Coffee and tea are associated with reducing the risk of brain tumors

"this is still in its infancy," said Dominique Michaud, who led the team at the University of Providence in Rhode Island and Royal College London. "this study should not be a reason for anyone to change their coffee and tea intake."

Even if coffee and tea have some direct effect on reducing the risk of glioma, the effect is small. Generally speaking, brain tumors are not common. For example, in Europe, the annual incidence is estimated to be 4/100000 to 6 in women and 6/100000 to 8 in men.

Overall, a person's chance of developing a malignant brain tumor (cancer) in his or her lifetime is less than 1%.

If high coffee and tea intake protects against gliomas to some extent, researchers will be able to explore the causes of brain tumors at a deeper level, Mishod said. "right now, we know very little about the causes of brain cancer," she said in an interview.

The findings, published in the American Journal of Clinical Nutrition, are based on ongoing surveys of potential risk factors for cancer in ten European countries. At the beginning of the survey, 521488 respondents between the ages of 25 and 70 filled out questionnaires about their medical history, diet, exercise habits, smoking and other lifestyle factors.

Mishod's team followed more than 410000 participants who were cancer-free at the time of the survey and had complete dietary information. After an average of 8.5 years of follow-up, 343 were diagnosed with gliomas and 245 with another benign brain tumor called meningioma.

When the researchers divided the participants into four to five groups according to their coffee and tea intake at the time of the survey, they did not find a "positive correlation with intake", that is, increased coffee and tea intake and a lower risk of developing gliomas.

But when the researchers looked at the two groups, they found a difference: people who drank at least 3.5 ounces of coffee or tea a day, and people who drank less than 3.5 ounces a day or none at all.

People who drank more coffee / tea had a 1/3 lower risk of being diagnosed with gliomas, taking into account factors such as age and smoking history. However, there was no direct association with the risk of meningioma.

According to Mishod, they don't know why coffee and tea intake is not positively correlated with reduced glioma risk, which is often seen as an important sign of possible cause and effect. But this may have something to do with the difficulty of accurately measuring coffee and tea intake of participants, as the survey is based entirely on data reported by the participants themselves.

However, the findings that coffee / tea may affect the risk of glioma are still important from a biological point of view, Mishod said.

For example, a recent laboratory study found that caffeine slows the growth of glioblastoma. In addition, coffee and tea contain antioxidants that protect human cells from damage, thereby preventing cancer and other diseases.