For many the script of these parties was identical: Christmas lunch, New Year’s toast and then straight to bed with the thermometer. With the boom of influenza which forced almost a million people to bed in the last week of December alone, the search for quick remedies has promptly returned to the priorities of Italians. And among the grandmother’s advice, that of “hot herbal tea to sweat and disinfect the throat” remains a great timeless classic. But dangerous.
Yes, because behind that steaming cup that seems to promise relief, lies a risk that science has now certified: drinking liquids at too high temperatures not only does not “kill viruses”, but can cause serious damage, to the point of increasing the risk of esophageal cancer.
The myth of the “hot” drink
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The idea that a drink must be “hot” to be effective is a myth. The belief that extreme heat can “disinfect” the throat is scientifically unfounded for a simple reason: the temperatures necessary to kill viruses and bacteria instantly would be incompatible with the life of our tissues.
In contrast, thermal shock caused by liquids above 60-65°C causes repeated microlesions to the mucosa of the esophagus. These invisible wounds, if repeated over time (as happens to those who often drink coffee, tea or other hot soups/drinks), create a chronic inflammatory state which forces them cells to continuously regenerate. And it is precisely in this process of forced repair that errors in cellular replication can occur, opening the door to tumor pathologies
Science’s verdict: “Probably carcinogenic”
The International Agency for Research on Cancer (IARC), which belongs to the WHO, has included drinks (in particular tea and mate) consumed at temperatures above 65°C in group 2A, that of substances “probably carcinogenic” to humans (here is an explanatory video). Warning: it is not the coffee or tea themselves that are under attack (indeed, if drunk at normal temperatures they fall into group 3, i.e. not classifiable as carcinogenic), but the heat is the risk factor. A study conducted on 50,000 people in Iran showed that those who regularly drank tea over the 60°C had a 90% chance more likely to develop esophageal cancer than those who drank it lukewarm.
The “5 minute rule”
If hot drinks are dangerous, what is the right temperature to enjoy a healing herbal tea without risk? Experts agree that the safety threshold is below 60°C. But since no one walks around the house with a kitchen thermometer in their pocket, here’s how to do it practically:
1 The sip test: if you can’t drink a whole sip without having to suck in air to cool it (“slooping”), it is too hot. Let it become lukewarm;
2 The rule of time: after pouring boiling water (100°C) onto the sachet, leave to infuse for the classic 3-5 minutes, then remove the sachet and wait another 4-5 minutes before drinking. This time allows the temperature to naturally drop below the risk threshold;
3 The milk trick: adding a drop of cold or room temperature milk instantly reduces the temperature by around 5-10 degrees, making the drink immediately safer.
Why warm is better (even for the flu)
Without prejudice to the fact that it is not the cold itself that makes us ill (indeed, exposing ourselves to low temperatures can do us good), drinking a herbal tea at 50-60°C is not only safer for the esophagus, but it is also more effective for the flu. At this temperature, the liquid is hot enough to aid vasodilation and loosen mucusbut does not irritate the mucous membranes already inflamed by the virus. A red throat is, in fact, a wounded throat: pouring boiling water on it is like throwing alcohol on a raw cut. It increases inflammation and pain, delaying healing. So, in these days of convalescence, feel free to prepare your honey and lemon herbal tea. But before you drink it, do your health a favor: put the cup down, wait five minutes and let it become a pleasure, not a burn.
