Omega-3 Fatty Acids May Not Reduce Heart Disease Risk

Contrary to previous findings, a new study suggests that omega-3 fatty acid supplementation may not reduce the risk for heart disease.

Dietary sources of omega-3 fatty acids include fish oil and certain plant and nut oils. Fish oil contains both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), while some nuts (such as English walnuts) and vegetable oils (such as canola, soybean, flaxseed, linseed and olive oils) contain alpha-linolenic acid (ALA).

Several well-conducted randomized controlled trials have reported that in people with a history of heart attack, regular consumption of oily fish or fish oil or omega-3 supplements reduces the risk of nonfatal heart attack, fatal heart attack, sudden death and all-cause mortality (death due to any cause). Most patients in these studies were also using conventional heart drugs, suggesting that the benefits of fish oils may add to the effects of other therapies.

Several large studies of populations have also examined the effects of omega-3 fatty acid intake on stroke risk. Some studies suggest benefits, while others do not. Effects are likely on stroke risk, and very large intakes of omega-3 fatty acids may actually increase the risk of hemorrhagic (bleeding) stroke. At this time, it is unclear if there are benefits in people with or without a history of stroke, or if effects of fish oil are comparable to other treatment strategies.

In a new study, researchers conducted a comprehensive literature search for well-designed clinical trials evaluating the effects of omega-3 fatty acids on death due to heart disease, sudden death, heart attack, stroke and death from any cause. Twenty studies assessing 60,680 individuals were ultimately identified for inclusion.

From the 20 studies, 7,044 deaths from any cause, 3,993 deaths due to heart disease, 1,150 sudden deaths, 1,837 heart attacks and 1,490 strokes were identified.

Through data analyses, the researchers found that a significant association between omega-3 fatty acid intake and risk for death from any cause, death due to heart disease, sudden death, heart attack or stroke, was lacking.

The authors concluded that omega-3 fatty acid supplementation may not reduce the risk for heart disease or stoke. However, additional research is necessary to further evaluate these findings.

For more information about integrative therapies for heart disease prevention, please visit Natural Standard's Comparative Effectiveness Database.

For more information about fish oil, please visit Natural Standard's Foods, Herbs & Supplements Database.

Comments

[nb]

I agree with SS in that meta-analyses may be biased. This study is a revelation to me, because doctors have been telling my grandparents to take omega-3 supplements to promote heart disease prevention for years, and they take them religiously. Many elderly persons take omega-3 in very large quantities, thinking they are doing themselves a favor by taking omega-3 supplements and strengthening their heart, which may not be the case after all, and even put them at increased risk of bleeding. Considering a lot of people are on aspirin and/or Coumadin nowadays, doctors and pharmacists should make sure the patient is taking omega-3 supplements in adequate amounts, if he chooses to take them.

[nh]

This is an interesting article regarding fish oil use in regards to heart disease. In all my teaching as a student, I have seen evidence that fish oils do reduce heart disease risk. I have not looked at the studies that are cited here, but I am interested in looking at what types of fish oils were used in these studies. There are many kinds of fish oil, so a few differences could definitely skew results. Also, I find results like discouraging. Not because they might be factual but because they could discourage some patients from taking a drug that might potentially help them. Hopefully, studies fish oil research will continue because it is an important topic.

[zw]

Despite this negative press for fish oil supplements, I wonder about the implications of this data on overall cardiac health. It's back to the age-old debate; is lowering cholesterol or blood pressure significant if a product is not proven to produce significant decreases in mortality? Though this data does not show significant decreases in overall mortality, it also does not show there is no benefit whatsoever. Perhaps it still has positive effects on quality of life. More research is clearly warranted.

[tw]

ML brings up an interesting point on how this study was conducted. It is interesting to see that two studies were weighted much more strongly than most of the other studies in this meta analysis. The study design is not something readers immediately evaluate when looking at an article such as this, even though it is incredibly important when it comes to evaluating the results. Thanks to ML for bringing this up for others to see!

[My Lien]

The article will make it more challenging in counseling consumers interested in fish oil and omega-3 supplementation. Perhaps it is another reminder that there are no magic bullets, and reinforces the importance of a healthy-lifestyle.

[ML]

While this study's conclusion may appear disheartening, if you examine the review further, the conclusion may not be so definitive. The 20 studies that were reviewed varied significantly between each other, and the weight of each study varied depending on the number of subjects enrolled. Two studies in particular carried a majority of weight (Tavazzi 2008, 28.99% and ORIGIN 2012, 26.23%). Most of the other studies were weighted as <1%. The higher weighted studies should be examined more closely before this generalization is made regarding fish oil. Doses of fish oil varied between studies, and this should be considered, as well.

[ss]

I personally think that meta-analysis and systemic overview are overrated. people forget about the publication bias associated in these pooled analyses.
my father-n-law has been taking fish oil capsules for years and his blood pressure and cholesterol is under control.I would not tell him to stop taking the fish capsules unless someone come up with some severe side effect from it.

[Robynholman]

I agree with Angela's comment that omega-3 fatty acids have additional health benefits. The meta-analysis only shows that there may not be a benefit previously thought to exist, but it certainly does not show harm can occur after ingestion of fish oil or other sources of omega-3 fatty acids. This meta-analysis will likely cause additional clinical trial data to be released regarding the role omega-3 fatty acids can play in heart disease, which is great from a scientific evidence viewpoint.

[ee]

Wow. This is article is very interesting, but it degrades the benefits Omega-3 fatty acids have been reported to have for years now. I wonder what this finding will do to the market and proponents of the use of omega-3 fatty acids for heart health.

[weezy]

This may be an unfortunate finding. I know I have encountered very many patients that take fish oil and omega-3 supplements due to their supposed cardiovascular effects. It will be interesting to see more information revealed on this topic once more research is done to determine a more definite answer. This will be useful to know as pharmacists to counsel our patients since this drug is widely used by consumers.

[bc]

It is very interesting to see these results from such a large study. Omega-3 fatty acids are widely used to prevent heart disease among other uses. It would be beneficial to look at the characteristics of patients included in the studies, as it seems like a high number of deaths in comparison to the number of patients studied. Perhaps these patients were already at a much higher risk of death from any cause. I wonder how omega-3 fatty acids would compare to aspirin for heart disease prevention.

[Angela]

This article speaks to how new research can contradict commonly accepted ideas about health and medicine. Individuals should also keep in mind that fish oil and omega-3 fatty acids have other possible benefits besides heart health, including lowering blood pressure and cholesterol, and reducing symptoms of rheumatoid arthritis.