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.

Reference

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.

About two hundred health care workers in three different healthcare facilities in Japan were randomized to receive either a placebo or a combination of green tea catechins and theanine that contained 378 mg/day of catechins and 210 mg/day of theanine, both constituents found in green tea.

Of these eligible health care workers, 98 received the green tea and 99 received the placebo. The incidence of clinical signs and symptoms of influenza infection was significantly lower in the green tea (4.1%) group compared with the placebo group (13.1%).

Commentary:

The catechins and theanine in green tea have shown previous promise as a strategy for preventing influenza infections. In the laboratory, experiments have shown that green tea catechins can prevent influenza infection. A small study was then done that reported that gargling with tea catechins extracts was effective in preventing influenza infection in the elderly individuals in nursing homes. Green tea extracts have also been shown to enhance systemic immunity and prevent upper respiratory infections and influenza symptoms in adults. Based on this preliminary research, the more substantial randomized, double-blind study was done on the effectiveness of green tea catechins and theanine in preventing influenza infections. This is an extremely useful, simple, safe method of reducing the incidence of influenza. I will be advising my patients to take a standardized extract of green tea capsule regularly and/or drinking green tea liberally, especially during flu season.

Reference

Matsumoto K, Yamada H, Takuma N, et al. Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial. BMC Complementary and Alternative Medicine 2011; 11:15

This meta-analysis was done to assess the association between tea consumption and endometrial cancer. A total of 7 studies with 2 cohort studies and 5 case-control studies met the criteria for inclusion in this meta-analysis. Green teas and black teas were included in the search. A total of 3487 cases and of endometrial cancer and 104,643 non cases appeared in the pooled analysis. The results suggested that tea consumption was statistically significantly associated with reduced risk of endometrial cancer. The combine relative risk for ever drinkers vs. non/lowest drinkers was 0.85. Compared with non/lowest drinkers, the relative risk was 0.88 for low to moderate drinkers and 0.75 for high drinkers. An increase in tea intake of 2 cups per day was associated with a 25% decreased risk of endometrial cancer. In analysis by subgroup, green tea consumption was significantly associated with decreased risk whereas an association with black tea was not observed.

Commentary: The mechanisms whereby tea reduces the risk of endometrial cancer are multifactorial. Tea, even green tea, contains caffeine, which lowers free estrogen levels. A number of antioxidants are in green tea, and these “catechins” affect carcinogenesis in numerous ways including inducing apoptosis (cell death), inhibiting estrogen-induced activation of endometrial cells and scavenging free radicals. Tea also contains phytoestrogens and can have an estrogen antagonist effect on endometrial cells. Tea consumption also modifies genetic polymorphisms relevant in the development of endometrial cancer.

Reference

Tang N, Hua L, Qiu Y, Zhou G, Ma J. Tea consumption and risk of endometrial cancer : a metaanalysis. Am J Obstet Gynecol 2009;201:605.e1-8

Seven patients were excluded from analysis and the results were based on 495 patients (254 men and 241 women). Baseline warts were mainly on the vulva (41.2% of women), and penile shaft (36.9% men), followed by the perianal area (18.1% total), perineal area (15.3% total) and glans penis (11.8% men).

Complete clearance of all baseline and newly occurring warts occurred in 57.2% and 56.3% of patients treated with both 15% and 10% sinecatechins ointment compared with 33.7% for the vehicle (both P < .001). Significant results were observed at week 4 and 6 and all follow-up visits. Partial responses of at least 50% occurred in 78.4% of the 15% ointment group, 74.0% of the 10% ointment group, and 51.5% in the vehicle group. The recurrence on any wart occurred in 6.5% of the patients using the 15% ointment, 8.3% with the 10% ointment and 8.8% using the vehicle. There was also a very low rate of new warts at the end of the treatment in all groups.

Tatti S, Swinehart J, Thielert C, et al. Sinecatechins, a defined green tea extract, in the treatment of external anogenital warts. ObGyn 2008;111:1371-1379.

Commentary: External genital warts are one of the most common sexually transmitted infections, yet no single treatment has emerged as delivering the best outcomes. Options include herbal topical applications of thuja, licorice root and vitamin A, homeopathic medicines, and conventional treatments including podofilox solution or gels, imiquimod cream, trichloroacetic acid, cryotherapy, curettage, electrosurgery, excision, laser therapy, interferon and 5-fluorouracil gel.

This study is one of two independent phase III studies to establish efficacy and safety of sinecatechins ointment. Overall, patients in both the 15% and 10% ointment group had a significantly higher number of complete clearances of baseline warts and a lower number of recurrent lesions during the 12 week treatment free follow-up period. The results were better in women than in men, likely due to the greater keratinization of the skin on the penile shaft. Based on clearance rates of all warts, a 50% success was achieved in almost 80% of patients in both sinecatechins ointment strengths. Recurrence rates are higher in cryotherapy, imiquimod and podofilox. The results of the current study indicate that a green tea extract ointment standardized to 15% or 10% sinecatechins is a very effective topical treatment to clear warts, inhibit new external anogenital warts and keep patients wart free.