Blog này thảo luận và chia sẻ những tri thức về khoa học khí quyển và các khoa học khác.
"Mọi thứ chúng ta làm đều phải dựa vào nghiên cứu KHOA HỌC chất lượng cao nhất". Thien V. Le
Một nghiên cứu mới trên tám quốc gia cho thấy việc tiêu thụ nhiều thực phẩm siêu chế biến (UPF) có liên quan đáng kể đến tình trạng tử vong sớm gia tăng.
Summary: A new study across eight countries shows that higher consumption of ultraprocessed foods (UPFs) is significantly linked to increased premature deaths. Researchers found that each 10% rise in UPFs’ share of total energy intake raises all-cause mortality risk by 3%.
Countries with the highest UPF consumption, like the U.S., see up to 14% of premature deaths attributed to these foods. The findings highlight the urgent need for global policies promoting healthier, minimally processed diets to protect public health.
Nghiên cứu mới cho thấy chu vi vòng eo có khả năng dự báo nguy cơ ung thư liên quan đến béo phì ở nam giới mạnh hơn BMI, nhưng không hiệu quả ở phụ nữ.
Điều này có thể là do nam giới tích trữ nhiều mỡ nội tạng hơn, gây hại cho quá trình trao đổi chất và liên quan đến ung thư.
Các nhà nghiên cứu tại Nhật Bản, những người đang định lượng vấn đề này và phát triển các công cụ chẩn đoán mới, cho biết ngay cả việc uống một lượng nhỏ rượu cũng có thể làm tăng nguy cơ mắc một số bệnh ung thư.
Rượu là chất gây ung thư, đặc biệt là ở những người (thường là người châu Á) bị đỏ mặt ngay cả khi chỉ uống một lượng nhỏ.
If you were offered a drink and told that it contains a carcinogen, you might think twice about taking it. But the reality is that all alcoholic beverages fall into the category of ‘known carcinogens’ alongside tobacco, asbestos and radiation.
“There’s no such thing as a healthy amount of alcohol to drink,” says Manabu Muto, a professor in medical oncology at Kyoto University in Japan. “Drinking alcohol increases the risk of getting cancer of the head, neck and esophageal regions and so on.”
In 2020, 4.1% of cancers diagnosed globally and 741,300 cancer cases were attributed to alcohol consumption. Those are high numbers for a preventable form of cancer.
While the health risks of smoking tobacco are well known thanks to strong publicity, there is much less awareness of the risks associated with drinking alcohol.
“Anti-smoking awareness campaigns have a long history and have succeeded in increasing public awareness,” says Muto. “In contrast, moderate alcohol consumption has long been considered beneficial for health, which has led to less public interest in the health hazards associated with drinking alcohol.”
The World Health Organization (WHO) acknowledged this danger in 2022 when it published a statement in The Lancet Public Health stating that: “when it comes to alcohol consumption, there is no safe amount that does not affect health.”
In other words, the increased risk of developing certain cancers starts with the first drop. It’s true that the risk rises with increased consumption, but even at moderate levels they are low but not negligible.
Genetic risk
The greatest cancer-inducing substance might not be the alcohol itself, but rather a metabolic product of alcohol. The liver converts alcohol into acetaldehyde, which is a definite carcinogen. Acetaldehyde is generally broken down into acetate, which is then broken down into carbon dioxide and water.
However, roughly 8% of the world’s population carry a genetic mutation that reduces the activity of the ALDH2 enzyme1, which metabolizes acetaldehyde in the liver. This results (inactive ALDH2) in acetaldehyde lingering longer in the body, allowing it to do more harm to cells through causing double-stranded breaks in DNA, which can lead to mutations. Consequently, people with the mutation of ALDH2 gene are at much higher risk of developing alcohol-related cancers.
“People with inactive ALDH2 have low acetaldehyde metabolism and are at greater risk of developing cancer,” says Shinya Ohashi, an associate professor at Kyoto University Hospital and colleague of Muto.
In some Asian populations, the incidence of this mutation is much higher than the global average, being found in about 45% of people, who typically develop flushed faces after drinking even small quantities of alcoholic beverages.
Breath test
Since people metabolize alcohol at very different rates, it’s not enough to simply keep tabs on the amount of alcohol consumed. A much more accurate metric of the risk of developing alcohol-related cancers may be the amount of acetaldehyde in a person’s breath.
An illustration of a tumour on the wall of the esophagus. Alcohol consumption increases the risk of developing cancer of the esophagus.Credit: Kateryna Kon/Shutterstock
“We believe that measuring acetaldehyde is a more direct way of assessing risk,” says Muto.
With a view to incentivizing changing drinking habits, Muto’s team has developed a device that measures traces of acetaldehyde in exhaled breath2.
The device uses the adsorption properties of a small semiconductor gas sensor to measure electrical resistance, making it possible to easily measure even tiny quantities of acetaldehyde in a small device.
This test “enables people to gauge their alcohol metabolism — something that has been impossible until now,” says Muto. “Our hope is that providing an easy way to visualize the risk will help lead to behavioural change.”
Early detection
Another area that Muto’s team is working on is early detection of esophageal cancer, which is the sixth leading cause of cancer death globally. “Of all the cancers associated with consumption of alcoholic beverages, esophageal cancer is the most dangerous” says Akira Yokoyama, a medicine senior lecturer at Kyoto University, who is exploring the connection between alcohol and cancer along with Muto and Ohashi.
It is difficult to detect lesions in conventional endoscopic images (left). Narrowband imaging (NBI) of the same area reveals a lesion (right; brownish patch in the centre of image).Credit: Kyoto University
“About 80% of the world’s esophageal cancers occur in Asia, and the number of cases of esophageal cancer among Asians is predicted to increase by 63% by 2040 due to increasing rates of alcohol consumption and ageing populations.”
Early detection can be a life saver, he adds, as esophageal cancer is much more treatable in the early stages. This is borne out by the fact that Japan is an outlier in a plot of incidence of esophageal cancer against mortality based on WHO data — the mortality rate is much lower than expected based on incidence because of early detection.
“We’ve developed a narrow band imaging (NBI), a unique endoscopic technology, to aid the early detection of cancer of the esophagus and pharynx. This technique has now been used for the diagnosis of tumours occurring in the digestive tract, as well as in the esophagus and pharynx, and is used worldwide,” says Muto.
What drives cancer
The endoscopic technique is based on discoveries that Muto’s team have made into how cancer often takes hold in the esophagus and other regions. “We have elucidated the mechanism of field cancerization, in which multiple cancers frequently occur in the head and neck esophageal region,” says Muto.
First proposed in a 1953 study of oral cancer, field cancerization refers to the widespread carcinogenesis of cells across multiple regions of an organ or tissue in response to long-term environmental exposure to a carcinogen.
Endoscopic images obtained using iodine staining method of a heathy esophagus (left) and one showing signs of possible field cancerization (right).Credit: Kyoto University
Muto’s team discovered that alcohol consumption accelerated ageing in the esophagus and induced field carcinogenesis3,4. “Genomic analysis of the normal esophagus revealed that ageing increases the occurrence of cancer-driver mutations,” explains Yokoyama. “We found that alcohol consumption and smoking accelerate this change. Our work suggests that such mutations and DNA damage drive field cancerization.”
“Our endoscopic technique can detect field cancerization in the esophagus. People who show signs of field cancerization are at high risk of developing head and neck cancer and esophageal cancer. But it’s possible to suppress the proliferation of cancer by quitting smoking and drinking5,” explains Muto. “It’s important for more people to know about this.”
Toreduce risks, Muto advises people to minimize their consumption of alcohol. “Ultimately, drinking no alcohol is the safest level of alcohol consumption,” he says.
References
Aoyama, I. et al.Clin. Transl. Gastroenterol.8, e96 (2017).
