[Weekly Health] Is ‘excessive drinking’ the only risk of cancer?… Ministry of Health and Welfare excuses warning label on alcohol bottles

Starting on the 9th, health warnings displayed on alcohol bottles and cans were further strengthened. The font size of the warning message has been increased, and a new warning picture has been introduced to indicate the dangers of drunk driving.

The purpose is to make consumers more clearly aware of the fact that drinking can have a serious impact not only on personal health but also on social safety.

However, from the perspective of cancer prevention, there are important loopholes in this reform.

This is because, although it is known that alcohol can cause cancer, it still uses expressions that seem to limit the risk to 'excessive drinking'.

One of the health warnings newly presented by the Ministry of Health and Welfare is “Alcohol is a carcinogen, and excessive drinking causes liver cancer and stomach cancer.”

Although this may sound obvious at first glance, consumers who read this statement may accept that they do not have to worry about the risk of developing cancer as long as they avoid excessive drinking. This means that it can be a kind of ‘indulgence’ that it is okay to drink alcohol in small amounts.

This is why the Korean Cancer Prevention Society, the leading cancer prevention expert group, recently issued a statement calling for improvements in the mainstream health warning label system.

The society positively evaluated the government's strengthening of warning signs to raise awareness of the health risks of drinking, but pointed out that the scientific evidence regarding the carcinogenic risk of alcohol was not sufficiently reflected.

In fact, the International Agency for Research on Cancer (IARC) under the World Health Organization (WHO) classifies alcoholic beverages as a ‘group 1 carcinogen’ with confirmed human carcinogenicity.

Group 1 carcinogens mean that there is sufficient scientific evidence to suggest that they cause cancer in humans. Tobacco and asbestos also fall into the same category. However, just because they are in the same group 1 does not mean that the level of cancer risk is the same.

Cancers for which a causal relationship with alcohol consumption has been established include oral cancer, pharyngeal cancer, laryngeal cancer, esophageal cancer, liver cancer, colon and rectal cancer, and female breast cancer.

The risk of developing cancer tends to increase as the amount of alcohol consumed increases, but the problem is that even small amounts of alcohol can increase the risk of developing some cancers. In particular, female breast cancer is a representative cancer in which an increased risk is observed even with relatively small amounts of alcohol.

This fact is also confirmed in international cancer incidence statistics.

According to a study led by IARC researchers and published in the international academic journal 'Lancet Oncology' in 2021, it was estimated that about 741,300 (4.1%) of new cancers that occurred around the world in 2020 were caused by alcohol consumption.

What is noteworthy is that about 103,100 of these cases (13.9%) were analyzed to be due to drinking less than 20g of pure alcohol per day. 20g of pure alcohol is equivalent to approximately 160mL of soju with an alcohol content of 16% and approximately 500mL of beer with an alcohol content of 5%. This means that about 1 in 7 cases of alcohol-related cancer worldwide are related to relatively small amounts of alcohol.

So why does drinking even a little alcohol increase the risk of developing cancer?

The key lies in the process by which alcohol is broken down in the body.

Ethanol in alcohol is converted into a substance called acetaldehyde in the body. This substance can damage the genes (DNA) of cells and cause mutations, thereby contributing to the development of cancer. Oxidative stress, chronic inflammation, and changes in hormonal metabolism caused by alcohol consumption are also known to affect the carcinogenesis process.

In addition, East Asians, including Koreans, have genetic characteristics that should be noted. It is relatively common for people to be genetically deficient in the activity of the enzyme (ALDH2) that decomposes acetaldehyde.

When these people drink alcohol, more acetaldehyde may accumulate in their bodies, and the risk of developing esophageal cancer and head and neck cancer may increase.

The so-called 'Asian flush' phenomenon, in which the face turns red easily when drinking alcohol, is a representative clue that suggests this genetic trait.

Therefore, the phenomenon of facial flushing when drinking alcohol should not be taken lightly as simply a weak constitution.

Drinking habits at a young age are also important.

A large-scale prospective cohort study cited by the society found that the more alcohol a woman consumes from menarche until her first full-term pregnancy, the higher the risk of developing breast cancer later.

This suggests that drinking habits during adolescence and young adulthood may be linked to long-term cancer risk beyond immediate health problems.

Based on this scientific evidence, the WHO Regional Office for Europe and IARC recommended in a joint statement in 2023 that when explaining the carcinogenic risk of alcohol, expressions that limit the risk to a specific drinking level, such as 'harmful drinking' or 'excessive drinking', should not be used.

This is because research to date has not identified a clear baseline level of drinking at which the risk of cancer begins to increase.

Korea has already strengthened its national cancer prevention guidelines in 2016 from 'drink no more than two glasses of alcohol a day' to 'avoid drinking even one or two small drinks a day to prevent cancer.'

The national cancer prevention guidelines recommend avoiding even small amounts of alcohol, but the health warnings on alcohol bottles actually emphasize 'excessive drinking.'

There are also limitations in the warning display method.

Under the current system, one of several warning statements regarding health risks can be selected to be displayed. If an alcoholic beverage manufacturer chooses a warning about stroke or memory impairment instead of a statement containing the expression ‘carcinogen,’ consumers may not receive information about the risk of cancer from the product.

In addition, warning pictures were prepared to communicate the dangers of drunk driving and drinking during pregnancy, but no separate warning pictures were presented to visually convey the carcinogenic risks of alcohol.

Accordingly, the Korean Society for Cancer Prevention urged that the modifier 'excessive' be removed from the warning and that the carcinogenic risk of alcohol itself be clearly communicated, such as 'Drinking increases the risk of developing cancer.'

In addition, it was emphasized that cancer risk warning signs and warning pictures should be mandatory on all alcoholic beverages, relevant laws should be revised, and cancer prevention education should be strengthened starting from adolescence.

Na Hye-kyung, president of the Korean Society for Cancer Prevention, said, "The small warning sign on alcohol bottles is one of the most direct health messages the government sends to the public. If that message leaves a misunderstanding that 'it's okay as long as you don't drink too much,' the effect of the warning is bound to be halved."