Drinking hot tea can increase the risk of esophageal cancer, especially if you are a heavy drinker or smoker, a new study has found.
But even those who don’t touch alcohol or cigarettes appear to have a higher risk, researchers warned, but they stressed more tests are needed to assess how damaging it could be.
The new study done by scientists in China found drinking tea heated to over 65C (149F) was associated with a five-fold increased risk for esophageal cancer when combined with excessive drinking or heavy smoking.
The Chinese scientists the link was ‘biologically plausible’ as thermal injury caused by the hot tea to the gullet lining impairing its ability to act as a barrier to harmful toxins from alcohol and smoking.
Experts said while the results may sound alarming, there was no need to stop having a daily brew as most people drank tea or coffee below 65C or 149F, temperature which ‘seems unlikely to cause cancer.’
The cancer affects the gullet, the food pipe from the throat to the stomach, mainly in people in their 60s and 70s with men more at risk than women.
In the early stages it does not usually cause any symptoms when the tumour is small but when it grows symptoms begin to show.
These can include difficulties in swallowing, persistent indigestion or heartburn, bringing up food soon after eating, a loss of appetite and weight loss, or pain in the upper tummy, chest or back.
Persistent heartburn, smoking, drinking too much over a long time, being overweight or obese and having an unhealthy diet that’s low in fruit and vegetables are known risk factors.
Lead author Dr Jun Lv at the Peking University Health Science Center explained: ‘Tea, one of the most common beverages worldwide, usually is consumed at elevated temperatures.
‘Existing evidence remains inconclusive regarding whether hot tea drinking is associated with oesophageal cancer risk.
‘Although several studies have demonstrated inhibitory effects of tea against tumourigenesis in the digestive tract, chronic thermal injury to the oesophageal mucosa may initiate carcinogenesis.
‘The International Agency for Research on Cancer recently classified the intake of scalding beverages above 65C as ‘probably carcinogenic to humans.’
So the study set out to examine whether high-temperature tea drinking, along with the established risk factors of alcohol consumption and smoking, was associated with oesophageal cancer risk.
The findings was based 456,155 Chinese men and women aged 30 to 79 who were followed for a median of 9.2 years.
China is among the countries with the highest oesophageal cancer incidence and tea drinkers, especially Chinese men, are more likely to also smoke and drink alcohol.
Tobacco smoking and alcohol consumption, as well as the chemical compounds and adverse thermal effect of hot tea, considerably complicate the association between tea drinking and cancer risk.
It found 1,731 cases of oesophageal cancer.
High-temperature tea drinking combined with either alcohol consumption or smoking was associated with a greater risk for esophageal cancer than hot tea drinking alone.
Compared with participants who drank tea less than weekly and consumed fewer than 15g of alcohol daily, those who drank burning-hot tea and 15g or more of alcohol daily had the greatest risk for esophageal cancer – a hazard ratio of five.
Likewise, the hazard ratio for current smokers who drank burning-hot tea daily was 2.03.
The study found a synergistic association between hot tea drinking with excessive alcohol consumption or smoking and the risk for oesophageal cancer.
Participants who drank high-temperature tea, consumed alcohol excessively, and smoked had an oesophageal cancer risk more than five times greater than those who had none of those three habits.
However, the absence of both excessive alcohol consumption and smoking, daily tea drinking was not associated with oesophageal cancer risk.
Dr Lv said: ‘The present study found evidence of increased oesophageal cancer risk with higher tea temperatures.
‘Additional studies are needed to confirm our findings.’
Dr Lv concluded the findings suggest that abstaining from hot tea may be beneficial for persons who drink alcohol excessively or smoke.
The study was published in the journal Annals of Internal Medicine.
In an editorial Dr Farin Kamangar of the Morgan State University and Dr Neal Freedman of the National Cancer Institute, both in Maryland. said the idea that hot drinks may cause the cancer dates to the 1930s.
He said: ‘Tea drinkers may be concerned about the implications of this study on their risk for cancer.
‘Of importance, however, is that the accumulated literature suggests little risk from hot drinks at temperatures below 65C (149F).
‘Most people drink beverages at temperatures lower than that threshold; for example, in the United States, coffee typically is consumed at around 60C (140F)
‘For these and other reasons, these findings should be interpreted cautiously.’
They noted the results were based on observations and tea and coffee have been shown to have healthy compounds.
They concluded: ‘Perhaps those of us who drink hot beverages often should be prudent and wait for the liquid to cool a bit first.
‘However, the results of this study should not cause people to abandon their favourite beverage.
‘Most people drink their tea and coffee at a temperature that seems unlikely to cause cancer.’
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