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Studies question fatty acids' heart benefits
March 17th, 2014
05:00 PM ET

Studies question fatty acids' heart benefits

Many health organizations, including the American Heart Association, recommend eating polyunsaturated fatty acids - particularly those called omega-3s and omega-6s - for heart health.  But new research once again casts doubt on whether these fatty acids have any effect on reducing your risk of heart disease.

A meta-analysis published Monday in the journal Annals of Internal Medicine did not find significant evidence to support eating a diet high in polyunsaturated fatty acids and low in saturated fats. It didn't seem to matter whether the fats came from dietary sources or supplements.

"Current evidence does not clearly support guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats," the study authors concluded.

And a second study, published in the journal JAMA Internal Medicine, found that supplementing a diet with long-chain omega-3 polyunsaturated fatty acids did not reduce study participants' heart disease risk.

Background

Fatty fish such as salmon, trout and herring all have high levels of polyunsaturated fats; so do nuts, seeds and several vegetable oils, according to the American Heart Association. Monounsaturated fats can be found in olive oil, canola oil, avocados and peanut butter, for example.  The AHA recommends that most fats you eat be polyunsaturated or monounsaturated.

A meta-analysis looks at past studies to see if patterns in the data hold up across many experiments.  In that sense, the research method is stronger than just one study.  But there could be inaccuracies and biases in the individual studies analyzed, as well as methodological differences among them that make conclusions about the combined findings more complicated.

The first study

For this new meta-analysis published in Annals of Internal Medicine, researchers reviewed a large spectrum of studies on the subject: 32 observational studies looking at fatty acids from dietary intake, 17 observational studies of fatty acid biomarkers, and 27 randomized, controlled trials examining fatty acid supplementation.

Focusing on the randomized trials of supplementation, the meta-analysis found that long-chain omega-3 and omega-6 polyunsaturated fatty acids did not reduce the likelihood of coronary events.  But further study of this subject is warranted, researchers wrote, as "the available evidence is generally limited."

The meta-analysis found no consistent association between a person's total saturated fatty acid intake and his or her coronary risk. Researchers also did not find an association between monounsaturated fatty acid consumption and coronary risk.

The second study

A second study published Monday also failed to find fatty acids lead to a risk reduction in cardiovascular events.

Research in the journal JAMA Internal Medicine found that supplementing a diet with long-chain omega-3 polyunsaturated fatty acids did not reduce a person's risk of cardiovascular disease. Researchers analyzed data from 4,203 elderly people with age-related macular degeneration.

So what's going on? There are a few shortcomings in this study, Dr. Evangelos Rizos and Dr. Evangelia Ntzani wrote in an accompanying commentary. For instance, 20% of the study participants had known cardiovascular disease, and participants were aware of which treatment they were receiving. The authors also did not publish information about participants' triglyceride levels, which are thought to be reduced by omega-3 supplementation.

Given the lack of evidence in previous studies for omega-3 supplementation, Rizos and Ntzani said that more similar randomized trials would be "unjustified." They instead call for a meta-analysis and for trials that "focus on the remaining gaps of knowledge" such as studying the effect of high doses of omega-3s on patients with high levels of triglycerides.

Takeaway

"Patients raising the question of taking omega-3 supplements should be informed of the uncertainty surrounding their choice, and regular dietary consumption of (whole) fish should be preferentially encouraged as a source (of these fatty acids)" instead of supplements, Rizos and Ntzani wrote.

International guidelines do not agree on  how much, and which types, of fatty acids are best to eat. There is no reason to change the current guidelines put forth by the American Heart Association, said Linda Van Horn, spokeswoman for the AHA.  She said this study's results are not surprising.

The general advice - avoid trans fats, reduce saturated fat, increase intake of fruits, vegetables and whole grains - still stands, Van Horn said.

Duffy MacKay, senior vice president for scientific and regulatory affairs at the Council for Responsible Nutrition, said in a statement that the researchers of the Annals of Internal Medicine study raise an "interesting viewpoint" but a "potentially irresponsible one."

"Unfortunately, their conclusions, if taken to heart, leave consumers to rely on genetics and fate to avoid coronary heart disease - an unacceptable situation given the fact that the scientific literature contains so many studies that point to benefit for omega-3 fatty acids," MacKay said.

The AHA is holding a national meeting this week; experts there will have the opportunity to "consider what this paper means," Van Horn said.


soundoff (49 Responses)
  1. Tim

    Given the lack of overall impact from any fatty acids, it sounds to me like neither study was properly powered to detect cardiovascular benefits. In essence, they appear to both be poorly designed studies.

    March 17, 2014 at 17:29 | Report abuse | Reply
    • Paul

      So essentially you are saying that since it did not provide the result you wanted (overall impact of omega 3) the study was by definition flawed? Kind of backwards thinking.

      March 18, 2014 at 07:54 | Report abuse |
    • Whatnow

      We continue to search for a magic ingredient, food source or activity that is the secret to health and longevity. One day we will discover that the real secret is real food which includes real proteins, not modified, drug induced or a chemistry experiment substance designed to replace meat meats. My ancestors lived to their early 100's eating pork, beef, home grown vegetables, seasonal fruits and occasionally, deserts. The difference was, their food was real and they worked harder to put it on the table. Yes, this may be anecdotal evidence, but I will just bet there are many out there with the exact same "anecdotal" evidence.

      March 18, 2014 at 09:31 | Report abuse |
    • Tim

      The Annals study also found that trans fats and saturated fats had no effect. In fact, it essentially found that none of the fatty acids studied had a significant effect. When none of the things measured have an impact, one must start questioning the design of the study.

      March 18, 2014 at 11:49 | Report abuse |
    • Organic1

      Makes great marketing tools tho.

      March 18, 2014 at 14:13 | Report abuse |
    • Gayle63

      Whatnow: I would add exercise to that list of natural healthy foods.

      March 18, 2014 at 14:31 | Report abuse |
    • George

      The studies are ok, it's the reporting spin on those studies that's wrong. Basically nothing new here. Fast food burgers are still bad for you and there are indeed benefits to omegas and such.

      March 18, 2014 at 16:35 | Report abuse |
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      March 20, 2014 at 21:54 | Report abuse |
  2. Adam Ismail

    Actually both of these studies found statistically significant reductions in CVD events from EPA and DHA omega-3s, but those findings were buried in the papers and not the highlight of the press releases issued to promote the studies.

    March 17, 2014 at 17:50 | Report abuse | Reply
    • L Pam

      No they did not. They specifically found that they were statistically insignificant – the opposite of your invented claim.

      March 18, 2014 at 09:13 | Report abuse |
    • Tim

      Yes they did. Clearly you did not read the full text of the study.

      March 18, 2014 at 11:51 | Report abuse |
  3. cali girl

    Eat Salmon with Peanut Butter?

    March 17, 2014 at 18:49 | Report abuse | Reply
  4. srichey321

    Eating this stuff in place of alcohol, processed food and other crap will reduce the risk of heart disease.

    March 17, 2014 at 20:45 | Report abuse | Reply
  5. Sue

    If medical science would start looking at the overall process, they would realize that our bodies need to be in balance. Having a healthy heart requires more than just looking at omega 3 or omega 6 oils. It's the balance between vitamins, minerals, essential fatty acids, and amino acids that will determine how healthy someone's heart is. Let's stop looking for the magic bullet, and start looking at what people are eating, and what they need to add to their diets. It is really that simple.

    March 18, 2014 at 00:12 | Report abuse | Reply
    • awwest51

      excellent, couldnt have said it better....no magic bullet, one needs it all, including saturated fats....BACON!

      April 2, 2014 at 12:26 | Report abuse |
  6. Lisa Te Morenga

    My collegues and I provide an opinion on the review published in the Annals of Internal Medicine (see link below). We have concerns about some aspects of this review, in particular the lack of context around the totality of the evidence. Hence we suggest that the best evidence for national guidelines is still that which encourages the replacement of saturated fats with polyunsaturated fats – with the latter ideally being long-chain omega-3 fatty acids (as found in fish, flax seed and nuts).

    https://blogs.otago.ac.nz/pubhealthexpert/2014/03/18/a-new-review-on-dietary-fats-putting-its-findings-in-context/#more-769

    March 18, 2014 at 05:30 | Report abuse | Reply
    • orionantares

      Polyunsaturated fat intake needs to be in balance, too much O6 without enough O3 is a bad balance and a very easy trap to fall into with prevalent food selections. On top of that, polyunsaturated fats are the most volatile fats, the most prone to going rancid and contributing to these heart issues. As far as long-chain omega-3s, those aren't found in flaxseeds or nuts, only in animal sources, sea vegetables, and produced from certain fungi used in fermentation.

      June 17, 2014 at 17:53 | Report abuse |
  7. Wenchypoo

    The real underlier not mentioned here is sugar–Omega-3 raises blood sugar, and it's the constant blood sugar elevation of diet and fish oil supplements that have more effect on the heart (as in heart disease) than the saturated fat briefly mentioned. If exercising, saturated fat is burned off as fuel FIRST before any other fat–meaning it doesn't stay in the blood long enough to be the source of heart disease. Sugar, on the other hand, hangs around, may feed the brain and cells, but we take in WAY TOO MUCH of the stuff, so the majority gets stored as fat. When the fat stores get backed up, the sugar lines our arteries and is commonly mistaken for cholesterol, heart disease, and atherosclerosis.

    In other words, IT'S THE SUGAR, STUPID!! Not the FAT at all.

    March 18, 2014 at 06:30 | Report abuse | Reply
    • awwest51

      nail on the head with the sugar conclusion.

      April 2, 2014 at 12:32 | Report abuse |
  8. steve

    The more I read the more im starting to think its 99% genetics and luck with most things. Dont smoke, dont get fat- exercise. Do those three things and you might still die of a heart attack but probably reduce the risk a lot. Eat fruit and vegetables- that one will be next to fall.

    March 18, 2014 at 08:38 | Report abuse | Reply
    • Ann

      "fruits and vegetables the next to fall"...I thought thay already had...Paleo says no beans, beware of nightshades (peppers, tomatoes, eggplant), soak your nuts (stop it now), cook your spinach,........

      March 18, 2014 at 13:00 | Report abuse |
  9. Ryan D

    So basically, we're back to square one.

    I think this highlights the need to stop basing every medical guideline on flawed statistical methods, and instead on actual hard science. I realize that's not always possible and very complicated, but these statistics studies are completely unreliable given how many variables can affect the results.

    March 18, 2014 at 09:20 | Report abuse | Reply
  10. Forteaneye

    Fish oil leads to massive depletion of feeder stock for larger fish. Also heavy in mercury and other poisons. A better solution is flax seed oil. Same Omega 3 benefits.

    March 18, 2014 at 10:12 | Report abuse | Reply
    • bob dolio

      This is not true. Only EPA/DHA omega 3 are beneficial, which is found in marine oil and in chicken and beef in smaller amounts. Flax seed oil and other plant based fats only contains ALA, this is only converted to EPA/DHA very inefficiently, less than 10%, while ALA has no proven benefits.

      March 18, 2014 at 12:16 | Report abuse |
    • ellid

      I tried both, and got horrendous migraines.

      March 18, 2014 at 12:21 | Report abuse |
    • Karen

      Just to let Bob know,there are vegan DHA/EPA supplements available.It's derived from Algae

      March 18, 2014 at 13:27 | Report abuse |
    • Bilson

      You all seemed to have missed the point that in the dozens of studies there is NO beneficial effect from these supplements. Save some money and forget it. Note that the article also mentions that there are NO deleterious effects from saturated fats. Just like there is no evidence that salt increases coronary disease and there is no evidence that dietary cholesterol intake influences blood cholesterol levels. Like the person above said – it'a all genetics.

      March 18, 2014 at 22:59 | Report abuse |
  11. Lisa

    I'll stick to my omega 3 thank you!

    March 18, 2014 at 13:14 | Report abuse | Reply
  12. Ed - Spring, TX

    If you eat a crappy diet and then take a few fish oil capsules every day and expect miracles then you're dreaming. That is probably what most people in these studies did. Very few people actually eat an optimum or even close to optimum diet.

    March 18, 2014 at 13:41 | Report abuse | Reply
  13. kafantaris2

    Wanna help your heart?
    Walk.
    And stand.
    And get some sleep.

    March 18, 2014 at 13:45 | Report abuse | Reply
  14. Jakob Stagg

    It is beginning to look like all medical/health information is conflicting. There seems to be no agreement about what is good for us and not. Recently, I went to a new doctor. Nearly everything prescribed previously or recommended, was advised to change or stop. Everything I have eaten or ingested in my life has been declared good or bad for me. Often at the same time.

    No wonder why the American medical industry is among the least effective on the planet, and costs the most. What is wrong? It obviously can't be both. It sure doesn't build confidence or trust.

    March 18, 2014 at 14:58 | Report abuse | Reply
    • Guest

      Its a myth that the American health care system is terrible in comparison to others

      March 18, 2014 at 17:29 | Report abuse |
    • Lou Garoo

      Guest: Given that groups ranging from the CIA to the World Health Organisation have studied the US health care "system" and found us to be on par with major industrialized countries such as Cyprus and Honduras, can you cite a major, peer-reviewed source for your assertion to the contrary?

      True, IF you have sufficient money and the right connections, it's possible to obtain top-class health care in this country but the vast majority of us will never be in that august group. We average people continue to pay more per capita than citizens of every other industrialized nation on earth while being sicker and dying sooner, all in the name of American "exceptionalism".

      March 18, 2014 at 22:02 | Report abuse |
    • Whatnow

      Guest, as a society, we truly need to quit spouting unsubstantiated ideas as if they are fact. It may be that you hold the opinion that we have the best health care, but that is not a fact. If we all believe the misinformation, we stop striving to improve. So, it is better to accept that we are number 37 or 38 on the international scale in healthcare and work to improve.

      March 19, 2014 at 09:53 | Report abuse |
  15. Anastasia Beaverhausen

    Nothing is healthy. What with pollution, fast food, chemicals in everything, frankenfood and Monsanto, it's a miracle we're not all dead by 30.

    March 18, 2014 at 15:44 | Report abuse | Reply
  16. SixDegrees

    "the scientific literature contains so many studies that point to benefit for omega-3 fatty acids"

    Well, sure. But, as the meta-analysis of those articles – and many other articles that don't point to such a benefit – shows, on the whole there's apparently no real benefit to be had.

    I'm often skeptical of such meta-studies, but it isn't at all hard to see that if you look only at the studies that show a benefit, you're skewing the results something fierce.

    March 18, 2014 at 16:20 | Report abuse | Reply
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    March 18, 2014 at 17:27 | Report abuse | Reply
  18. Enough is Enough

    @The GOP Solution – Had to make a political statement under a health related article, didn't you.....you really need to get a life......

    March 18, 2014 at 18:19 | Report abuse | Reply
  19. Garden child

    I lowered my cholesterol almost 20 points by taking omega- 3 so I'll keep to it, seems to be working great for me!

    March 18, 2014 at 20:03 | Report abuse | Reply
    • orionantares

      Yea, I lowered my cholesterol by 57 points and dropped 40 pounds by cutting out both excess and rancid sources of omega-6s, then increasing omega-3 and saturated fat intake. Your body really doesn't need a lot of polyunsaturated fats but it does need a close to 1:1 ratio of O6:O3 fats plus you need to treat those fats correctly so they don't become rancid and cause damage. Most vegetable oils, lots of nuts and seeds and soy, and grain-fed animal products are huge sources of omega-6s. On top of that those sources are often cared for or used poorly which causes those fats to go rancid, soy bean or corn oil are the most common cooking and frying oils because they are so cheap but they have some of the highest O6 content.

      June 18, 2014 at 10:46 | Report abuse |
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  21. Kate Johnson

    Seems this study was very narrow in it's focus with some questionable studies included, which is always a danger with meta analysis of this kind. In my own experience, both my sister and I had high cholesterol and after taking fish oil for a month it went to normal and we continue to take it and our cholesterol continues to be normal, so I think I'll stay on it thanks!!

    March 19, 2014 at 13:05 | Report abuse | Reply
  22. jonathanlk

    Not sure fish oil helps me. I had high cholesterol and it didn;t help at all, but neither did any of my other dietary improvements and excercise. I am on Lipitor and that works (it is now about 175 total and my ratio of bad to good is now less than two). But why do we get so much advice before there is ample evdence to support it? Maybe we should be more demanding of proof before we follow and believe broad assertions that might impact how we behave whether it is science, health, or even religion LOL. Would it be safer to rely on knowledge rather then a prescribed belief? I would rather be in the know.

    March 19, 2014 at 15:24 | Report abuse | Reply
  23. Katie

    I think exercise is key to a healthy heart. And I personally take omega 3 supplements – I believe they are good for you, despite whatever scientific proof may surface from one week to the next. But I believe that the worst thing for you is refined carbs. White bread, white sugar, etc are the worst things for your heart – in my opinion! But there us some poof here to back me up before anyone asks me why I think so: http://www.bulkpowders.co.uk/blog/research-sheds-light-links-saturated-fat-health/

    March 21, 2014 at 06:34 | Report abuse | Reply
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    March 28, 2014 at 08:32 | Report abuse | Reply
  26. awwest51

    you all make it far too complicated....i eat whatever i want and any amount, too.. my numbers are well within healthy recommended guidelines....you all obsess too much

    April 2, 2014 at 12:20 | Report abuse | Reply
  27. Verimius

    The Council for Responsible Nutrition, quoted at the end of the article, is a trade organization of the dietary supplement industry. They are hardly likely to support anything that reduces sales of their products, like omega-3 pills.

    April 16, 2014 at 13:09 | Report abuse | Reply
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