Prevention of Acute Upper Respiratory Infections by Consumption of Catechins in Healthcare Workers: A Randomized, Placebo-Controlled Trial.

Catechins, phytochemicals contained mainly in green tea, exhibit antiviral activity against various acute infectious diseases experimentally. Clinical evidence supporting these effects, however, is not conclusive. We performed a placebo-controlled, single-blind, randomized control trial to evaluate the clinical effectiveness of consumption of catechins-containing beverage for preventing acute upper respiratory tract infections (URTIs).

Effects of green tea consumption on cognitive dysfunction in an elderly population: a randomized placebo-controlled study.

Background: Green tea is a beverage with potential effects on cognitive dysfunction, as indicated by results of experimental studies. However, its effects in humans, especially at real-world (typical) consumption levels, are unclear.

Methods: A double-blind, randomized controlled study was conducted to assess the effects of green tea consumption on cognitive dysfunction (Mini-Mental State Examination Japanese version (MMSE-J) score <28) in Japan.

Green tea consumption affects cognitive dysfunction in the elderly: a pilot study.

Green tea is known to have various health benefits for humans. However, the effect of green tea consumption on cognitive dysfunction remains to be clinically verified. We conducted a clinical study to investigate the effects of green tea consumption on cognitive dysfunction.

Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial.

Background: Experimental studies have revealed that green tea catechins and theanine prevent influenza infection, while the clinical evidence has been inconclusive. This study was conducted to determine whether taking green tea catechins and theanine can clinically prevent influenza infection.

Design, Setting, And Participants: A randomized, double-blind, placebo-controlled trial of 200 healthcare workers conducted for 5 months from November 9, 2009 to April 8, 2010 in three healthcare facilities for the elderly in Higashimurayama, Japan.

Gargling with tea catechin extracts for the prevention of influenza infection in elderly nursing home residents: a prospective clinical study.

Objectives: To evaluate the effects of gargling tea catechin extracts on the prevention of influenza infection in elderly nursing home residents.

Design: A prospective study conducted for 3 months from January to March 2005.

Settings/location: A nursing home in Japan.