Alcohol converts to acetaldehyde and this can cause cancer

How can drinking alcohol cause cancer?

The type of alcohol present in alcoholic drinks is 'ethanol'. Ethanol itself is relatively non-toxic, however, it gets converted in the body to a highly toxic chemical called acetaldehyde. The reason why acetaldehyde is dangerous is because it can damage our DNA, and it is this genetic impact that can cause cancers. If acetaldehyde accumulates in cells, it reacts with DNA and can link two strands together, generating an extremely harmful form of damage known as a DNA interstrand crosslink or ICL.

Our bodies try to protect us from this process by preventing acetaldehyde building up, and produces three alcohol dehydrogenase (ALDH) enzymes, which rapidly break down acetaldehyde into acetate. This would normally mean that acetaldehyde doesn’t usually have time to build up for long enough. However, alcohol in the bloodstream can swamp this normal metabolic process.

Alcohol flushing mutation

Worse still, some people have a mutation causing ineffective ALDH enzymes, allowing acetaldehyde can build up. The so-called 'flushing mutation' is particularly common among Southeast Asian populations. 70% of the Taiwanese population have this mutation. As stated by Dr Ketan Patel, “People with mutated ALDH enzymes become flushed in the face and very often feel very sick after drinking alcohol.”

However, on a less "alarmist" note, Professor Byron Sharp, who specialises in marketing takes a different view commenting on the Cancer Research UK article says, "It is supported by the evidence that people with mutated ALDH enzymes (very rare for West Europeans) have substantially higher rates of these cancers even though they drink less. It must be noted though that these cancers are low (eg a tiny 0.3% of deaths are from oral cancers) in spite of most of the population drinking alcohol.

According to Cancer Research UK, there are basically three ways in which acetaldehyde can damage our DNA:

1. DNA ‘spelling mistakes’

Swapping nucleic acid 'bases' and therefore causing spelling mistakes in the code.

2. Messing with the chromosomes 

Acetaldehyde can cause bits of chromosomes to break off and to swap around, with genes ending up in the wrong place.

3. DNA 'adducts'

Acetaldehyde can to bind to DNA, forming clumps. These cause chaotic folding and replicates. Known as adducts, these are essentially another type of mutation.

The researchers point out that the best way to reduce the risk of cancer from alcohol is to drink less of it. They suggest having more alcohol-free days every week, swapping out some glasses of booze for soft drinks during a night out, or picking lower strength drinks or smaller servings.

Importance of gender

When it comes to understanding the relationship between alcohol, sobriety and gender, Dr Emily Nichols summarises saying, "using a gendered lens to look at drinking and sobriety can really help us to start to think about the ways in which alcohol is not a ‘neutral’ substance. Our experiences of drinking it – or indeed resisting it – are shaped by social processes and norms and by different aspects of our identities.

Whilst the ‘gendering’ of drinks endures, it is clear that public attitudes towards women’s drinking have changed. Whilst being very drunk might still be viewed as unattractive, risky or unladylike behaviour for women, generally women’s drinking is much more accepted and normalised, and we know that by 2016, women’s alcohol consumption was catching up with men’s in many countries. This is in part because the alcohol industry has identified women as a lucrative consumer market, resulting in products targeted specifically at women and the rise of phenomena such as ‘wine mom’ culture and the ‘feminisation’ of drinks such as ‘pink gin’ and rose wine. 

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