12 weeks
Blood lipids
Change in serum levels of total cholesterol or LDL-cholesterol, HDL-cholesterol or triglycerides at the end of the intervention
Time frame: 12 weeks
Blood glucose
Change in fasting blood glucose levels at the end of the intervention
Time frame: 12 weeks
Insulin levels
Change in fasting blood insulin levels at the end of the intervention
Time frame: 12 weeks
Insulin resistance
Change in homeostasis model assessment (HOMA) of insulin resistance (HOMA-IR) index at the end of the intervention
Time frame: 12 weeks
Insulin sensitivity
Change in quantitative insulin sensitivity check index (QUICKI) at the end of the intervention.
Time frame: 12 weeks
Glycated hemoglobin
Change in blood levels of glycated hemoglobin (HbA1c) at the end of the intervention
Time frame: 12 weeks
Inflammatory cytokines
Change in the levels of the pro-inflammatory cytokines tumor necrosis factor-alpha (TNFa), interleukin (IL)-1beta, IL-2, IL-6, or anti-inflammatory IL-10 at the end of the intervention
Time frame: 12 weeks
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