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From: B. Harris)
Subject: Re: Problem metabolizing butter?
Date: 29 Mar 1999 09:47:07 GMT

In <7dnebr$djf$> "Tom Evans"
<> writes:

>When I eat toast with butter on it, I feel strange, like I've got alcohol
>in my system. Also, my urine has an unusual smell for a while afterward.
>Does this raise any red flags in terms of metabolic/renal function?

   Butter contains butyric acid (that's where the stuff got it's name,
in fact), and if you have levels of this too high you can in theory
with your p450 system get rid of it by hydroxylating some of this to
gamma hydroxybutyrate (GHB), which is the chemical so much in the news
as a "drug of abuse" and "date-rape" drug.  Nevermind that it's been
available in Europe for years and still is, and that you could buy it
flat out in health food stores up to 1990.  It's now illegal on par
with LSD in some states.  But it does make you feel a bit like alcohol,
and perhaps you're especially sensitive to this.

   Hydroxybutyrate is odorless, as are butyrate salts in general.  The
free butyric acid, however (which you'd see in acidic urine) smells
like rancid butter, and indeed (surprise) is what makes rancid butter
smell rancid. If that's what you smell, it might suggest you have
problems metabolizing butyrate, and it's building up in your system
when you eat it, thus forcing your body to deal with it by alternative
oxydative means.

   Now, the body makes fats using butyryl-ACP, and this is such a basic
process it's hard for me to imagine anybody having trouble using this
stuff.  So perhaps the defect is in your ability to activate butyrate
to butyryl-ACP.  I really don't know HOW the normal body deals with
butyrate or butyric acid, but my Merck Index says the LD50 (lethal dose
half the time) in rats is about 9 grams/kg, which is not greatly
different than the 14 g/kg for plain old ethanol (drinking alcohol).
It's about midway in toxicity between ethanol and isopropanol (rubbing
alcohol).  This suggests that the body does have a hard time with it
normally, and doesn't just feed it into fatty acid synthesis with no
problems.  But what the enzymes involved are, I have no idea.

   Warning: all of the above stuff about your possible biochem defect
is total blue sky speculation from somebody with no special knowledge
of the area.  It's the kind of thing you get free on the internet, and
darn well worth it.  You might just be a guy who smells butyrate
unusually well, and gets sick to his stomach and dizzy from it.  There
are lots of examples  of this kind of thing for lots of chemicals, and
none of them have anything to do with metabolic problems.

                                         Steve Harris

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