Re: Canola oil does not increase lipid peroxidation

On Fri, 01 Jul 2005 17:05:59 GMT, David Harmon wrote in
<news:42f551ee.229822875@xxxxxxxxxxxxxxxxxxxxxxx> on sci.med.nutrition :

> On Wed, 29 Jun 2005 22:04:08 +0200 in sci.med.nutrition, Enrico C
> <use_replyto_address@xxxxxxxxxxxxx> wrote,
>>According to the Harvard School of Public Health, canola oil has no trans
>>fats,
>>http://www.hsph.harvard.edu/nutritionsource/fats.html
>>
>>
>>but according to nutritionist Mary Enig
>>
>>"Canola oil, processed from a hybrid form of rape seed, is particularly
>>rich in fatty acids containing three double bonds and the shortening can
>>contain as much as 50% trans fats."
>>
>>"The Oiling of America"
>>http://www.westonaprice.org/knowyourfats/oiling.html
>>
>>
>>Who is right?
>
> Quoting out of context is dishonest.

Or ill-picked, in this case.

> The word "shortening" there
> refers to the result of the catalytic hydrogenation process that Enig
> is discussing in that eight-paragraph section of the paper, and not to
> the original un-hydrogenated oil.

You are right. My bad.

I believe another sentence in the same paragrah would be a more relevant
quote on canola oil as such (as opposite to the shortening), in fact.

http://www.westonaprice.org/knowyourfats/oiling.html
[...]
"Trans fats of a particularly problematical form are also formed during the
deodorization of canola oil, although they are not indicated on labels for
the liquid oil.12a"

It is at the end of the same paragraph, but it refers to the liquid oil.

Here are the references.

http://www.westonaprice.org/knowyourfats/oiling5.html#12a
12a. Researchers at the University of Florida at Gainsborough found trans
levels as high as 4.6% in processed canola oil. (S. O'Keefe and others.
Journal of Food Lipids1994;1:165-176.) The conversion of omega-3 fatty
acids to trans fats can be prevented by certain careful processing methods.
(JL Sebedio and others. European Journal of Clinical Nutrition 2000
Feb;54(2):104-13.


And here is the Sebedio study stating, indeed, that "Trans 'free' rapeseed
oil, rich in alpha-linolenic acid, *can* be produced by careful
deodorization."
I guess they mean "cold pressed" canola oil, right?.
I also gather, from some web sites, that cold-pressed canola oil *must* be
served cold in order to preserve its benefits (in fact, Juhana recommended
it in salads, not for cooking).
[Still, some sellers suggest that "cold-pressed canola oil" be used in
baking!
http://highwoodcrossing.com/coldpressed_oil.html
"To use fresh canola oil in baking, substitute it straight across in any
recipe calling for vegetable oil." ]


http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=10694780&query_hl=6

Eur J Clin Nutr. 2000 Feb;54(2):104-13. Related Articles, Links

The effect of dietary trans alpha-linolenic acid on plasma lipids and
platelet fatty acid composition: the TransLinE study.

Sebedio JL, Vermunt SH, Chardigny JM, Beaufrere B, Mensink RP,
Armstrong RA, Christie WW, Niemela J, Henon G, Riemersma RA.

INRA, Unite de Nutrition Lipidique, Dijon, France.

OBJECTIVE: To collect (i) baseline data and (ii) execute a large
multicentre study examining the effect of trans alpha-linolenic acid on its
incorporation into plasma lipids and on risk factors for coronary heart
disease. DESIGN: Male volunteers were recruited and the habitual diet
assessed by a 4-d weighed record. Fatty acid composition of plasma and
platelet lipids were determined by gas chromatography at baseline. After a
6 week run-in period on a trans 'free' diet, male volunteers were
randomised to consume 0.6 % of energy trans alpha-linolenic acid or to
continue with a diet 'low' in trans alpha-linolenic acid for 6 weeks.
SETTING: Three European university research departments supported by the
research and development departments of the food industry. Subjects: Male
volunteers (88) recruited by local advertisement. METHODS: Replacement of
30 % of the fat of the habitual diet by margarine, oil and foods. Rapeseed
oil was deodorised especially to produce the trans 'free' and 'high' trans
foods for this study. The incorporation and conversion of trans
alpha-linolenic acid into plasma lipids and platelets was assessed by gas
chromatography and dietary compliance was verified by 4-d weighed record.
Results: Less trans alpha-linolenic acid isomers are incorporated into
human plasma lipids in French volunteers than in Dutch or Scottish
volunteers consuming their habitual diets. Trans 'free' alpha-linolenic
acid-rich oil can be produced by careful deodorization during refining. The
'high' trans diet provided 1410+/-42 mg/d trans isomers of alpha-linolenic
acid, whilst the 'low' trans group consumed 60+/-75 mg/d. The change in
plasma lipid and platelet fatty acid composition documented that trans
linolenic isomers are incorporated and converted to a trans isomer of
eicosapentaenoic acid. Only the 15-trans alpha-linolenic acid is
incorporated into plasma cholesteryl esters. The group consuming low trans
diet had a slightly higher intake of fat, especially saturated and
monounsaturated fat. CONCLUSIONS: Trans 'free' rapeseed oil, rich in
alpha-linolenic acid, can be produced by careful deodorization. Dietary
records show good compliance. Dietary trans isomers of alpha-linolenic acid
are incorporated in plasma lipids and converted to long-chain
polyunsaturated fatty acids. Their effects on risk factors for coronary
heart disease and their metabolism will be reported elsewhere. Sponsorship:
European Commission (FAIR 95-0594 grant). European Journal of Clinical
Nutrition (2000) 54, 104-113

Publication Types:

* Clinical Trial
* Randomized Controlled Trial


PMID: 10694780 [PubMed - indexed for MEDLINE]

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Relevant Pages

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