Effects of Tea Catechin Consumption on the Prophylaxis of Influenza Infection

A Randomized Controlled Study on the Effects of Tea Catechin Consumption on the Prevention of Influenza Infection in Healthy Adults

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

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.

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