A new meta-analysis published by the U.S. Agency for Healthcare Research and Quality finds evidence that omega-3 consumption lowers triglycerides and raises HDL cholesterol, but its findings on other cardiovascular health markers are less strong.
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Cardiovascular health disease (CHD) has long been one of the strongest research areas for health benefits related to omega-3 consumption, but a new federal report offers a more measured take on exactly which CHD markers may be influenced by omega-3s. The Global Organization for EPA and DHA Omega-3s (GOED; Salt Lake City, UT) notes that the report found “mixed results” of CHD benefits from omega-3 consumption, some of which are at odds with GOED’s own research.
The new report, published by the U.S. Agency for Healthcare Research and Quality (AHRQ), includes 61 randomized controlled trials and 37 prospective longitudinal studies published since 2000, which GOED suggests is a “relatively small number of studies” given the many CHD health outcomes assessed. The report authors also describe their inclusion and exclusion criteria as “arbitrary” in terms of sample size, follow-up duration, and other factors, GOED points out.
Based on their meta-analysis, the report’s authors find moderate-to-high strength of evidence (SOE) that increased consumption of marine oil omega-3s (EPA, DHA, and DPA) lowers triglycerides, raises HDL cholesterol, lowers the ratio of total cholesterol, and does not affect major adverse cardiovascular events. However, the report also finds a small but statistically significant increase to LDL cholesterol as a result of higher omega-3 intake.
Weaker SOE associations were found for the effects of omega-3 consumption on decreased risk of CHD death, coronary heart disease, myocardial infarction, congestive heart failure, and ischemic stroke. The report also concludes there is “low SOE or no association with CHD death or hemorrhagic stroke.”
While GOED says most of the report’s findings were not unexpected, it does note that GOED’s own commissioned meta-analysis on CHD risk paints a different story of the omega-3 heart-health benefits in high-risk populations. For instance, that analysis, which is currently being revised for resubmission, found that consuming EPA and DHA omega-3s significantly reduced CHD risk among participants with elevated triglycerides and elevated LDL cholesterol.
The AHRQ report also finds no overall omega-3 marine oil benefits to systolic or diastolic blood pressure, which could have implications for GOED’s qualified health claim petition linking EPA and DHA consumption with reduced blood pressure.
“At the moment, it’s not clear if this will adversely affect GOED’s qualified health claim petition given that subgroup analyses in healthy populations demonstrated a significant reduction in diastolic blood pressure and a borderline-significant reduction in systolic blood pressure,” GOED says, in its announcement addressing the report. “The current review included fewer than half the number of studies as were in the GOED commissioned blood pressure meta-analysis.”
Nutritional Outlook Magazine
Balk EM et al., “Omega-3 fatty acids and cardiovascular disease: an updated systematic review,” Evidence Report/Technology Assessment No. 223, AHRQ Publication No. 16-E002-EF (July 2016)