Clinical trial NCT01008020: Effects of Tea Catechin Consumption on the Prophylaxis of Influenza Infection
Official title: A Randomized Controlled Study on the Effects of Tea Catechin Consumption on the Prevention of Influenza Infection in Healthy Adults
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Influenza Infection
Keywords: tea catechin extracts
influenza infection
prophylaxis
supplements
adults over 20 years old
both men and women
Lead sponsor: University of Shizuoka
Sponsor class: OTHER
Collaborators: name: White Cross Nursing Home
First posted: 2009-11-05
Enrollment: 200
Sex: ALL
Minimum age (years): 20
Maximum age (years): 90
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: The Purpose of this study is to evaluate the effects of 5 months catechin consumption on the prevention of influenza infection.

Detailed description: Catechins are the major components of tea flavonoids and are reported to possess physiological activities such as antiviral effects. Recent experimental studies have revealed that tea catechin extracts prevent influenza infection, but few studies have been conducted on the clinical effects of tea catechin consumption on the prophylaxis of influenza infection. Based on these backgrounds, we designed a prospective randomized controlled study to evaluate the effects of 5 months tea catechin consumption on the prophylaxis of influenza infection.

Eligibility criteria: Inclusion Criteria:

* aged over 20 years
* possible to maintain without drinking tea more than 250 ml per day during the study
* possible to maintain without taking supplements or herbal products including catechin extracts during the study
* possible to fill out a questionnaire personally
* Obtained written informed consent before participation

Exclusion Criteria:

* Possessing some chronic infectious diseases in need of therapy
* Possessing tea or catechin allergy
* Possessing a history of influenza infection before six months prior to the study
* diagnosed as inadequate for other reasons to participate the study by principal investigator

Primary outcomes:
measure: the incidence rates of influenza infection
timeFrame: Until 5 months consumption of the study capsules
Secondary outcomes:
measure: the incidence rates of upper respiratory tract infections
timeFrame: Until 5 months consumption of the study capsules
measure: the severity of the symptoms and the duration of the cold among incident cases
timeFrame: Until 5 months consumption of the study capsules
measure: occurrence of the adverse events
timeFrame: Until 5 months consumption of the study capsules
Other outcomes:
Locations:
city: Higashi Murayama
country: Japan
facility: White Cross Nursing Home
state: Tokyo
Study officials:
affiliation: University of Shizuoka
name: Hiroshi Yamada, MD, PhD
role: STUDY_CHAIR
References:
citation: Matsumoto K, Yamada H, Takuma N, Niino H, Sagesaka YM. Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial. BMC Complement Altern Med. 2011 Feb 21;11:15. doi: 10.1186/1472-6882-11-15.