New data from old study reveals that reducing saturated fat in favour of ‘vegetable’ oils increases risk of heart attack and can have fatal consequences

Conventional nutritional ‘wisdom’ has it that saturated fat (found in foods such meat, eggs, dairy products, coconut and palm oil) is bad for heart health, while ‘polyunsaturated’ fats (including ‘vegetable’ oils) are good. These concepts emerged decades ago and were mostly based on the impact of these fats on cholesterol levels. There’s a big potential problem here, though: the impact that foods (or anything else) have on cholesterol is not the important thing, it’s the impact that they have on health that really counts.

In 2010, a team of research based in the US reviewed the evidence in which polyunsaturated fats were given to individuals and the effects on cardiovascular disease risk (e.g. heart attacks) were assessed [1]. This review made some attempt to distinguish between the effects of the two main forms of polyunsaturated fat: omega-6 (found in ‘vegetable’ oils such as sunflower oil and safflower oil) and omega-3 (found most abundantly in oily fish such as salmon, trout, mackerel and herring).

This review found that upping omega-6 intakes did not lead to beneficial outcomes for health. However, a mix of omega-3/omega-6 did. In fact, there was a trend (though not statistically significant) for omega-6 supplementation to increase cardiovascular disease risk. The authors concluded: “Advice to specifically increase [omega-6 polyunsaturated fat] intake….is unlikely to provide the intended benefits, and may actually increase the risks of [coronary heart disease] and death.

This evidence was revisited this week by the same team in a study published in the British Medical Journal [2]. The authors added to their previous review with new data that they had extracted from an old study. The study in question, which took place between 1966 and 1973, is known as the ‘Sydney Diet Heart Study’. In this research, about 220 men aged 30-59 were instructed to reduce saturated fat intake and increase polyunsaturated fat intake. The men were supplied with safflower oil and safflower oil-based margarine (both rich in the omega-6 fat known as linoleic acid). A similar number of men got no dietary instruction and acted as controls.

The results of this study were reported in 1978. The men who cut back on saturated fat and boosted their omega-6 intake were found to be at increased risk of death. Effects of the diet on risk of death from cardiovascular disease (including heart disease) were not reported. In this week’s review, the researchers go back to this data to extract this information.

Their analysis confirms the original report of increased risk of death in men on the omega-6-rich diet. Risk of death was elevated by 62 per cent.

However, new findings previously unearthed (or undeclared) were that the men eating the ‘heart-healthy’ diet were at increased risk of dying from cardiovascular disease and heart disease (increases of 70 and 74 per cent respectively).

So, the very diet designed to reduce the risk of heart disease and fatal heart attack was found to have the opposite effect: It killed men, and specifically from heart disease.

The inclusion of this data in the wider evidence base made difference to the original finding from 2010 that omega-6 fat supplementation did not benefit health. Here’s the authors’ conclusions:

Advice to substitute polyunsaturated fats for saturated fats is a key component of worldwide dietary guidelines for coronary heart disease risk reduction. However, clinical benefits of the most abundant polyunsaturated fatty acid, omega 6 linoleic acid, have not been established. In this cohort, substituting dietary linoleic acid in place of saturated fats increased the rates of death from all causes, coronary heart disease, and cardiovascular disease. An updated meta-analysis of linoleic acid intervention trials showed no evidence of cardiovascular benefit. These findings could have important implications for worldwide dietary advice to substitute omega 6 linoleic acid, or polyunsaturated fats in general, for saturated fats.

You may wish to take this study and the authors’ conclusion and wave them under the face of anyone suggesting that you need to swap ‘deadly’ butter for ‘healthy’ margarine or vegetable oils. There is no good evidence that this is beneficial to health, and there never was. If fact, we have at least some evidence that this oft-touted nutritional strategy actually jeopardises health and life itself.


1. Ramsden CE, et al. n-6 fatty acid-specific and mixed polyunsaturate dietary interventions have different effects on CHD risk: a meta-analysis of randomised controlled trials. Br J Nutr 2010;104:1586-600

2. Ramsden CE, et al. Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis BMJ 2013;346:e8707

32 Responses to New data from old study reveals that reducing saturated fat in favour of ‘vegetable’ oils increases risk of heart attack and can have fatal consequences

  1. mhikl 6 February 2013 at 11:03 pm #

    I figured this out long time ago. Can’t see how our Cro-Magnon brethren had the means to slap together omega 6 from seeds without messing up the cave and no way the lady-Mognons would ever have have put up with such experiments.

  2. Jonathan Bagley 7 February 2013 at 2:56 am #

    Yes, I read that. In a decade the Government might agree. In the mean time it seems that a bunch of cooks and celebrities will have pressurised it into some crazy scheme of dietary advice in schools, probably including the confiscation of cheese sandwiches from lunch boxes, as happened in Wigan in 2010, by “school food-enthusiasts.”

  3. Bo 7 February 2013 at 11:33 am #

    ‘deadly’ butter

    Some other saturated, semi-saturated fats has great potential health benefits such as good quality coconutoil (lauric acid), Red palm oil (tocotrienols, a unique form of vitamin E)

    If any of this holds true; no wonder they want to keep saturated
    demionized as “deadly” To much to loose for big business if people use natural remedies instead of all pills, vaccines and other expensive stuff.

  4. David M Driscoll 7 February 2013 at 4:16 pm #

    Have you looked at the article critically? I found these comments helpful

    “However, new findings previously unearthed (or undeclared) were that the men eating the ‘heart-healthy’ diet were at increased risk of dying from cardiovascular disease and heart disease (increases of 70 and 74 per cent respectively).” Nice way to spin statistics to maximise the impact!

  5. Dr John Briffa 7 February 2013 at 4:33 pm #

    David M Driscoll

    Please be specific: which comments did you find helpful, and why?

    Nice way to spin statistics to maximise the impact!

    Really? I just reported precisely what the authors of the study report.

  6. mhikl 8 February 2013 at 2:28 am #

    I suspect that the biggest problem in food studies is an understanding and acceptance of real scientific principles, particularly the skill to leave one’s biases behind and the fear for one’s job and respect should one go against the accepted norms of one’s discipline and employer.
    I do find most paleo sites do seem to be more open to challenges to what are their perceived truths, especially when there is good scientific studies or even valid arguments involved; for example, questions that are raised as to measurable value of coconut oil. I’m pretty good at sensing what feels good or seems to affect me positively, negatively and neutrally and though I like the fragrance of coconut oil, I don’t sense and benefits compared to raw beef fat and butter. I still use it nonetheless.
    Recently I have dropped garlic and onions after seeing a Youtube piece on the dangers of garlic and onions which sent me on a quest to see what else I could find on the subject. I found enough that I stopped using them as, though I had been viewing them as neutral regarding how I felt and sensed (and being swayed by conventional descriptions regarding their healthfulness), I realised that there has always been a concern hiding at the back of my thoughts—I never really liked them, raw, cooked or dried. I haven’t missed them in my Ketogenic Raw diet and my occasional cooked additions. I am now re-evaluating my spices and herbs.
    Regarding sensing: When I used (and still do to a degree) Dr Peter D’Adamo’s Blood type diet for O Bloods, I was amazed to find that the majority of foods indicated as not good for my blood type, I usually chose not to eat them: since childhood I felt oranges and strawberry hurt my tummy so I rarely ate them and as an adult, never. As a child and adult I detested Brussels sprouts and disliked cauliflower, yet I ate both keeping a frozen bag of B-s at all times in my freezer eating six of the foul little cabbages every Sunday. With glee I tossed that bag of foul smell and have never had another one since.

  7. Paul 8 February 2013 at 9:56 am #

    Am I the only person who winces when a TV celebrity chef cuts the fat off a piece of meat, and apologises when he uses butter in a dish?

    The problem with saturated fat is that we are now two generations into ‘healthy eating advice’ concerning saturated fat and the general public also confuses saturated fat with obesity and the myth of cardio-vascular disease with the thought that saturated fat is somehow more calorific than vegetable oils. Indeed, the lack of education on the subject means that the public thinks that fats are bad, but oils are good. In my day at school in the 1970s, we were taught that that fats and oils were one group, but today it appears that people are educated that fats and oils are differentiated.

    How long will it take to undo the received wisdom that saturated fat is poison? A long time I fear.

  8. John Walker 8 February 2013 at 12:31 pm #

    Paul… No you are not the only one. I have given up watching TV food programmes, and the obesity related shows, because the constant attack on fat and fatty foods causes my blood pressure to hit the sky. I become incensed when I hear the misconceptions being touted. In the case of food advertisements, law-breaking occurs, with the constant references to ‘fat being bad for us’. It just isn’t so, isn’t and I think there is abundant evidence to prove that. I could report them to the Advertising Standards Agency I suppose, but I would be laughed at, would I not? The fact is all of these vegetable oils are processed and we know what processed food does.

  9. John Cooney 8 February 2013 at 12:33 pm #

    This is taken from the study I believe, “The study used Miracle margarine as a source of polyunsaturated fat. In the 1960s, when this study began, Miracle margarine contained approximately 15% trans fatty acids, which have the worst effect on heart disease risk of any fat. The adverse effect of the intervention in this study was almost certainly due to the increase in trans fatty acids in the diet.

    Recent, well conducted studies indicate that replacing saturated fat with polyunsaturated fats lowers heart disease risk and this is widely accepted.”

    Hmmmm, I wonder what the truth is….

  10. Stuart Ward 8 February 2013 at 12:42 pm #

    I believe a big part of this confusion is that many people have lost there common scene to adverts and magazines. My cat looks at flora or benacole as though its poison yet he will happily lick up some butter. Our western attitude is towards instant gratification and results. If flora say they can make us healthy just by eating their Frankenstein product people will buy it for a quick fix. If we listened to our bodies instead of people trying to sell us stuff we would be a much healthier nation.

  11. John Anderson 8 February 2013 at 1:45 pm #

    if a pice of butter and a piece of margarine are placed on a plate and ants are introduced they will devour the butter and leave the margarine well alone. They have not read any adverts etc and naturally know what is best for them. The biggest substance to avoid in heart disease is sugar and not fat.

  12. Fiona Benson 8 February 2013 at 2:00 pm #

    Basic common sense tells us that eating a product with just one or two ingredients (butter) will be healthier than any tub fat spread made up from industrially processed vegetable oils that were never part of our diet and a lengthy list of ingredients.

    Recently I entered into discussions with the British Heart Foundation (BHF). They expect members of the public to provide funding for different research projects, yet they are not much more than a marketing arm for Unilever (Flora), one of the largest global companies. A clickable link from the BHF web site:

  13. doug cook 8 February 2013 at 2:17 pm #

    I agree whole heartedly that excess omega-6 is bad, grain and seed oils are to blame but the margarines from 1966-1973 were also full of trans fats at that time, a major confounding variable no?

  14. John Cooney 8 February 2013 at 2:27 pm #

    Hey Stuart, I have IBS and have to listen to my body, It’s not a pretty sound. Seriously, though, listening to your body is well nigh impossible, the damage is often done before you know it. Is there ‘common sense’? I think that’s what we’re looking for.

  15. Sally 8 February 2013 at 5:41 pm #

    Joan Dye Gussow, long-time analyst and critic of the U.S. food system, summed it up:
    ‘I prefer butter to margarine, because I trust (grass fed) * cows more than I trust chemists.’

    *my words and brackets

  16. Hilda Glickman 8 February 2013 at 8:58 pm #

    It really is SO simple. The minute you do anything with oil squeezed from seeds you change it. Either it gets oxidised or you damage it in some other way. Its the processing that matters. Years ago when oils were used they were delivered to homes in dark bottles. We do need 0mega 6 but in the form of nuts or seeds. See video on net about how canola oil is made. How can any delicate food survive that?

  17. Gerda Flöckinger C B E 8 February 2013 at 10:19 pm #

    Dear Ms Glickman, you make a most important point. Is there any possibility at present for us to be informed about any details of the preparation procedures of foods ? However I have found that suppliers of really good quality foods are generally prepared to describe their methods openly. And I do still manage to get all my oils in dark bottles and my vegetables in paper bags.

  18. donald 9 February 2013 at 12:15 am #

    What would you advocate as a spread for those of us who are dairy intolerant John ? I currently use a non hydrogenated spread

  19. Nonmirecordo 9 February 2013 at 4:16 am #

    Has anybody checked for horse-meat in margarine?

  20. Healthy Longevity 9 February 2013 at 5:05 am #

    Peter Clifton has responded to Ramsden’s et al. previous meta-analysis as well this new paper:

    “The most important determinant of event reductions was the length of the intervention; and the studies using ALA-rich oil were much longer in duration than the LA-only studies. If only participants who had been on the diet for 1 year or more in the Minnesota experiment were to be assessed, then the ratio of total coronary events was fifty-four in the treatment group and fifty-eight in the control group.”

    “Trans-fatty acids may also play a role – the experimental polyunsaturated fat diet which incorporated soft margarines containing trans-fats would have increased trans-fat intake as was the case in both the Sydney study and the Minnesota study”

    “Although dismissed by the authors trans fats are likely to be responsible for the lack of benefit. The margarine would have contained at least 20% trans fatty acids and if the participants were eating 25g/day of margarine then they would be consuming 5g of trans which might represent about 2% of calories. From the Nurses Health study this could reduce heart disease by 40-50% which would almost completely remove the apparent increased risk from the N6 margarines. The more margarine eaten the greater the risk. The test margarine would have mostly supplanted butter rather than other margarines. The fall in total cholesterol seen not only reflects a fall in LDL cholesterol but also a trans induced fall in HDL cholesterol.”

    Here is another response to the reanalysis of the Sydney Diet Heart Study:

    ”Participants in the intervention group consumed “Miracle” Margarine, a product based on safflower oil. Hydrogenation of safflower oil itself creates a grainy product low in linoleic acid, so high-linoleic safflower oil margarine products were created by blending liquid safflower oil with another hydrogenated oil stock (3). Miracle Margarine used in the original study was either low in linoleic acid (due to hydrogenation of the safflower oil itself) or the oil was blended with another commercially hydrogenated fat to create a plastic margarine product. An investigation by Bernfeld, Homburger, & Kelley, published in 1962, indicated that the fatty acid composition of most margarines of the time were about 50-60% 18:1 monounsaturated fats (including oleic and trans isomers) and about 20-30% 18:2 linoleic acid, even in those products having high-PUFA claims on the label (4). None of the 22 margarines studied had a majority of fatty acids coming from PUFA. Another report from the same time period indicates that commercially produced hydrogenated fats, like those added to safflower oil to make margarine, were generally composed of about 25-40% trans fats (5). Fatty acid composition of margarines in the 1960s investigation were not comparable to liquid vegetable oil, despite package claims. The only reference supporting the healthful content of Miracle Margarine is a very general press release from the company who made the product (6). It is probable that Miracle Margarine had significant trans fatty acid content.”

  21. david manovitch 9 February 2013 at 1:53 pm #

    Mihikl believes onions and garlic may be harmful based on a You Tube presentation and other sources. Having performed a quick search I can only find numerous references to the health benefits of onions and garlic. It goes against the logic of the mediterranean diet does it not?
    Clearly eating purified vegetable oils is unnatural, as is butter as it has to be extracted from milk. Ideally fats should come as just a part of the ‘food package’, i.e attached to muscle, or in the body of the fish or the seed or nut, and not eaten separately. All this said, I no longer believe the saturated fat hypothesis of Cardio-vascular disease. The forces that have shaped the 20th C diet are from the dark side, or capitalism as it is otherwise known.

  22. Reijo Laatikainen 9 February 2013 at 4:31 pm #

    It’s interesting that Ramsden seems to have abandoned the inflammation hypothesis regarding omega-6 fatty acids. Not a word of it. I guess he have read the meta-analysis of RCTs by Johnson & Fritsche (2012) which showed: linoleic acid has zero effect on inflammation markers in humans. Now the theory is oxidatized linoleic acid particles. Time to move on, clearly.

    Of note, according to the meta-analysis of 63 RCTs by Mensink et al (2003) shortenings and other trans-fat-laden margarines provide better total cholesterol/HDL ratio than butter. Also, the controls were allowed to use the other margarines brands available at the time, as stated in the text. Thus, I don’t believe trans fat played a major role in this particular trial. They may have a role in Finnish Mental Hospital and Oslo Diet Heart studies.

  23. tony kerstein 9 February 2013 at 10:52 pm #

    There is one margarine that is healthy although ironically it was not created for that purpose. It was created for orthodox Jews who are not (for religious reasons) allowed to mix milk with meat. This is block Tomor(not the spreadible tub version which has more sunflower oil). It is made mostly from about half coconut oil and about half palm oil.

  24. Fiona Benson 9 February 2013 at 11:55 pm #

    Donald you asked:
    What would you advocate as a spread for those of us who are dairy intolerant John ? I currently use a non hydrogenated spread.

    Have you tried goat products? I have a friend who could not tolerate cow dairy products but found goat products gave her no problems.

  25. mhikl 11 February 2013 at 1:14 am #

    Looks like we’re all pretty converted to a style of health that bypasses commercial foods. What I find most appalling is that corporations in the food industry make baby foods that are detrimental to the future of our species. What I find even more appalling is that our governments let them get away with it. In a perfect world, little people would come first and those who provide for them would demand it.

  26. Aitch 11 February 2013 at 11:12 am #

    The point raised about the link between The British Heart Foundation and Unilever is interesting. The more I read this blog the more I see the links between the people giving us “nutritional advice” and big industry. Very enlightening. Thanks

  27. Nadia 11 February 2013 at 2:47 pm #

    I seem to remember reading somewhere that back in the day when they first started experimenting with organ transplants, patients were injected with Linoleic Acid to suppress their immune system and thus not reject the new organ. When these patients died from heart and cancer issues, they stopped using it……. Says it all really doesn’t it?

  28. Fiona Benson 12 February 2013 at 11:47 am #

    Nadia: Barry Groves writes about that connection with Linoleic Acid as an immunosuppressant in his article Polyunsaturated Oils Increase Cancer Risk ( The fully referenced discussion discusses that organ transplant experiences in the 4th section of that article under the heading “Polyunsaturated Fats suppress the immune system” .


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