None listed
Conditions
Brief summary
Coffee is a staple drink around the world and is mainly consumed for its arousing effect. Available in different types, including espresso, boiled and instant, coffee is becoming increasingly popular in Hong Kong. The protective effects of habitual coffee consumption towards several chronic diseases related to unhealthy lifestyles, such as type 2 diabetes mellitus (T2DM), cardiovascular diseases (CVD) and metabolic syndrome, have been demonstrated. However these findings contradict with the results of acute feeding studies, which found that coffee is capable of impairing the body's own ability to control blood sugar level. This project aims at investigating the acute effect of consuming different kinds of coffee on the different biomarkers in blood. This project will be able to demonstrate the difference in effects upon consuming different types of coffee, which can lead to further investigation of the biological mechanisms involved. Long term consumption studies may also be carried out so that a comparison between the short-term and long-term effects is possible. Four types of coffee will be studied, including espresso, boiled, instant and decaffeinated coffee. After overnight fasting, each participant will consume a cup of test drink and consume a standard breakfast 60 minutes later. Blood samples will be taken to track the changes of the different metabolites during the session.
Interventions
The following test drinks are tested: espresso-, instant, boiled and decaffeinated coffee, both with and without sugar and milk added, as well as water and sugar-sweetened milk. The details of the test drinks are listed below:
Espresso-coffee: 35ml of the beverage is made from 7g of grounded coffee powder using an espresso machine (Delonghi 680). Caffeine content in one serve of espresso drink is 115mg.
Instant coffee: made by adding 2g of instant coffee powder into 140ml of near-boiling water
The following test drinks are tested: espresso-, instant, boiled and decaffeinated coffee, both with and without sugar and milk added, as well as water and sugar-sweetened milk. The details of the test drinks are listed below: Espresso-coffee: 35ml of the beverage is made from 7g of grounded coffee powder using an espresso machine (Delonghi 680). Caffeine content in one serve of espresso drink is 115mg. Instant coffee: made by adding 2g of instant coffee powder into 140ml of near-boiling water. Caffeine content in one serve of instant coffee drink is 110mg. Boiled coffee: made by adding 9g of grounded coffee powder into 175ml boiled water. Simmer for 10 minutes and cool in room temperature for 3 minutes. 150ml of the coffee beverage is served. Caffeine content in one serve of boiled coffee drink is 170mg. Decaffeinated coffee: made by adding 2g of decaffeinated coffee powder into 140ml of near-boiling water. Caffeine content in one serve of decaffeinated coffee drink is 3mg. All beverages listed above are tested in two versions: one with 50g low-fat cow's milk and 7.5 g white sugar added, while the other with nothing but black coffee. Control: 140ml of near-boiling water. Sweetened-milk: 50g of low-fat cow's milk and 7,5g of white sugar is added into 140ml of near-boiling water. The participant arrives in the morning with an empty stomach. He/she will give the first blood sample, then drink the test drink within 10 minutes. After 60 minutes, another blood sample will be taken. Then he/she will have to consume a standard breakfast made up of rice cereal, rice milk and glucose powder in 10 minutes. Investigators will make sure that the participant finishes the test drink and the standard breakfast. With a total of 10 test drinks and each of them being tested in two sessions, each participant will take part in a total of 20 sessions. A washout period of three days is given between each session.
Sponsors
The University of Hong Kong
Study design
Allocation
Randomised controlled trial
Primary purpose
Treatment
Eligibility
Sex/Gender
All
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
1. Aged between 18-40 years old 2. Body mass index (BMI) WITHIN the range of 18.0-23.0 3. Consume at least 2 cups of coffee on a weekly basis in the past 3 months 4. Have never smoked before 5. Not a vegetarian 6. Able to tolerate cow’s milk 7. Able to tolerate caffeine or coffee 8. Not on regular medication, except oral contraceptives 9. Women who are not pregnant or does not plan to be pregnant during the study 10. Without high blood lipid or cholesterol 11. Without diagnosed type 1 or type 2 diabetes 12. Without current or history of cardiovascular diseases 13. Without current or history of liver diseases 14. Without current or history of gastrointestinal diseases 15. Without haemophobia
Exclusion criteria
1. Aged out of 18-40 years old 2. Body mass index (BMI) not within the range of 18.0-23.0 3. Consume less than 2 cups of coffee on a weekly basis in the past 3 months 4. Ex- or current smoker 5. Vegetarian 6. Unable to tolerate cow’s milk 7. Unable to tolerate caffeine or coffee 8. On regular medication, except oral contraceptives 9. Women who are pregnant or plan to be pregnant during the study 10. With high blood lipid or cholesterol 11. Diagnosed with type 1 or type 2 diabetes 12. With current or history of cardiovascular diseases 13. With current or history of liver diseases 14. With current or history of gastrointestinal diseases 15. Haemophobia
Outcome results
None listed