Avoid "eating while hot" to protect your health

In winter, eating a hot meal makes the whole person extremely comfortable
.
Chinese traditional diet is "eat hot": at the dinner table, the host will invite guests to eat it hot, and parents will tell their children to eat
it hot.
A cup of hot tea and a bowl of hot soup are Chinese most familiar "food guides"
.
However, there is a red line of "eating while hot", and if you cross it, you may develop esophageal cancer
.

Often eat hot food and have a high risk of cancer

According to the report released by the National Cancer Center, esophageal cancer in China is the sixth high-incidence cancer, the top five are lung cancer, colorectal cancer, stomach cancer, liver cancer, and breast cancer
.
The annual number of new cases of cancer in China is 4.
064 million, of which the annual number of esophageal cancer cases is 253,000
.
Data show that China accounts for more than half of the world's new cases of esophageal cancer every year, and the situation is not optimistic
.

Esophageal cancer mainly includes adenocarcinoma and squamous cell carcinoma, more than 90% of esophageal cancer cases in China are squamous cell carcinoma, and most of the patients have progressed to the middle and advanced stages when diagnosed, and the overall 5-year survival rate is less than 20%.

So, why is esophageal cancer more common in China?

According to the investigation of all cancer causes by Chinese and foreign researchers, tobacco and alcohol are two important triggers, but this is only a general commonality, and there are specific causes
for different cancers.
As far as esophageal cancer is concerned, there are two specific triggers: one is eating preserved foods; The second is to eat hot food
.

Lin County in the Taihang Mountains region of Henan Province, China, was a high incidence area
for esophageal cancer in the 70s of the 20th century.
To solve this mystery, the Chinese Academy of Medical Sciences and local researchers investigated the diet and eating patterns of the people of Linxian County and found the crux of the
problem.

First of all, local residents love to eat pickled and fermented vegetables, the juice surface of pickles is often covered with a thick layer of white mold, and residents will drink
these fermented juices as drinks in summer.
At the same time, many residents take water from dry wells and ponds and store it in tanks for drinking, mostly from rainwater, mixed with household waste and agricultural fertilizers, and the water contains high concentrations of the carcinogen nitrite
.
Studies have shown that people who prefer to eat preserved foods have a 9.
44 times
higher risk of esophageal cancer than the general population.

Secondly, local residents love hot food, and can even easily swallow hot food
at 80°C-88°C.
Studies have pointed out that food is too hot and hot is one of the reasons for the high incidence of esophageal cancer in Linxian County, and the risk of esophageal cancer in people who like to eat piping hot food is 7.
6 times
that of the general population.

In order to reduce the occurrence of esophageal cancer, Lin County advocated lifestyle changes, local residents gradually reduced the consumption of pickled foods and hot foods, and the incidence of esophageal cancer began to decline
.
Linxian has adopted five anti-cancer measures of "mold prevention, amine removal, treatment of hyperplasia, application of molybdenum fertilizer, and change of bad living habits", of which bad living habits include eating pickled food and eating hot food
.
By 2020, the incidence and mortality of esophageal cancer in Linzhou had decreased by 50%.

Eating temperatures below 54°C is safer

China has the habit of eating while hot, such as eating hot dumplings in the north and hot pot in the south, which is undoubtedly an important cause of the high incidence of esophageal cancer in Chinese, and there is also sufficient evidence to prove
it.

In June 2016, a study published in The Lancet Oncology by the International Center for Research on Cancer of the World Health Organization pointed out that drinking hot drinks above 65°C increases the risk of esophageal cancer, and in the official published carcinogen evaluation report, very hot (above 65°C) drinks are listed as very likely (class IIA) carcinogens (meaning limited evidence of carcinogenicity to humans and sufficient evidence of carcinogenicity to laboratory animals).
This type of carcinogen is second only to the highest level of grade 1 carcinogens (meaning that there is a clear risk of carcinogens).

Therefore, limiting the consumption of foods with high temperatures above 65 ° C should be the red line
for preventing esophageal cancer.

However, this high temperature red line has now been pulled down to 54°C by a new Chinese study, which explains the molecular mechanism of why hot food can induce esophageal cancer
.

A high-temperature diet subjects the esophageal mucosa to frequent, repeated heat stimulation, resulting in damage to esophageal mucosal epithelial cells, thereby increasing the risk of lesions, but the molecular mechanisms are not well understood
。 This time, researchers from the Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, published an article in the British Cancer Journal that hot food can repeatedly act on the transient receptor potential ion channel vanillin isoform 2 (TRPV2) of cells, activating a variety of cell signaling pathways, and these signaling channels can significantly promote the malignant behavior of esophageal squamous cell carcinoma cells in vitro tests, and can significantly promote the tumorigenesis and spread
of esophageal squamous cell carcinoma in vivo.
This indicates that heat-sensitive TRPV2 channels play an important role
in the development of esophageal squamous cell carcinoma.

After gradually adjusting the temperature, the researchers found that 54°C can activate the TRPV2 channel, and after the short and frequent stimulation of esophageal squamous cell carcinoma cells with this heat, the obvious proliferation, invasion and promotion of malignant cell behaviors
such as esophageal squamous cell carcinoma cells can be observed in vitro experiments.
Subsequently, the researchers used TRPV2-specific activators to act on esophageal squamous cell carcinoma cells and obtained similar results
.

Finally, this study summarized the molecular mechanism of hot food-induced cancer as follows: TRPV2 can upregulate the heat shock factor 1 of cells and promote the transcriptional expression of heat shock proteins 70 and 27 in esophageal squamous cell cancer cells after being activated by heat stress, thereby promoting the tumorigenicity and aggressiveness
of esophageal squamous cell carcinoma.

In simple terms, TRPV2 is distributed in organs and tissues such as nerves, blood vessels, and spleen, and is involved in regulating a variety of important physiological functions, such as nociception, neurodevelopment, and immune response
.
It is also one of its functions to respond to heat and stimulate various nerve channels to increase the tumorigenius and aggressiveness of
esophageal squamous cell carcinoma.

Leave it to dry for a while and then eat it without being anxious

Hot blanching food can trigger the cell's hot channel, which has been demonstrated in other studies before
.
The 2021 Nobel Prize in Physiology or Medicine recognizes discoveries
into sensations such as touch, pain, and heat.
The heat and pain people feel when eating chili peppers is similar to the pain they feel when burned by heat because the TRPV1 channel
is triggered.
This channel can be activated by capsaicin or high temperatures above 43°C, producing electrical signals, which travel along the nervous system to the brain, which is interpreted by the brain as pain
.
In the same way, the channel activated by cold is TRPM8, the mustard receptor (channel) is TRPA1, and the taste channel of spices such as thyme is TRPA3
.
Then, since researchers have revealed the mechanism by which hot food induces esophageal cancer, the public should be vigilant and try not to eat or eat less hot food, such as piping hot porridge soup, tea, etc
.

Chinese love tea, and a good cup of tea is a grand hospitality
.
Freshly boiled water to brew tea, tea aroma is strong, but the tea temperature at this time is at least 80 ° C - 90 ° C, even if the heat dissipation is blown before drinking, there is still 70 ° C - 80 ° C
.
Of course, it does not mean that you can't use boiling water to make tea, nor do you let everyone drink herbal tea, but you should pay attention to the time
of drinking tea.
If you make tea with boiling water, let it dry for at least 5-10 minutes before sipping
.
In the same way, don't worry when eating hot pot, at least take the hot meat and vegetables to the plate and let it dry for a while before eating
.

Compared with the standard recommended by the International Agency for Research on Cancer to drink hot drinks not exceeding 65 ° C, the temperature of most foods does not exceed the standard, even if it is food that needs to be cooked at high temperatures, as long as it is not eaten often, it will not cause serious consequences, because only the dose and frequency can determine whether a substance or a way is toxic or harmful
to the human body.

The advice "eat while hot" is often hung on the dinner table, in fact, there is another meaning: "don't be hot"
.
High-temperature food has been shown to be associated with the occurrence of esophageal cancer, although it is not an absolute causal relationship, but as one of the known carcinogenic risks, it is still recommended that people prevent the disease before it occurs, avoid long-term intake of high-temperature food in the daily diet, and do a good job in the prevention
of esophageal cancer.

(Zhang Tiankan)

China Food News(Version 06, December 01, 2022)

(Responsible editor: Zhu Meiqiao)