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From: sdyer@bbncca.ARPA (Steve Dyer)
Newsgroups: net.med
Subject: Re: Partially Hydrogenated Oils
Message-ID: <536@bbncca.ARPA>
Date: Tue, 31-Jan-84 02:10:23 EST
Article-I.D.: bbncca.536
Posted: Tue Jan 31 02:10:23 1984
Date-Received: Wed, 1-Feb-84 01:15:38 EST
References: <239@pyuxss.UUCP>, <859@ihuxl.UUCP> <1148@sdccs5.UUCP>
Organization: Bolt, Beranek and Newman, Cambridge, Ma.
Lines: 30

Regarding commercially hydrogenated fats as being detrimental because
they contain unnatural isomers:

Because the hydrogenation of unsaturated fats involves the conversion of
double bonds to single bonds, there can be no problem with the production
of unwanted isomers during the process of hydrogenation.  That is,
carbons cannot rotate around a pair of double bonds, and so for any
molecule asymmetric around a double bond, there are two steric possibilities:

X      H                                X      X
 \    /                                  \    / 
  C==C          (trans)                   C==C          (cis)
 /    \                                  /    \ 
H      X                                H      H

Adding hydrogen, however, destroys this asymmetry, regardless of whether
it's done by an enzyme or by a catalyst like nickel.  You end up with

X-CH-CH-X
    2  2

regardless of which isomer you started out with.  Saturated fats are
"bad" because they predispose a population towards increased cholesterol
levels, which have been implicated in arteriosclerosis and heart disease.
As far as your body is concerned, "Crisco" is no worse than lard, given equal
saturation levels.
-- 
/Steve Dyer
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