The Acute Effect of Coffee Consumption on Stomach, Self-reported Gastrointestinal Symptoms and Stress.

Agricultural University of Athens40 enrolled

Overview

This study investigated the acute effect of the consumption of four different kinds of coffee (hot and cold instant coffee, cold espresso and hot filter coffee) with the same caffeine content on salivary gastrin, cortisol and alpha-amylase concentrations, on self-reported gastrointestinal symptoms and on psychometric assessments in healthy individuals.

Coffee consumption is very common in Greece. Many of the consumers support that certain types of coffee and especially instant coffee cause gastrointestinal symptoms in healthy individuals. Up to now, few studies have investigated the relationship between coffee consumption, gastrointestinal symptoms and stress in healthy individuals with conflicting results.Coffee consumption is related with increased gastric acid and gastrin secretion, however it does not seem to affect stomach or stomach walls. Stress, which characterizes modern lifestyle, also is found to increase gastric acid and gastrin secretion and seems to be exclusively responsible for gastrointestinal symptoms.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Masking

SINGLE

Enrollment

Conditions

Stress Signs and Symptoms, Digestive Blood Pressure Increased Secretion of Gastrin

Interventions

Cold espressoOTHER

Volunteers consumed cold espresso with 160 mg caffeine. Salivary gastrin, alpha-amylase and cortisol and self-reported GI symptoms and stress were collected at fasting and postprandially.

Hot instant coffeeOTHER

Volunteers consumed hot instant coffee with 160 mg caffeine. Salivary gastrin, alpha-amylase and cortisol and self-reported GI symptoms and stress were collected at fasting and postprandially.

Cold instant coffeeOTHER

Volunteers consumed cold instant coffee with 160 mg caffeine. Salivary gastrin, alpha-amylase and cortisol and self-reported GI symptoms and stress were collected at fasting and postprandially.

Eligibility

Sex: ALLMin age: 20 YearsMax age: 55 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Stable body weight for at least 1 month prior to study enrollment. Exclusion Criteria: * If one volunteer consumed breakfast more than three days a week, their daily caffeine intake was over 500 mg caffeine, was taking medication, their psychological state was strongly influenced by some exogenous factor (e.g. moving to a new house, new job, divorce e.t.c.), was on hypocaloric diet for weight loss, was smoking more than five cigarettes a day, was an athlete with very vigorous physical activity (\> 4 hours vigorous exercise a day), had a history of gastrointestinal disorders (e.g. gastroesophageal reflux disease (GERD), irritable bowel syndrome, diarrhea, ulcers e.t.c.), depression, diabetes, kidney disease, hypertension, blood disorders, liver disease, unregulated hyper - or hypothyroidism, arrhythmia, heart disease, cancer, vascular disease, recent surgery, or severe psychiatric disorders was automatically excluded from the study.

Outcomes

Primary Outcomes

Salivary gastrin and self-reported gastrointestinal symptoms

The volunteers visited the lab after an 8-hour fasting. Saliva samples were taken at fasting for the determination of fasting salivary gastrin. After the consumption of coffee, saliva samples were taken at 15, 30, 60' for the determination of gastrin. Saliva samples were collected by the method "Salivette". Saliva was carried out by chewing a swab for about 1 minute. Then, the swab was returned to the Salivette and the container was centrifuged and saliva sample was obtained. The samples were stored at - 20 degrees of Celsius. Gastrin was determined by an immunoenzymatic method. In order to record the effects of coffee consumption on gastrointestinal symptoms, the participants completed a visual analogue scale every time saliva samples were collected (time 0', 15', 30', 60', 120', 180'). The visual analogue scale (1 = not at all to 10 = very) included 12 questions about gastrointestinal symptoms.

Time frame: 4 weeks

Secondary Outcomes

Blood pressure, energy intake and physical activity

The aim was to investigate if blood pressure, energy intake and physical activity changed during the intervention. Blood pressure was measured three times in a sitting position after 15 minutes of rest by a mercury sphygmomanometer at the beginning and ending of each trial respectively. There was a 2-minute interval between measurements. Then, the average blood pressure measurements were calculated. Dietary intake was analyzed by Diet Analysis Plus (version 6.1). The database was extensively modified to include new foods and recipes. Physical activity was estimated by using metabolic equivalents of different activities performed by the volunteers the previous 7 days. Then, mean daily energy expenditure was estimated.

Time frame: 4 weeks

Salivary cortisol and alpha-amylase

The volunteers visited the lab after an 8-hour fasting. Saliva samples were taken at fasting for the determination of fasting salivary cortisol and alpha-amylase. After the consumption of coffee, saliva samples were taken at 15, 30, 60' for the determination of alpha-amylase and at 60, 120, 180' for cortisol determination.Saliva samples were collected by the method "Salivette". Saliva was carried out by chewing a swab for about 1 minute. Then, the swab was returned to the Salivette and the container was centrifuged and saliva sample was obtained. The samples were stored at - 20 degrees of Celsius. Cortisol was determined by an immunoenzymatic method. Alpha-amylase was determined by a kinetic enzyme assay kit.

Data from ClinicalTrials.gov

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