On 10 Jun 2005 10:02:58 -0700, [email hidden] wrote in
<news:[email hidden]> on
sci.med.nutrition :
Quoted message said:Chris Malcolm said:[15 quoted lines suppressed]
Trans fat in milk, AFAIK, is _not_ the same chemically as trans fat
made by man. It has its own special name even. It's called rumenic
acid. There are many different types of CLA (a trans fat). If you
look at studies, some at least will show that natural CLA (rumenic
acid) is more beneficial than commercially made CLA.
That's what the "Campaign against trans fats in food" web site says too,
about natural trans fats.
http://www.tfx.org.uk/page62.html
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Naturally occurring trans fats
Some trans fats occur naturally in the digestive system of ruminant animals
such as cows, sheep and goats. Some trans fat is therefore present in meat,
milk and other dairy produce.
According to the The US Department of Agriculture, these trans fats make up
15 to 20 percent of the total trans fat intake in our diet. Others believe
that these natural trans fats occur at much lower levels. According to Fran
McCullough, author of The Good Fat Cookbook, these natural trans fats occur
at "minute" levels, and our total intake of trans fats has increased by 25
times over the introduction of hydrogenated vegetable oils.
Most importantly, however, naturally occurring trans fats do not share the
harmful properties of the synthetic trans fat resulting from hydrogenation.
For example, Conjugated Linoleic Acids (CLA), are health-promoting with
specific roles to play in our bodies.
Thus, COMA reports,
"Willet et al reported findings from the Nurses Health Study, a
prospective study involving more than 85,000 women, showing that intake of
trans fatty acids was significantly and independently associated with
incidence of CHD. The association was only seen for for trans fatty isomers
from hydrogenated vegetable oils. The mainly different trans isomers from
ruminant fats did not show such an association. A case-control study in 239
people suffering an acute myocardial infarction found that after adjustment
for age, sex and energy intake, intake of trans fatty acids was directly
related to risk of myocardial infarction. Those with the highest intake of
trans fatty acids had twice the risk of myocardial infarction as those with
the lowest intakes after adjusting for other cardiovascular risk factors.
As with the Nurses Health Study, the association was only seen for trans
isomers from partially hydrogenated vegetable oils."
From: Department of Health (1994) Nutritional Aspects of Cardiovascular
Disease, Report of the Cardiovascular Review Group of the Committee of
Medical Aspects of Food Policy (COMA). Report No. 46. London: HMSO. See
longer extracts about trans fats here.
The Danish Nutrition Council similarly states in The influence of trans
fatty acids on health - 2003 update, 10/03/2003 (Summary):
"Available data suggest that ruminant trans fatty acids, especially
concerning the effect on cardiovascular risk, do not possess the same
unfavourable effects as industrially produced trans fatty acids. The
content of trans fatty acids in industrially hydrogenated fats may reach 60
percent of the fatty acids. The equivalent number for ruminant fat is 2-5
percent."
Likewise, according to the International Dairy Federation (submission to
the World Health Organisation, June 2002):
There is a need to differentiate the trans fatty acids. We agree on the
negative impact of hydrogenated oils and fats but natural trans fatty acid
like CLAs (conjugated linoleic acids) present in meat and dairy products
play a specific role on plasma lipids and cardiovascular function. [Khosla
P, Fungwe TV, Conjugated Linoleic Acid: Effects on Plasma Lipids and
Cardiovascular Function; Curr Opin Lipidol 2001, 12 :1231-4]
CLAs (conjugated linoleic acid) have anticarcinogenic properties,
blocking tumour growth and metastasis from the breast (12,13). In the
Kuopio Breast Cancer Study, breast cancer patients had lower serum CLA,
myristic and trans vaccenic acid (precursor of CLA) than control [Aro A et
al, Inverse Association Between Dietary and Serum Conjugated Linoleic Acid
and Risk of Breast Cancer in Postmonopausal Women; Nutr and Cancer 2000,
38: 151-7.]
From: Consultation with Industry Organisations on Diet, Nutrition and
the Prevention of Chronic Diseases - Comments from the International Dairy
Federation, 15 June 2002. Download (.doc) here.
In conclusion, by eating meat and dairy products, you will be eating small
amounts of naturally-occurring trans fats, but among these are trans fats
which are positively beneficial to health. The harmful effects attributed
to synthetic trans fats arising from industrial processing are not
associated with naturally occuring trans fats.
However ...
However these clear and straightforward facts have not prevented the food
industry and its advocates from conflating these two very different kinds
of trans fat. By failing to distinguish between the 'good' natural trans
fats, and the 'bad' synthetic trans fats, they purport to show that:
* our intake of synthetic trans fats is only adding an additional
fraction of trans fat to what has been in the natural human diet for
millenia.
* even if we stopped eating all the synthetic trans fats, we would
still be eating trans fat anyway, so what's the point?.
One example of this conflation comes from the UK's Food Standards
Agency, which wrote in a letter of 21 September 2004 that
"The main issue with hydrogenated fats relates to their content
of trans unsaturated fatty acids (trans fats). These trans fats occur in
nature in dairy produce and the flesh of ruminants, e.g. beef, lamb."
The Co-op likewise stated in a letter, referring to a report (which
we have been unable to track down) by the industry-friendly British
Nutrition Foundation, that
Studies have failed to show that trans fatty acids are a
significant factor contributing to coronary heart disease. The report did
not find any evidence that the trans fatty acids found in industrially
hardened oils are different to those produced in nature and found in
mutton, beef and milk fats, including butter. A Senior Nutrition Scientist
at the BNF has stated that Trans fatty acids from different sources are
basically the same but the amounts in similar products may differ.
It is really intolerable that these respected orgnisations should be
so ready to mislead and obfuscate in this way.
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