The Pocket-4-Life project, bioavailability and beneficial properties of the bioactive compounds of espresso coffee and cocoa-based confectionery containing coffee: study protocol for a randomized cross-over trial

Abstract

BackgroundCoffee is an important source of bioactive compounds, including caffeine, phenolic compounds (mainly chlorogenic acids), trigonelline, and diterpenes. Several studies have highlighted the preventive effects of coffee consumption on major cardiometabolic diseases, but the impact of coffee dosage on markers of cardiometabolic risk is not well understood. Moreover, the pool of coffee-derived circulating metabolites and the contribution of each metabolite to disease prevention still need to be evaluated in real-life settings. The aim of this study will be to define the bioavailability and beneficial properties of coffee bioactive compounds on the basis of different levels of consumption, by using an innovative experimental design. The contribution of cocoa-based products containing coffee to the pool of circulating metabolites and their putative bioactivity will also be investigated.MethodsA three-arm, crossover, randomized trial will be conducted. Twenty-one volunteers will be randomly assigned to consume three treatments in a random order for 1 month: 1 cup of espresso coffee/day, 3 cups of espresso coffee/day, and 1 cup of espresso coffee plus 2 cocoa-based products containing coffee twice per day. The last day of each treatment, blood and urine samples will be collected at specific time points, up to 24 hours following the consumption of the first product. At the end of each treatment the same protocol will be repeated, switching the allocation group. Besides the bioavailability of the coffee/cocoa bioactive compounds, the effect of the coffee/cocoa consumption on several cardiometabolic risk factors (anthropometric measures, blood pressure, inflammatory markers, trimethylamine N-oxide, nitric oxide, blood lipids, fasting indices of glucose/insulin metabolism, DNA damage, eicosanoids, and nutri-metabolomics) will be investigated.DiscussionResults will provide information on the bioavailability of the main groups of phytochemicals in coffee and on their modulation by the level of consumption. Findings will also show the circulating metabolites and their bioactivity when coffee consumption is substituted with the intake of cocoa-based products containing coffee. Finally, the effect of different levels of 1-month coffee consumption on cardiometabolic risk factors will be elucidated, likely providing additional insights on the role of coffee in the protection against chronic diseases.Trial registrationClinicalTrials.gov, NCT03166540. Registered on May 21, 2017.Electronic supplementary materialThe online version of this article (doi:10.1186/s13063-017-2271-2) contains supplementary material, which is available to authorized users.

Effect of coffee and cocoa-based confectionery containing coffee on markers of cardiometabolic health: results from the pocket-4-life project

“…As previously reported [16], the sample size was calculated by considering as primary outcome the daily average concentration of a coffee-derived plasma circulating phenolic metabolite. In detail, 15 subjects had to complete an acute intervention to detect a change of 600 nmol/h/L −1 in dihydrocaffeic acid-3′-sulfate plasma concentration with a standard deviation (SD) of 870 nmol/h/L −1 (α error of 0.05, 80% power, and two-sided testing).…”

“…The study design has been previously published [16]. Briefly, in a three-arm, crossover, randomized trial, 21 volunteers were assigned to consume three treatments in a random order for 1 month: 1 cup of espresso coffee/day (hereinafter named "1C group"), 3 cups of espresso coffee/day ("3C group"), and 1 cup of espresso coffee plus 2 cocoa-based products containing coffee twice per day ("PC group").…”

“…This was the only dose of coffee for treatment 1C, whereas treatment 3C consumed two more cups of coffee (at 12.00 noon and 3.00 P.M.) (without sugar, sweeteners, and milk for the first coffee), while treatment PC consumed two cocoa-based products containing coffee twice during the day (at 12.00 noon and 3.00 P.M). Starting just after the consumption of the morning coffee, blood samples were collected at selected time points (t 0.5, t1, t2, t3, t4, t5, t6, t7, t8, and t9), as previously reported [16]. Five hours after the consumption of the morning coffee, participants received a standardized lunch (ham and cheese sandwich plus mineral water) free of coffee/cocoa-related phytochemicals.…”

Absorption, Pharmacokinetics, and Urinary Excretion of Pyridines After Consumption of Coffee and Cocoa‐Based Products Containing Coffee in a Repeated Dose, Crossover Human Intervention Study

“…Participants: The subject characteristics and the criteria for the recruitment have been already published. [25] Briefly, 21 volunteers, 10 males (2 smokers) and 11 females (6 smokers), aged 25.9 ± 0.5, weight 67.0 ± 2.7 kg, and BMI 22.3 ± 0.6 kg m −2 , were recruited in Parma (Italy). Those volunteers who agreed to participate were asked to sign the written informed consent to participate in the study.…”

“…Statistical Analyses: The sample size was calculated considering as primary outcome the daily mean concentration of a coffee derived plasma circulating phenolic metabolite, as previously reported. [25] Sample size was not calculated for secondary outcomes but 21 subjects can be considered appropriate also to observe significant differences in pyridine pharmacokinetic parameters, based on previously published data in which 13 volunteers (6 female and 7 male) were assessed. [24] Subgroup analysis by sex should be also powered (with 10 males and 11 females) attending to the data provided by Lang et al [24] Product pyridine content were expressed as mean ± standard deviation (SD).…”