My 17 year old daughter is very clever and knows much more about
science than I do. She goes out with friends on occasion and, to my
mind, has far too much alcohol. I tell her I know this because her
breath smells bad (and her bedroom stinks in the morning!), of what I
think are ketones. She says this cannot be right (smartarse!) as
alcohol comes in two forms - primary and secondary - and the alcohol
we drink is
primary which does not break down into ketones. I need to persuade her
that I am right and that her bad breath and smelly room do truly
indicate that she is drinking too much. Where can I find some
unarguable! research to back me up?

Dear briesmith:

Thank you for your question!

Both you and your daughter is correct. Drinking alcohol is better
known as ethanol, and it is indeed a primary alcohol. Primary alcohols
break down through oxidation into structures called aldehydes, rather
than the ketones that come from oxidation of secondary alcohols. The
aldehyde produced by ethanol, or drinking alcohol, is known as
ethanal. Ethanal does not have a displeasing odor, but rather an
apple-like smell.
Source1: http://chemed.chem.purdue.edu/genchem/topicreview/bp/2organic/alcohols.html
Source2: http://chemed.chem.purdue.edu/genchem/topicreview/bp/2organic/aldehyde.html
Source3: http://www.xrefer.com/entry/641002

So your daughter is correct about the chemistry of this question.
However, alcohol does contribute heavily to bad breath, due to its
mouth drying effects, according to several independent sources on
halitosis.

"Alcohol, alcohol-containing mouthwashes, heavy exercise and fasting
can all result in a dry mouth and worsen a bad breath problem."
http://www.embarrassingproblems.com/pages2/breath_1.htm

"Alcohol causes horrible bad breath and lousy taste. Alcohol makes the
mouth extremely dry and will cause instant bad breath. It doesn't
matter if the alcohol is in wine, beer or even commercial mouthrinse.
In addition, several studies have shown that too much alcohol over a
period of time can destroy oral tissue."
http://www.freshbreathcures.com/foods.html

"Alcohol is a very good drying agent, and therefore should be avoided
when ever possible. It drastically increases the numbers of anaerobic
bacteria and is a major cause of dry mouth. Apart from this fact
alcohol is known to cause pre cancerous changes to oral tissue. This
also includes the alcohol found in most commercial mouthrinse."
http://www.freshbreathcures.com/causes.html

Google Search Strategy:
alcohol bad breath ketones
alcohol "bad breath"
alcohol primary secondary
smell OR odor aldehydes
smell OR odor ethanal

I hope this helps. If you need any clarifications, please don't
hesitate to ask. I would be more than happy to assist you further.

Best Regards,
blader-ga

---

Request for Answer Clarification by briesmith-ga on 01 Nov 2002 05:55 PST

Hello Blader-ga

Thanks for your reply. It seems that I'm on the wrong track and she's
right. What I don't understand from your answer is why, if the cause
is general mouth drying and resulting bad breath from bacterial
activity in the dry mouth, why people with bad breath due to
over-indulgence always give off the same, unmistakeable odour which is
very different from standard bad breath or halitosis. I remain
convinced that the odour is due somehow to the processing of alcohol
and is a by-product of that activty and not just general bad beath
caused by a dry mouth which is the sort of thing heavy snorers suffer
from. This is relieved immediately by drinking water and cleaning
one's teeth; the smell I'm talking about lasts all day (and heavy
snorers don't stink out their rooms). I think we're still missing
something in our chemistry here!

---

Clarification of Answer by blader-ga on 01 Nov 2002 18:21 PST

Dear briesmith:

Thanks goes to Alexander-ga for the information in the comments below,
it appears to be right on point. He is correct. Acetic acid is another
name for the aldehyde ethanal, which is the oxidation of ethanol. I
maintain that the principle reason for the bad breath is due to the
diuretic properties of alcohol. However, according to the Berkeley
Smell Database, ethanal (acetic acid) may not be as pleasant an odor
at all. In fact, it can smell like vinegar.
Source: http://mc2.cchem.berkeley.edu/Smells/Acetic_acid.html

I suspect that it is this combination of vinegar odors combined with
the mouth drying effect of ethanol that is responsible for the
distinct smell.

If you have any more clarifications requests,  please don't hesitate
to ask.

Best Regards,
blader-ga

Bit put off by the poor English and spelling ("both you and your
daughter is(!) correct", breadth for breath) and by the unwillingness
to take on the second stage of the query where pat answers no longer
suffice and where further informed research was needed. I am not sure
that reference sources that are proprietary and trade promoting
(freshbreathcures) with little standing as academic work should be
relied on. At the end of the day, however, it is useful to know that
this resource exists and I will almost certainly use it again in the
future.

Incomplete oxidation of the alcohol:

"More than 90% of the ethyl alcohol that enters the body is completely
oxidized to acetic acid. This process occurs primarily in the liver.
The remainder of the alcohol is not metabolized and is excreted either
in the sweat, urine, or given off in one’s breadth [sic]. The latter
provides the basis of the breathalizer test used in law enforcement
and is the reason one can smell alcohol on the breath of someone who
has been drinking recently."
http://chemcases.com/alcohol/alc-06.htm (terms: alcohol smell breath
chemistry)

Not sure if this would address morning-after issues, as any excreted
alcohol should have evaporated by then.

(For rating purposes, pretend Blader found this. We're all friends
here, I was just curious myself. :)

"Acetic acid is another
name for the aldehyde ethanal"

This is factually incorrect. Acetic acid is another name for Ethanoic acid.
Acetaldehyde is another name for ethanal.
The oxidation goes like this:
Ethanol -> ethanal (acetaldehyde) -> Ethanoic acid (Acetic acid, vinegar acid)

If you and your daughter disagree about her drinking, you might find
"Children, Alcohol & Parenting" of use. It's located at
http://www2.potsdam.edu/alcohol-info/ChildrenAndParenting.html