I’ve written before about the dangers of omega-6 PUFAs in the diet, and how high intake of PUFAs in the Western diet may be a culprit in the significant increase in inflammatory diseases, including cardiovascular disease, type 2 diabetes, obesity, cancer, autoimmune disease, and more. (1, 2) We’ve known for a while now that a correlation exists between a rising intake of n-6 and increased mortality from heart disease. (3)
You may have already changed your diet back to one containing high saturated fat from butter, meat, and coconut products, much to the dismay of your doctor and perhaps even your skeptical family members. The belief that omega-6 rich vegetable oils are the “heart healthy” choice is pervasive, despite limited and controversial evidence. It can be difficult to convince others that you’re not asking for a heart attack by eating saturated fat.
Now, thanks to research published last week in BMJ, an old study is shedding new light on the omega-6 fatty acids and heart health controversy. The Sydney Diet Heart Study was a randomized controlled trial conducted from 1966 to 1973, comprising 458 men aged 30-59 years with a recent coronary event, such as a heart attack. Patients were randomized to either a control diet (e.g. no change) or an intervention diet, where they were instructed to increase their omega-6 PUFA intake to 15% of calories and to reduce saturated fat intake to less than 10% calories. Participants were provided with liquid safflower oil and a safflower oil based margarine to be used instead of animal fats. (They were also given safflower oil in capsules to take as a supplement. Yikes!)
As expected, those in the treatment group had a significant lowering of total and LDL cholesterol concentrations, which the original investigators assumed would therefore lead to the prevention of cardiovascular death. However, when accounting for previously lost data, this new analysis found that the intervention group instructed to eat more linoleic acid (n-6 PUFAs) actually had a higher risk of all cause mortality, as well as a higher risk of mortality from cardiovascular disease and coronary heart disease, than the group who received no dietary instructions.
Furthermore, an updated meta-analysis of linoleic acid intervention trials included in the paper showed no evidence of cardiovascular benefit. In other words, replacing saturated fat with high omega-6 vegetable oils is likely to put you at a greater risk for heart attack, and it certainly won’t provide any health benefits. It’s important to note that previous analyses that suggested increasing PUFA intake reduces the risk of CVD included both omega-6 and omega-3 PUFA together; the analysis in this study analyzed the effects of omega-6 linoleic acid separately.
Could “heart healthy” vegetable oils be putting you at risk for a heart attack?
So why are Americans still eating diets that are so high in omega-6 vegetable oils, with almost 9% of all calories from linoleic acid alone? (PDF) Despite the many studies that show the dangers of a high omega-6 PUFA intake, the conventional medical system is still preaching outdated and inaccurate information. The American Heart Association (AHA) recommends that we all aim for at least 5 percent to 10 percent of calories from omega-6 polyunsaturated fatty acids (PUFAs), and to limit saturated fat intake to less than 7 percent of total daily calories, similar to the recommendations made in the Sydney Heart Diet study. (4)
They suggest we choose “heart healthy” oils and margarines such as canola, corn, olive, peanut, safflower, sesame, soybean, and sunflower oils. This information is coming from the professional organization whose stated mission is “to build healthier lives, free of cardiovascular diseases and stroke.” But as we know by now, these guidelines are not going to protect anybody from a heart attack, and could likely put people at a greater risk for cardiovascular disease. (5)
As more evidence surfaces about the dangers of high omega-6 PUFA consumption, it will be more difficult to defend the current AHA guidelines for fat consumption that are currently promoted by conventional health professionals. It seems the tide may be turning (slowly) when it comes to dietary fat recommendations, but it will be interesting to see how the American Heart Association responds to this new study. While we wait for the policy makers and medical organizations to battle it out, I’ll stick to eating butter!
To read more about heart disease and cholesterol, check out the special report page.
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Hi, Chris,
Thanks for this article! I’m bookmarking it to use whenever people trot out articles like this one =X:
http://www.bbc.com/news/health-40300145
It makes me angry that in 2017, misinformation is still so widespread considering that you wrote this article FOUR years ago. Sighhh.
Is the message of the article that because a bad omega-3:6 ratio can potentially harm you, that saturated fat is good by default? What about studies that show decreased risk of heart disease and lower blood cholesterol when swapping saturated fat in the diet for vegetable oils?
In the study that Chris references (and links to the publication!), those participants who were told to increase omega 6s BUT also decrease saturated fats, lowered cholesterol but ended up with higher death rate and cardiovascular disease than those left to eat the average amount of saturated fat without increasing omega 6/ PUFA oils.
So his point is that sticking with (traditional) butter is (at worst!) neutral for heart health, if not good (we can’t tell from this study alone), in comparison with glugging the vegetable oils in an attempt to lower your cholesterol…
As I understand it, the body needs Omega essential fatty acids to manage life, as we know it.
The trick is BALANCE!
Omega 3 is an anti-inflammatory oil, whereas Omega 6 supports inflammation.
It is almost as if both need to be present to turn inflammation ON AND OFF as the particular situation demands.
In the distant past, there was no problem with this until our food supply was being manipulated by “scientists” to assuage “economists”, who in turn support “investors”.
All of these groups are responsible for a large part of our ills.
What about the evidence from Esselstyn, Ornish et al that with established heart disease, neither are likely a very good idea?
I understand that in the BMJ study, linoleic acid is less healthy/more dangerous than butter. But that doesn’t mean that butter is safe–just safer than linoleic acid. Where is the evidence that butter is perfectly healthy?
Mr. Kresser,
For the last three months I have been using Vince Gironda’s “Steak and eggs” diet to get back into shape. I use intermittent fasting and therefore only eat one huge meal a day from 6pm to 7pm. I eat one pound of red meat and fifteen eggs. The eggs are cooked with a full stick of butter (250 grams). It’s a very satiating meal to say the least. I lift weights daily and walk a lot. I have never felt better in my life but I am somewhat worried that my omega ratios are not as they should be since I haven’t been able to afford grass-fed stuff. I would really appreciate it if you could give me some insight on what I am doing and if it could destroy my health. Thank you.
I’ve been following a paleo type diet for a few months. I’ve eliminated all grains and seed oils. We regularly use ghee and coconut oil. I also have 2 eggs for breakfast every morning. I try to get pasture eggs when I can, but if not get the ones high in Omega 3s. I had a blood test recently, and my cholesterol was 216, which is considered borderline high. Of course the nurse gave me the ‘low fat diet and more exercise’ directive. Well, I probably could use more exercise, but my HDL was 69 and my Triglycerides were 67 which is very good. LDL was 143, which is also considered high, but there was no breakdown between the ‘good’ LDL and the ‘bad’ LDL. Since my HDL is great and my Triglycerides were low, I’m happy. Now to get my husband off the statins he’s been on for a few years…..
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Michael you should be able to unsubscribe at the bottom of any emails you receive from the site.
I think it is quite clear that excess omega 6 fats in the diet, especially when the source is pressed oil vs what is present naturally in certain whole foods, are no good. That said, I get concerned when we take information like this extrapolate out the conclusion that butter is “heart healthy”, implying that it somehow promotes cardiovascular health. I think at best this notion has not been proven, and at worst this idea is harmful and wrong and could be contributing to worsening cardiovascular health for many who choose to believe it (though not necessarily as bad what happens with excess intake of omega 6. For example, what do we make of a study like this? http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2584179/ Is butter really “heart healthy” Chris?
Daniel….that study says it was done on smokers. I wonder what that means if anything but it seems for sure that we are better off with MUFA and keeping sat fats and PUFA’s to a minimum, and unprocessed. Although some disagree, I try to subscribe to the Blood Type diet. Within the AB, the theme is low sat fats. Probably because of low stomach acid which reduces ability to process them.
Not to mention that it was an outpatient study taking into account one very isolated outcome not overall health.
The LA Veterans Administration Hospital Study was a very good closed ward random study that was carried out over 8 years and it showed that butter wasn’t unhealthy and even protective against the effects of smoking.
Chris talks about it in this podcast:
http://chriskresser.com/the-healthy-skeptic-podcast-episode-11/
Thanks Robin. I did take into account that they are trying to sell something. However, the group that hosts this web site are all MD’s or PHD’s which made me think that they developed this product because they believe in it. Whether they are right of wrong is another story. I really do appreciate you taking a look at it. : )
Carol,
I’d be a bit suspicious of a site whose main purpose appears to be selling a product. I had a quick read through the advancedbionutritionals page you linked to and could see no references for the studies he mentions either. They may exist, but without being able to check out further my instinct is that you can trust information on Chris’s site more than the information on that site.
Having said that I tend to agree with Brian Skory that PUFAs in themselves (including omega 6) may not be so much to blame. The Sydney study used sources of omega 6 fats that as far as I understand could have contained up to 15% trans fats. That looks to me like the most likely reason for the poor health outcomes of the omega 6 group.
Number one – Heart attacks are not caused by diet, they are a by-product of a healing phase, the healing crisis of a territorial biological conflict in healing.
Number two – all the vegetable oils on supermarket shelves have been adulterated (hydrogenated) and are therefore foreign to nature and our bodies. As such they contribute to chronic inflammation of the cardiovascular system, which , of course is not beneficial to us at all!
The best way to live is to consume all nutrients in their natural state – RAW !
The next best way to sustain oneself is to minimize the application of heat in order to preserve as many enzymes, vitamins and trace minerals as possible and stay away from “quacks” also known as doctors and pharmaceuticals.
Chris, great stuff as usual. it might help to know that the 2013 AHA guidelines state that sat fats are not the problem. They even state that replacing sat fats with carbs increases risk of chd. They do still state that replacing sat fats with poly unsat fats is beneficial.
http://circ.ahajournals.org/content/127/1/e6
Dan,
The reason for the recommendation to replace saturated fat with polyunsaturated fat was based off of studies that when pooled has some statistical significant improvement in outcomes. But what this artcle mentions is that these pooled studies did not differentiate between the type of polyunsaturated fat and in many cases contained BOTH n-3 and n-6. So was the beneficial effect demonstrated secondary to the fact that omega 3 polyunsaturated was present? This article points out that the studies in which n-6 polyunsaturaed fat were compared to Saturated fat, n-6 clearly had worse outcomes and now when this lost data is pooled with the previous pooled study, there was no significant difference between the two groups (all types of polyunsaturated fat and saturated)
Thanks David
If you wouldn’t say that your house is based off of its foundation, why would you day something is based off of something else. Save the English language!
http://www.advancedbionutritionals.com/Special-Offers/201212/Advanced-EFA-Formula-ABRRA4C2.htm
Now I am really confused!
OK, unless I’m reading this incorrectly, there’s a HUGE hole in this study. Two variables were changed. Saturated fat was decreased below 10% and n-6 was increased to 15%. Which caused the problem?? Decreasing the SF? Increasing PUFA? A combination of both? I love my butter and other saturated fats, and my health will certainly suffer by decreasing them to those levels. N=1 has clearly demonstrated that to me. But based on all of the new research I’m seeing on n-6, I’m not convinced that PUFAs are the demons we’ve been led to believe they are.
Just to be clear, I’m not disputing what the study demonstrates – that replacing SF with margarine and safflower oil will be detrimental to health. Just noting that with regard to “higher risk of all cause mortality, as well as a higher risk of mortality from cardiovascular disease and coronary heart disease,” it’s a little hard to tell which was the cause – decreased SF or increased PUFA.
I think you’ve hit on the inherent problem in attempting to design flawless nutrition studies: when one nutrient is decreased, another must be increased to maintain caloric balance. Also, unless you’re using isolated nutrients (which creates its own problems), decreasing one nutrient present in a whole food will also decrease the other nutrients present in that whole food. It’s truly impossible to eliminate all of the confounding variables. To me, the only way to produce effective nutrition science would be to take a step back from the individual nutrients and do studies that control the entire diet- say, one group eats a diet in line with the Dietary Guidelines, and the other eats a Paleo diet. Also, they’d need to look at mortality, because intermediate biomarkers have major limitations. The results wouldn’t tell you anything about individual nutrients, but they’d sure tell you something about a healthy lifestyle! And since people eat FOOD, not nutrients, I think the results would be far more applicable. Even studies comparing two foods- say, one group eats butter, while the other eats canola oil – would be highly useful. Again, wouldn’t tell us anything about specific nutrients, but it would tell us which food is likely better for you!
I take my Kerrygold butter medicine at least once daily! Sometimes more often than that! 😉