Drinking hot tea can increase the risk of esophageal cancer. But note that this risk is not caused by the tea itself, but by the high temperature of the water.
Why?
Why is that? Let’s start with two related studies.
The first study:
In February 2018, the Annals of Internal Medicine published a study online by Dr. Canqing Yu of Peking University Health Sciences Center.
The study, which included more than 450,000 people followed for nine years, ultimately found that drinking hot tea (65°C) by itself did not increase the risk of esophageal cancer; it was drinking hot tea every day, drinking alcohol regularly, and smoking that increased the risk of esophageal cancer.
Specifically:
- Smoking and drinking are risk factors for esophageal cancer. And drinking hot tea can make it worse. “Hot tea + smoking” increased the risk of esophageal cancer by 56%, and “hot tea + drinking” increased the risk by 127%.
- If all three are present, the risk of esophageal cancer increases dramatically to 501%.
- The hotter the tea you drink, the higher the risk of esophageal cancer for people who both smoke and drink.
In his article, Dr. Yu points out that the incidence of esophageal cancer is rising globally, especially among men in underdeveloped countries. China has the highest incidence of esophageal cancer in the world, and Chinese men who love to drink tea tend to smoke and drink as well.
Why do smoking, alcohol, and tea increase the risk of esophageal cancer?
Drinking hot tea itself can lead to chronic damage to the esophageal mucosa, which can transform normal cells into cancer cells. But drinking hot tea is more of a “catalyst” that has a low risk of causing esophageal cancer alone, but can further increase the risk of other cancer-causing factors, such as smoking and drinking.
To explain further, drinking hot tea causes damage to the esophageal mucosa, and the body has to keep repairing the damage. In this case, the DNA is replicating and the cells are proliferating faster. The DNA will be replicated each time, but there is a possibility of error, which is a natural “weakness” of the body. This is a natural weakness of the body, and when combined with clear carcinogens such as alcohol and tobacco, it greatly increases the probability of DNA replication errors and the risk of mutations, which greatly increases the probability of esophageal cancer.
Dr. Yu pointed out that the International Agency for Research on Cancer has classified drinking beverages at temperatures above 65°C as “possibly carcinogenic to humans”; this, combined with alcohol consumption and smoking, makes the relationship between hot tea drinking and esophageal cancer quite complex.
A second study:
This study, published in the British Medical Journal (BMJ), was conducted by Farhad Islami et al from Tehran Medical University.
The researchers brought together 300 people with esophageal squamous cancer and 571 healthy people from similar lifestyle backgrounds and asked them questions about their tea drinking habits, including the temperature of the tea (divided into 4 levels: boiling hot, hot, warm, and slightly warm), and the brewing time.
The results showed that 98% of the participants drank black tea every day. Of these, 39% preferred tea below 60 degrees Celsius, 39% preferred tea between 60 and 64 degrees Celsius, and 22% preferred tea above 65 degrees Celsius.
People who drink “hot” tea are eight times more likely to develop esophageal cancer than those who drink warm or slightly warm tea, and those who drink “hot” tea are twice as likely to develop esophageal cancer.
Michael Thun, M.D., vice president emeritus of epidemiology for the American Cancer Society, commented that the paper is interesting in its interpretation of the relationship between hot tea and esophageal squamous carcinoma. He understands that in South America, especially Argentina, there is also a clear relationship between esophageal cancer and the consumption of boiling hot tea. The locals like to start enjoying the tea when it is boiling.
Summary
These two studies, one conducted in China and the other in Iran, which is also a developing country, has the same people of color, and also has a predominant type of squamous cancer, are very instructive for our lives.
There is no need to give up this hobby if you like tea, because tea itself is “sinless”. The company’s main goal is to provide a better solution to the problem. The first thing you need to do is to wait for the tea to cool down a little bit, especially in areas like Chaoshan, Guangdong, where you like to drink hot “work tea”.