Can alcohol damage DNA?

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Researchers find a possible explanation why alcohol increases the risk of some cancers.

There is a link between high alcohol consumption and certain forms of cancer, but a good explanation for this is missing. There is a suspicious substance, namely acetaldehyde, a breakdown product of alcohol. Earlier it was shown that acetaldehyde disrupts the growth of cells in a lab scale. In this study, scientists from the British University of Cambridge conducted a series of experiments with mice.

The human body has an enzyme that neutralizes acetaldehyde: ALDH2. People who do not produce that enzyme (a lot, especially in East Asia) tolerate alcohol less well. In addition to ALDH2 there is a second protective mechanism, a protein called FANCD2, which can limit damage caused by acetaldehyde.

The researchers cultivated test mice that had been genetically manipulated: in some, the enzyme lacked ALDH2 and in others the protein FANCD2 was missing. All mice, also a control group, were given a diluted amount of alcohol. Mice without ALDH2 stopped the production of new blood cells, because the DNA of the stem cells for blood cells was damaged by the alcohol.

The same was true for the mice without FANCD2. Subsequently, the damaged stem cells of the test mice were transplanted into control mice, as a result of which the latter also produced fewer blood cells. The few blood cells that were made also showed DNA damage (mutations).

The researchers concluded that the enzyme ALDH2 plays an important role in the prevention of DNA damage in stem cells after administration of alcohol to mice, and that the absence of this enzyme may provide an explanation for the association of alcohol and cancer.

How should we interpret this news?

It is a study in experimental mice, the results of which you can not just extrapolate to people. However, it is not ethically possible to set up such a study in people. It is also not inconceivable that the ALDH2 mechanism is the missing link that explains why alcohol can cause certain cancers. In that case, especially people who do not make this enzyme are vulnerable to alcohol.

Deficiency of ALDH2 occurs frequently. Globally, an estimated 540 million people would produce little or no ALDH2. A symptom that indicates this is turning red after alcohol consumption. A 2009 study found a link between 'people who blush quickly when they have drunk alcohol' and esophageal cancer. Then there was no explanation for it. This relationship has been clarified with this new study.

Conclusion

Researchers find a possible explanation in animal research why alcohol increases the risk of some cancers. The explanation would have to do with the enzyme ALDH2, which eliminates harmful alcohol by-products that cause DNA damage. Whoever has a deficiency of ALDH2, would be more vulnerable to alcohol. A symptom of such a deficiency is flushing when you drink alcohol.