Evaluation of Effects of Green Coffee Bean Extract (GCE) on Physiological and Psychological Variables

Coffee as one of the most favorite worldwide beverages comprises a variety of chemicals with health benefits. Most investigations have so far focused on the beneficial effects of caffeine but knowledge about non-caffeine coffee compounds such as chlorogenic acid (CGA) is scarce. The reducing risk of a variety of diseases following CGA consumption has been mentioned in recent basic and clinical studies. However, there is a lack of studies that examine the behavioral effects of CGA. This study aims to fill this gap. In a randomized double-blind study, the investigators test the acute effects of coffee enriched with CGA or CGA supplement on physiological functions such as blood pressure, blood glucose, and heart rate, and on psychological functions such as mood and cognitive performance in 30 healthy adult subjects (18-40 years). Participants will be allocated to an intervention plan using computer-generated random numbers. Treatments comprise of (1) 6g decaffeinated (5 mg caffeine) coffee (250 ml) with high total CGA (560 mg), or (2) 6g decaffeinated coffee (250 ml) with normal total CGA (224 mg), or (3) 6g decaffeinated coffee (250 ml) with normal total CGA and 800mg green coffee bean extract with total CGA (560mg), or (4) 6g decaffeinated coffee (250 ml) with normal total CGA and placebo, or (5) no treatment group. Upon arrival in the laboratory, participants will complete a 24-hour food recall, a psychometric test battery, and mood and cognitive performance tests. The tests will be repeated 40 min following CGA application, which coincide with the approximated peak of CGA blood concentrations and at 120 min post treatment. Blood pressure, blood glucose and heart rate recordings will be taken prior to treatment and at 1, 30, 60, 90 and 120 min post-treatment. The response to GCE-enriched coffee will be compared to GCE supplement for each of the groups of variables.