title: Acute effects of coffee consumption on self-reported gastrointestinal symptoms, blood pressure and stress indices in healthy individuals.
abstract: BACKGROUND
  It has been suggested that coffee may affect the gut-brain axis with conflicting outcomes. Moreover, there is insufficient evidence to determine whether the type or temperature of coffee consumed will have a different impact on the gut-brain axis. The purpose of this study was to investigate the effects of acute coffee consumption on the following: 1. self-reported GI symptoms and salivary gastrin, 2. stress indices [salivary cortisol and alpha-amylase (sAA)] and psychometric measures, and 3. blood pressure (BP), in healthy, daily coffee consuming individuals in non-stressful conditions.
  
  
  METHODS
  This was a randomized, double blind, crossover clinical trial, in which 40 healthy individuals (20 men, 20 women), 20-55 years of age, randomly consumed four 200 ml coffee beverages containing 160 mg caffeine (hot and cold instant coffee, cold espresso, hot filtered coffee), 1 week apart. Salivary samples and psychometric questionnaires were collected at baseline and post-coffee consumption at 15,30, and 60 min for salivary gastrin and sAA measurements and at 60,120, and 180 min for cortisol measurements. BP was measured at beginning and end of each intervention. ClinicalTrials.gov ID: NCT02253628 RESULTS: Coffee consumption significantly increased sAA activity (P = 0.041), with significant differences only between cold instant and filter coffee at 15 and 30 min post-consumption (P < 0.05). Coffee temporarily increased salivary gastrin, without differences between coffee types. Coffee did not affect salivary cortisol or self-reported anxiety levels. Coffee consumption significantly increased BP, within the healthy physiological levels, in a gender specific manner at the end of the experimental periods, without differences between coffee types.
  
  
  CONCLUSIONS
  Acute coffee consumption in non-stressful conditions activated sAA and BP but not salivary cortisol, indicating activation of the sympathetic nervous system. Post-coffee sAA increase without a concomitant cortisol increase may also indicate that coffee may have some anti-stress properties.
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, IeraOdos 75, Athens, 11855, Greece. emiliap@aua.gr.
authors.forename: Emilia
authors.identifier: http://orcid.org/0000-0002-4498-7105
authors.initials: E
authors.lastname: Papakonstantinou
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, IeraOdos 75, Athens, 11855, Greece.
authors.forename: Ioanna
authors.initials: I
authors.lastname: Kechribari
authors.affiliation: Department of Crop Science, Agricultural University of Athens, Athens, Greece.
authors.forename: Κyriaki
authors.initials: Κ
authors.lastname: Sotirakoglou
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, IeraOdos 75, Athens, 11855, Greece.
authors.forename: Petros
authors.initials: P
authors.lastname: Tarantilis
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, IeraOdos 75, Athens, 11855, Greece.
authors.forename: Theodora
authors.initials: T
authors.lastname: Gourdomichali
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, IeraOdos 75, Athens, 11855, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Michas
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, IeraOdos 75, Athens, 11855, Greece.
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Kravvariti
authors.affiliation: Second Department of Neurology, University of Athens Medical School, "Attikon" University Hospital, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Voumvourakis
authors.affiliation: Department of Food Science and Human Nutrition, Agricultural University of Athens, IeraOdos 75, Athens, 11855, Greece.|Department of Nutrition and Health, United Arab Emirates University, Al Ain, United Arab Emirates.
authors.forename: Antonis
authors.initials: A
authors.lastname: Zampelas
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000187:drug effects*; D002110:Caffeine / Q000008:administration & dosage; D003069:Coffee; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D005755:Gastrins / Q000032:analysis; D041981:Gastrointestinal Tract / Q000187:drug effects*; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011594:Psychometrics; D012463:Saliva / Q000737:chemistry; D057566:Self Report; D013312:Stress, Physiological / Q000187:drug effects*; D011795:Surveys and Questionnaires; D055815:Young Adult; D000516:alpha-Amylases / Q000032:analysis
chemical_list: D003069:Coffee; D005755:Gastrins; D002110:Caffeine; D000516:alpha-Amylases; D006854:Hydrocortisone
keywords: Blood pressure; Coffee; Salivaly cortisol; Salivary alpha-amylase; Stress