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Can alcohol mouthwash increase cancer risk?

Can alcohol mouthwash increase cancer risk?

The latest cancer scare story to hit the headlines this week was about mouthwash.  An Australian researcher claimed to have found ‘sufficient evidence’ of a link between alcohol in mouthwashes and mouth cancer.

He even went on to suggest that ‘it is inadvisable for oral healthcare professionals to recommend the long-term use of alcohol-containing mouthwashes’.

Now, most people reading the story may feel the need to run home and clear their bathroom shelves. But hold on, don’t pour your bottle of mouthwash down the sink just yet. Let’s take a look at what the evidence says.

What  do we know?

We’ve known for a long time now that alcohol increases the risk of mouth cancer, and it’s not a particularly new concept. So the idea that using mouthwash that contains alcohol could increase the risk of mouth cancer does make sense, but the evidence around this link is inconsistent.  Scientists have looked at this many times before, and found that there is no real evidence to suggest that using mouthwash can increase the risk of mouth cancer.

So where’s the ‘sufficient’ evidence?

Let’s take a closer look at how the researcher came to find ‘sufficient evidence’ for this link.  This new Australian study is actually a review of the existing evidence, although similar reviews in the recent past have concluded that there is not enough evidence for a link between alcohol-containing mouthwash and cancer.

This new review places a lot of emphasis on a large study carried out in Latin America and Central Europe in 2007.  The study looked at the link between many elements of oral hygiene and mouth cancer. The investigation of a link between mouthwash use and mouth cancer formed only a small part of the study.

Although the findings did suggest that mouthwash use may increase the risk of mouth cancer, the researchers warned that their findings should be ‘interpreted with caution’, largely because they did not record the alcohol content of the mouthwash, the length of time that people had used mouthwash, or how long they held it in their mouth. The researchers on the Latin American and Central European study conclude that ‘the alcohol content of certain mouthwashes may be a causal agent’ for mouth cancer.  This is not the same as there being ‘sufficient’ evidence.

When scientists talk about having sufficient evidence, we would expect to find lots of studies that are saying the same thing and that can explain why there might be a link.  In this case, although we can see why there might be a link, the research is not telling us the same thing. There are only a small number of studies and they largely disagree. The evidence about mouthwash and mouth cancer is not consistent let alone ‘sufficient’.

The point is…

Despite what the Australian study claims, there is still not enough evidence to suggest that using mouthwash that contains alcohol will increase the risk of mouth cancer.  The most important risk factors for mouth cancer are smoking and drinking more than three units of alcohol a day.

Yinka Ebo

Yinka is a Health Information Officer at Cancer Research UK

References:

MJ McCullough, CS Farah (2008). The role of alcohol in oral carcinogenesis with particular reference to alcohol-containing mouthwashes Australian Dental Journal, 53 (4), 302-305 DOI: 10.1111/j.1834-7819.2008.00070.x

N. Guha, P. Boffetta, V. Wunsch Filho, J. Eluf Neto, O. Shangina, D. Zaridze, M. P. Curado, S. Koifman, E. Matos, A. Menezes, N. Szeszenia-Dabrowska, L. Fernandez, D. Mates, A. W. Daudt, J. Lissowska, R. Dikshit, P. Brennan (2007). Oral Health and Risk of Squamous Cell Carcinoma of the Head and Neck and Esophagus: Results of Two Multicentric Case-Control Studies American Journal of Epidemiology, 166 (10), 1159-1173 DOI: 10.1093/aje/kwm193

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Comments

Phil Harris January 4, 2010

Has anyone studied the rate of mouth cancer in wine and spirit tasters?

Good Grief October 13, 2009

Scientists should be cautious before making bold claims, but they shouldn’t be afraid to make an educated guess, either. No mouthwash, with or without alcohol, is safe if you’re worried about cancer. Brush with baking soda once in a while and clean your breath that way. Rinsing with mouthwash is like doing a science experiment in your mouth.

Furthermore, this whole article sounds like backpedalling to me. All the author seems to say is that, “There is not enough evidence to link the ALCOHOL in mouthwash to mouth cancer.” But what about the other active ingredients? What about the chemicals that leach into the mouthwash from the plastic bottle that it is shipped in? What about chemical overload in general? It’s bizarre that no one is asking if all the other weird things being gargled WITH the alcohol aren’t part of the problem!

Clare March 19, 2009

The alcohol (ethanol) used in a mouthwash is not distilled alcohol. It’s the distillation process where you get urethanes which are the potentially carcinogenic factors.

Dental Student January 27, 2009

As a dental student I would not advise LONG-TERM use of alcohol mouthwash. As with most things it is a matter of everything in moderation. Im sure that there would be an increased RISK (small to begin with) of cancer if I were to brush my teeth five times a day for five minutres with a high flouride toothpaste.

In my experience few people use mouthwash LONG-TERM and DAILY, although maybe that is the very reason they dont need to come and have their teeth filled!? Common sense please.

Ed Yong January 27, 2009

There is no reason to believe that non-alcoholic mouthwashes could affect the risk of cancer. But as we said above, there’s no strong evidence yet that alcoholic mouthwashes pose a risk either.

w cheng January 23, 2009

So mouth wash without alcohol is safe? My kids are using that. Please kindly provide some guidance.

Sammiie's comment dirk was watching January 20, 2009

i believe that mouthwash does not increase the risk of cancer even though it does affect the oral bacteria, this does not mean it will lead to cancer :D

Laura and katie January 16, 2009

The article has shown that the study was not carried out properly, as the results and the factors, such as the concentration of the alcohol, were not recorded, so there is no real evidence of the link between mouthwash and oral cancer.

daedalus2u January 14, 2009

I think this result is accurate and that mouthwash does increase oral cancers, and probably by the same mechanism that alcohol consumption does, that of disturbing the normal oral bacteria.

http://www.ncbi.nlm.nih.gov/pubmed/18793740

An extremely important function of oral bacteria is to reduce nitrate in saliva (concentrated ~10x over plasma) to nitrite. That nitrite can reach 2 mM/L in saliva following a high nitrate meal (~100 grams of lettuce).