The Link Between Temperature and Health
The primary concern highlighted by numerous studies revolves around temperature. The World Health Organization's International Agency for Research on Cancer (IARC) has classified drinking beverages hotter than 65°C (149°F) as a "probable carcinogen".
This conclusion isn't about the tea itself but rather the act of consuming any liquid at a scalding temperature. Studies conducted in regions where drinking very hot tea is common have found an increased risk of esophageal squamous cell carcinoma, a type of throat cancer. The consistent finding is that the risk increases with the temperature of the beverage.
How Hot Is 'Too Hot'?
So, what does 65°C feel like? For context, water boils at 100°C. Many tea enthusiasts brew black tea around 95°C and green tea around 80°C. A comfortable and safe drinking temperature is generally considered to be below 60°C. Most people would find a beverage at 65°C uncomfortably hot, bordering on scalding. The danger lies in habitually drinking tea at these very high temperatures, before it has had a chance to cool. A simple rule of thumb is to wait a few minutes after pouring. If you can’t hold the cup comfortably or have to take tiny, cautious sips, it is likely too hot.
The Damage of Thermal Injury
The mechanism behind the risk is straightforward: thermal injury. Repeatedly exposing the delicate lining of your esophagus to scalding liquids causes chronic inflammation and damage to the cells. Over a long period, your body's constant attempts to repair this damage can sometimes lead to cellular changes that may increase the risk of cancer. It’s important to understand that this risk is associated with a long-term habit, not the occasional cup of tea that was a bit too hot. Furthermore, the risk is significantly amplified for individuals who also smoke or regularly consume alcohol, which are major risk factors for esophageal cancer on their own.
Why an Empty Stomach Matters
While the cancer risk is primarily linked to temperature, the practice of drinking tea first thing on an empty stomach introduces other concerns. Tea contains compounds called tannins and caffeine. Without any food to act as a buffer, these substances can directly irritate the stomach lining. This can lead to an increase in stomach acid, causing discomforts like acidity, bloating, nausea, or a burning sensation. Over time, this can aggravate conditions like acid reflux or gastritis. While not directly linked to the cancer risk, it disrupts digestive wellness and can cause significant discomfort.
Nutrient Absorption and Hydration
Another consideration for the 'empty stomach' habit is nutrient absorption. The tannins in tea can bind with non-heme iron (the type found in plant-based foods), making it harder for your body to absorb this essential mineral. Having tea alongside or right before a meal can interfere with iron uptake. Starting your day with tea instead of water can also contribute to mild dehydration. Tea is a diuretic, meaning it makes you urinate more. After a night's sleep, your body is already in a state of dehydration, and leading with a diuretic can exacerbate that feeling.
Simple Steps for a Safer Sip
The good news is that making your tea habit safer is incredibly easy and doesn't require giving up your favourite beverage. First and foremost, practice patience. Let your freshly brewed tea sit for at least four to five minutes before you start drinking. This allows the temperature to drop to a safer, more enjoyable level below 60°C. Consider adding a splash of milk, which can help cool it down. To avoid digestive irritation, try not to make tea the very first thing you consume. Start your day with a glass of water to rehydrate. Having a small snack, like a few nuts or a biscuit, before or with your tea provides a buffer for your stomach lining. These small adjustments can make a world of difference to your long-term health.
