Here is another study on the benefits of green tea and the incidence of influenza—this time in children. During the influenza season in Japan, a survey was conducted to detect the incidence of influenza infection and preventive measures that were being used including the flu vaccination status of children in a household, the frequency and quantity of green tea consumption, the frequency of preventive measures such as hand washing, facemasks and gargling, nutritional nourishment, sufficient sleep, thermal insulation, humidifying measures, ventilation and crowd avoidance excluding school attendance.
The incidence of type A influenza was significant and widespread in Japan through the study period of November 2008 to February 2009. A total of 2050 schoolchildren were included in the final analysis. The number of episodes of clinical influenza that were reported was 241, and 204 of those were confirmed by an antigen test. There were 185 cases of influenza A, 18 of influenza B and 1 case of combined.
More than 50% of the 2050 respondents drank green tea more than 6 days/week and 77.3% of the students drank < 1 cup a day and 1 to < 3 cups per day with approximately equal numbers of students in each group.
The consumption of 1-5 cups of green tea on an almost daily basis of 6 or more days/week was inversely associated with the incidence of influenza in this group of elementary schoolchildren. There was no evidence that more than 5 cups per day had any benefit for some reason.
Commentary: I am aware of six other studies on the prevention of influenza with green tea, including the previous blog posting in February, on my blog site. Collectively, these studies show that green tea inhibits the influenza virus in the laboratory, enhances systemic immunity in humans, and prevents the occurrence of cold and flu symptoms in adults. Drinking green tea and gargling with green tea are the methods that have been studied but for those of you who do not like or do not want to take the time to drink green tea, green tea capsules are another way to get the potential benefits of green tea.
Park M, Yamada H, Matsushita K, et al. Green tea consumption is inversely associated with the incidence of influenza infection among schoolchildren in a tea plantation area of Japan. J Nutrition 2011;141:1862-1870.