Groene thee verlaagt maagkanker bij vrouwen

Research Question:
Numerous in vitro and animal studies have shown that drinking green tea has a protective effect against cancer. However, the results of epidemiological studies are contradictory and therefore was carried out this review article.

Drinking green tea lowers the risk of getting stomach cancer?

Study Design:
This overview article contained 3 case-control studies, cohort studies 8.

Results and conclusions:
The researchers found no preventive effect of drinking green tea for stomach cancer.

But the hazard ratio found in 6 cohort studies in women who drank 5 or more cups of green tea a day, was 0.79 [95% CI = 0.65-0.96]. In other words, women who drank 5 or more cups of green tea a day, ran significant 21% less chance of getting stomach cancer than women who do not have green tea drunk.
Case-control studies also showed consistent a weak inverse association between drinking green tea and the risk of getting stomach cancer in women.

The researchers concluded that drinking 5 or more cups of green tea per day the risk of getting stomach cancer in women did decrease. However, the epidemiological evidence is still insufficient to be able to show any association in men.

Original title:
Green Tea Consumption and Gastric Cancer Risk: An Evaluation Based on a Systematic Review or an epidemiological Evidence Among the Japanese Population by Sasazuki S, Tamakoshi A, [...], Tsugane S.

Link:
http://jjco.oxfordjournals.org/content/42/4/335.short

Additional information about El Mondo:
The protective effect of green tea against stomach cancer in women is found in an overview article of cohort studies. But an overview article of cohort studies cannot prove a causal link between green tea and stomach cancer. An overview article of cohort studies can only answer the question: "should I adjust my diet?" give.
However it can not answer the question: "Is swallowing green tea supplements against stomach cancer make sense?" give. In order to answer this question, it should be found a protective effect in an overview article of Rcts. Only Rcts can demonstrate a causal link and when swallowing of food supplements should be a causal relationship are present.