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‘Insufficient’ evidence for omega-3 heart benefits, suggests meta-analysis

1 commentBy Nathan Gray , 10-Apr-2012
Last updated on 10-Apr-2012 at 14:41 GMT

There is insufficient evidence for a secondary preventive effect of omega-3 fatty acid supplements against overall cardiovascular events among patients with a history of cardiovascular disease, according to new research. However industry has said the analysis of previous study is ‘limited’ and ‘inaccurate’.

The meta-analysis – published in JAMA’s Archives of Internal Medicine – reports that the evidence from previous clinical trials assessing the benefits of omega-3 fatty acid supplementation on heart protection is “insufficient.”

"Our meta-analysis showed insufficient evidence of a secondary preventive effect of omega-3 fatty acid supplements against overall cardiovascular events," explained the authors, who were led by Dr Sang Mi Kwak of the Center for Cancer Prevention and Detection, Republic of Korea.

"Likewise, we found no beneficial effect of omega-3 fatty acid supplements on other cardiovascular events, such as sudden cardiac death, myocardial infarction (fatal or nonfatal heart attack), angina and unstable angina, congestive heart failure, and transient ischemic attack and stroke, or on all-cause mortality," they wrote

However, many industry bodies have reacted to the findings, arguing that the results do not consider the totality of the evidence for omega-3’s heart health benefits.

Dr. Cara Welch, vice president of scientific and regulatory affairs for the Natural Products Association (NPA) noted that there is a “wealth of evidence showing the benefits of omega-3 fatty acids on cardiovascular disease.”

Whilst Taylor Wallace, Ph.D., senior director, scientific and regulatory affairs for the Council for Responsible Nutrition (CRN) said the findings conflict with the totality of scientific evidence “which finds benefit for omega-3 EPA and DHA for heart health.”

“This conclusion is not one that the scientific community has rushed to make. Rather, it is based on epidemiological and observational studies as well as clinical trials looking at a variety of cardiovascular disease outcomes," added Welch. 

Study details

Kwak and his colleagues conducted an analysis to examine the association between use of the omega-3 fatty acid supplements eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and risk of cardiovascular disease in people with existing heart problems.

The researchers analysis included data from 14 randomized, double-blind, placebo-controlled trials that involved 20,485 patients with a history of cardiovascular disease (CVD). They found that supplementation did not reduce the risk of overall cardiovascular events, all-cause mortality, sudden cardiac death, myocardial infarction, congestive heart failure, or transient ischemic attack and stroke.

“There was a small reduction in cardiovascular death, which disappeared when we excluded a study with major methodological problems,” said Kwak and his team.

“Our results showed insufficient evidence of a secondary preventive effect of omega-3 fatty acid supplements against overall cardiovascular events among patients with a history of cardiovascular disease,” they added.

Underpowered

Harry Rice, PhD, VP of regulatory and scientific affairs for the Global Organization for EPA and DHA Omega-3 (GOED) told NutraIngredients that many of the studies included in the meta-analysis were underpowered because they contained too few participants – “resulting in a failure to detect an effect, not a failure to demonstrate an effect!"

"The totality of the publicly available scientific evidence demonstrates a cardiovascular benefit of EPA and DHA in healthy populations, as well as in the majority of populations with pre-existing cardiovascular ailments,” said the omega-3 expert.

“Given the manner in which this meta-analysis was conducted, the scientific community, physicians and consumers alike should give minimal credence to the results," he said. 

Dr Welch of the NPA echoed such sentiment, adding that she ‘strongly’ believes the meta-analysis is “an inaccurate depiction of the benefits of omega-3 on cardiovascular health.”

“Research on omega-3s will continue, as well as meta-analyses of published research, but for now, a diet high in omega-3s should continue to be recommended,” she said.

 

Source: Archives of Internal Medicine
Published online ahead of print, doi: doi:10.1001/archinternmed.2012.262
“Efficacy of Omega-3 Fatty Acid Supplements (Eicosapentaenoic Acid and Docosahexaenoic Acid) in the Secondary Prevention of Cardiovascular Disease”
Authors: S.M. Kwak, S.K. Myung, Y.J. Lee, H.G. Seo

1 comment (Comments are now closed)

Fish-oil band-aid

Meta-analyses like this say nothing about the actual studies' results and everything about the studies' methodology.

Besides, taking fish oil with pre-existing cardiovascular disease is, really, like applying a band-aid on a broken head. It may have some benefits, but unlikely will affect such parameters as "sudden cardiac death..." and "all-cause mortality."

Alas, another case of lost taxpayers' money.

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Posted by Pavel Axentiev
10 April 2012 | 19h42

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