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Tuesday, 12 April 2016

Swapping saturated fat for vegetables oils doesn’t reduce risk of heart disease, study suggests

Replacing saturated fats with vegetable oils rich in linoleic acid does not reduce the risk of heart disease or help people live longer despite lowering their blood cholesterol, a study suggests.

Although many studies support the theory that swapping saturated fat for vegetable oils rich in linoleic acid cut cardiovascular deaths by lowering blood cholesterol levels it has never been casually demonstrated in a randomised controlled trial, said researchers.

The team led by Christopher Ramsden from the National Institutes of Health and University of Carolina re-examined data from the Minnesota Coronary Experiment, a large randomised controlled trial which followed 9,423 residents of one nursing home and six state mental hospitals for four and a half years from 1968.

While people on the study diet swapped saturated fat for the oils rich in linoleic acid the control group ate a diet high in saturated fat.

Their research published in the British Medical Journal (BMJ) found that replacing saturated fat with linoleic acid – such as corn, sunflower, safflower, cotton seed or soybean oils – lowered serum cholesterol but did not lead to a lower risk of death from coronary heart disease.

Instead, paradoxically trial participants who had greater reductions in their serum cholesterol had a higher, rather than a lower risk of death.

The researchers said that although limited the evidence from the randomised trials showed “no indication of benefit on coronary heart disease or all cause mortality from replacing saturated fat with linoleic acid rich vegetable oils.”

They said one reason why the reduction in serum cholesterol did not lead to improved outcomes was that replacing saturated fat with linoleic acid decreases low density lipoprotein which is “often thought a causal mediator of coronary heart disease”.

High intakes of linoleic acid could also have adverse effects on people who are prone to linoleic acid oxidation, such as heavy smokers or drinkers and older people.

Researchers also pointed out that linoleic acid mainly comes from highly concentrated vegetable oils used in cooking, frying and heavily processed food in modern diets and is much higher than the amount consumed in “natural diets” without any addition of oil.



The full study can be accessed here:  http://www.bmj.com/

Graham

10 comments:

Anonymous said...

So are you saying use lard, extra virgin olive oil?

Sue

Lowcarb team member said...

Sue said...
So are you saying use lard, extra virgin olive oil?

It's the conclusion of the study authors not me though I do agree with the findings, extra virgin oil is fine but beware of the mass produced lard you find in the shops that's gone through a process that includes bleaching

Graham

Anonymous said...

They bleach lard? I didn't know that. I know the way margarine is made is highly chemically based. Pure lard must be available from some stores. I will have a look around.
Thanks

Sue

Lowcarb team member said...

Sue said...
They bleach lard? I didn't know that. I know the way margarine is made is highly chemically based. Pure lard must be available from some stores. I will have a look around.

Hi Sue, best bet is if you have any butchers in your area see if they render their own lard in the traditional way

Graham

Lowcarb team member said...

Hi Sue ... butting in on your conversation with Graham. Obviously try the butchers in your area, but this article may also help you - it tells how to render your own lard
http://bakerbettie.com/how-to-render-lard/

All the best Jan

Anonymous said...

Thanks Graham and Jan, I will look further into this.

Sue

Spittin'chips said...

"Unfortunately I can't even access the study abstract due to the BMJ site being restricted to HCP's
"

are you sure, Graham? The whole thing is available for me at that link - http://www.bmj.com/content/353/bmj.i1246

I can email you the pdf if you like.

Lowcarb team member said...

Spittin'chips said...
"Unfortunately I can't even access the study abstract due to the BMJ site being restricted to HCP's
"

are you sure, Graham? The whole thing is available for me at that link - http://www.bmj.com/content/353/bmj.i1246

I can email you the pdf if you like.


It's OK the link within the post is now working I've also edited the post and included a direct link to the BMJ article

Don't know what was going on last night the link was taking me to the BMJ login page, must have been some sort of a glitch

Thanks
Graham

chris c said...

Vindicates the original Rose Corn Oil Trial

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2166702/

after a mere 50 years

chris c said...

Forgot to add, Michael Eades has some technical reasons why Omega 6 oils may not be so good

https://proteinpower.com/drmike/2016/02/03/will-the-new-dietary-guidelines-fatten-us-even-more/